NISTIR 5625 A Survey of Steel Moment-Resisting Frame Buildings Affected by the 1994 Northridge Earthquake Nabih F,G Youssef David Bonowitz John L. Gross April 1995 Building and Fire Research Laboratory National Institute of Standards and Technology Gaithersburg, MD 20899 U.S. Department of Commerce Ronald H. Brown, Secreta?y Technology Administration Mary L. Good, UnderSecmtagfor Zxhnology National Institute of Standards and Twhnology Arati Prabhakar, Dinxtor Acknowledgements The survey forms used in this study were produced by Prof. Sami Masri, Rawn Nelson, David Bonowitz, Prof. Steve Mahin, Dr. Charles Thiel, Tom Sabol and Richard Holguin. The engineering firms contributing survey responses as of October 20, 1994 are The Allen Company, Brandow & Johnston, Dames & Moore, EQE/San Francisco, Englekirk & Sabol,Forell/Elsesser Engineers, John A. Martin Associates, Kariotis & Associates, KPFF, Law/Crandall, Myers Nelson Houghton, Nabih Youssef & Associates, Skidmore, Owings & Merrill and Wiss Janney Elstner. The hard work and dedication of those who completed the survey forms under considerable time pressure are appreciated. The technical review and assistance in preparing the report by Ann Bieniawski and careful review by Diana Todd are gratefully acknowledged. i Abstract The January 1994 Northridge earthquake damaged a variety of building types throughout greater Los Angeles. Perhaps the most aiming pattern of structural damage involved brittle failures at beam-to-column connections in steel moment-resisting frames (MRF’s). This damage has called into question the predictability of the behavior of steel MRF’s and the reliability of conventional connections used in California buildings over the last two decades. In response to this damage, emergency changes to the Uniform Building Code now require specific test results in lieu of reliance on a prescribed detail. This report presents results of a survey of MRF’s inspected for connection damage since the earthquake. As a catalogue of inspected MlU?’s, Iwth damaged and undamaged, the survey is intended to provide an overall view of the greater Los Angeles steel frame population, as well as a single-source building-specific record of observed conditions. Tabulated survey responses can help form a quantitative context for future research, hanrd assessment, and policy making. A computerized database was developed to track submittals, compile basic survey data, and generate the summary tables shown in the report. Principal conclusions from the survey data support the observation that MRF connection damage is not well correlated to any single structural characteristic. On the contrary, the survey data show that connection performance may be best understood in probabilistic, not deterministic, terms, with emphasis on construction and inspection quality. In other words, when the connection works, it works extremely well. But it might not work, if any link in the chain of design assumptions and construction procedures is weak. It is essential to note, however, that current survey data does not include analysis results or estimates of actual seismic demands from the Northridge earthquake. Without these, any reading of survey results must remain open to the possibility that conventional MRF connections are flawed by their basic configuration and are simply incapable of ductile behavior at high strain rates [Wiles and Campbell, 1994]. This alternate theory, which would fundamentally change the way engineers think about steel MRF behavior, can only be discarded if analysis with recorded ground motions can show that damage did not correlate with demand. Survey results reportd here show only that damage did not correlate well with design. ii Preface The survey of steel moment resisting Ilame buildings reported herein was undertaken by NIST in an effort to provide the engineering profession with an accurate characterization of the nature and extent of damage resulting from the Northridge earthquake. The motivation was to guide engineers and policy makers in hazard assessment and to provide a quantitative context for future research. The issues facing engineers and ploicy makers are indeed pressing and timely collection and reporting of survey data is deemed essential. The data collected were available from a variety of sources including design drawings, specifications, engineer’s reports and field measurements. Invariably the data collected were in English units. Conversion was required to the International System of Units (SI). Data are presented in S1 units in all tables and both S1 and English units in the text. Recorded data were often approximate (for example floor areas were recorded to the nearest 1000 ft?) and conversions were made to preserve essentially the same level of accuracy. The conversions shown below may prove useful is using this document and its appendices. S1 Unit Conversions To convert from to multiply by inch (in) . . . .. .. .. . . . . . . . . . .. .. . . . . . . foot (ft) . . . . . . . . . . . . . . . . . .. . . . . . . . . . . ft2 . .. . . . . . . . .. . .. . .. . . .. . . . . .. . . .. . . . . kip/in2 (ksi) . . . . . . . . . . . . . . . .. . . . . . . . milimeter (mm) . . . .. .. . . . . . . . . . . . meter (m) . . . . . . .. . . . . . . . . . . . . . . . . . m’ . .. .. . . . . . . .. .. . . . . . . . . . . . . . . . . . . . MPa . . . . . . . .. . . . . . . .. .. .. . . . . .. . . . . . . 25.4 0.3048 0.0929 6.895 milimeter (mm) . . . . . . . . . . . .. .. . . . . meter (m) . . . . . . . . . . . . . . .. . .. . . . . . . . m’ . . . . . . . .. . .. . . .. . . . . . . . . . . . .. . . . . . . MPa . . . . . . . . . . . . . . . . . . . . .. .. . . . . . . . . . inch (in) . . .. . .. . . . . . . .. . . . . . . . . . . . . . 0.0394 foot (ft) . . . . . . . . . .. . . . . . . . . . . . . . . . . . 3.2808 ft’ .. . . . . . . . . . . .. . . . . . . .. . . . . . .. . . . . . . 10.764 kip/in2 (ksi) . . . . . . . .. . . . . . . . .. . .. . . . 0.1450 ... m Contents Acknowledgements . . . . . . Abstract . . . . . . . . . . . . . Preface . . . . . . . . . . . . . List ofFigures . . . . . . . . . ListofTables . . . . . . . . . Abbreviations and Definitions. 1.0 . . . . . . . . . . . . . . . . . .....*.*..”.osos”o””o” ““.””=”””””” i ii . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ... . . . ..O .“””.”””.”””””.””=.000 ““””””~ . . . . . . . ..-. .””. ”””.s •“”0”=-0””0.=”~~ . . . . . . . . . . . .. ”. ”0”0”0000”0000”00 ““~ . . . . . . . . . . . . . . ...= .=”...”””*”oo*”o~ Introduction . . . . . . . . . . . . . . . . .. Damage to Moment-Resisting Fme 1.1 1.1.1 Historical Performance . . 1.1.2 Response toObwrvdDmage Survey of Available Dah . . . . . 1.2 Scope ofReport . . . . . . . . . . . 1.3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . O. . ..o. ”Occ=O”*=C Connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ...”.””””.”””” ●OOOSOOO1-l . . . . . . . . . . . . . . . . . . . . ...1-1 ...1-1 . . . 1-3 ...1-4 ““”1-5 2.0 The Survey . . . . . scope . . . . 2.1 Form . . . . . 2.2 Process . . . 2.3 . . . ..O .o.”.0”0.””.””0”0000”2-1 ...*.**.*”” ““”” ”””” ”””” ””””2-1 . . ........~.”””””””.”””” ““.2-2 . . . . . . . ...”..~”O””=C””DS”O”2-2 3.0 Characterizing theDati . . . . . . . . . . . . . . . Sources ofData . . . . . . . . . . . . . . . 3.1 3.1.1 Documents . . . . . . . . . . . . . . 3.1.2 Testing . . . . . . . . . . . . . . . . Sources ofError . . . . . . . . . . . . . . . 3.2 3.2.1 Sizeof Sample . . . . . . . . . . . 3.2.2 Nature of Sample . . . . . . . . . . 3.2.3 Scope obtesting . . . . . . . . . . 3.2.4 UT Error . . . . . . . . . . . . . . 3.2.5 Completeness ofSurveyResponses 3.2.6 Qua.lity ofSurvey Responses . . . Data Distributions. . . . . . . . . . . . . . 3.3 3.3.1 Location . . . . . . . . . . . . . . . 3.3.2 Structural Concept . . . . . . . . . 3.3.3 Structural Defiling . . . . . . . . 4.0 Characterizing the Damage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ...4-1 Damage Classes and Types.... ........~.r”....=..... . ..4-1 4.1 4.1.1 Incipient Root Cmcb~YPe We)...... . . . . . . . . . . . . ...4-1 4.1.2 Fusion Zone Damage (Types W4ad C5) . . . . . . . . . . . . ...4-5 4.1.3 Damage Class Combinations.. . . . . . . . . . . . . . . . . . . . . ..4-5 Damage Distributions . . . . . . . . . . ...-..”.=”..”””..”.. “..4-5 4.2 4.2.1 Damage Score . . . . . . . . . . . . . . . . . . . . . . ●“OOO” OO”04-8 4.2.2 Damage Ratios . . . . . . . . . . . ......*O*O*”*OO”QO”.04-9 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..g. . . . . . . . . . . . . . . . . . . ”..”.”... -“”” ””””3-1 ...=...”.””””” .“”3-1 . . . . . . . ..”” ”””” ””3-1 . . . .. * . . . . . ..2” o”3-2 . . . . ...”.””. .“”””3-2 . . . . . . ..”” . . ..s””3-2 . . . . . . . . . . . . . . ...3-3 . . . . . . . . . . . . . . ...3-3 . . . . . . . . . . . . . . ...3-4 . . . . . . . . . . . . . . ...3-5 . . . . . . . . . . . . . . ...3-5 . ..”. .o”oo”o ““”” ”3-5 o . . . ..”.””OO”” ”-3-7 . . . . . . . . . . . . . . . ...3-9 . . . . . . . . . . . . . . . ..3-11 4.2.3 4.2.4 4.2.5 No Damage . . . . . . . . . . . . . . . . . . . . ..000 ”ooo”” 004-11 Weld Damage Only . . . . . . . . . . . ..” . . . . . . . . . . . . ...4-11 Column Web Damage . . . . . . . . . . . . . . . . . . . . . . . . ...4-11 5.0 Correlating the Damage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ...5-1-. Method . . . . . . . . . . . . . . . . ...”””””””” ““”” .””” -””” ”-5-1 5.1 Non-MRF Damage . . . . . . . . . . . . . .. o. .” D.o. ..0. 00”0 “.”5-1 5.2 ScopeofInspection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..5-3 5.3 Location . . . . . . . . . . . . . . . . . . . . . . .. O. . . . ..””....” .“.54 5.4 5.4.1 Zone . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ...5-4 5.4.2 Adjacent Buildings . . . . . . . . . . . . . . . . . . . . . . . . . . . ...5+ 5.4.3 Directionality . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ...5-5 Concept Design . . . . . . . . . . . . . ...”.... . .. ”. .”” . . . . ...5-7 5.5 5.5.1 Height . . . . . . . . . . ...!”=..””” ..0..0.00.”..0007-7 5.5.2 Frame Configuration . . . . . . . . . . . . . . . . . . . . . . . . . . ...5-9 5.5.3 Rtiundmcy . . . . . . . . . ..”...... ..0.00.00..0...5-10 5.5.4 Irregularity . . . . . . . . . . . + . . . . . . . . . . . . . . . . . . ..” 5-11 DetailDesign . . . . . . . . . . . . ..........00..o”.oo.o ““””5-12 5.6 5.6.1 Yield Strength . . . . . . . . . . . . . . . . . . . . . . . . . . . . ...5-12 5.6.2 Member Size . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ...5-12 5.6.3 Other . . . . . . . . . . . . . . . . . ......*..0.*o0..5...5-14 Material &Constiction QtiitY. . . . . . . . . . . . . . . . . . . . . . . ..5-14 5.7 6.0 Conclusions and Recommendations Conclusions . . . . . . . . . 6.1 Considerations . . . . . . . 6.2 Implications . . . . . . . . . 6.3 Recommendations . . . . . 6.4 7.0 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. OO. ..............~.””””. . . . . . . . . . . . . . . . . . . . . . . References . . . . . ... . . . . . . . . . . . . . . . . . . ..o. Appendix A: SurveySummties Appendix B: Survey Forms... Appendix C: Inspection&Testing . . . . . . . . . . . . ...6-1 O.....””.. “..oo~l .o...6_2 . . . . ...” ..-..o.~2 . . . ...”” ......0~3 o.o.. ““. ”.. .” ...7-1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..A-l . . . . . . . . . . . . . . . . ...”” .....o”..oo..1-1 Criteria andReportFormats . . . . . . . . . . . . . . . C-1 Lkt of Figures Figure Figure Figure Figure Figure 1-1. 3-1. 4-1. 4-2. 4-3. Conventional Steel MRF Beam-to-Column Joint . . . Location of Geographic Zones and Recorded Ground Survey Form Da-fnage Types . . . . . . . . . . . . . . Survey Form Damage Types . . . . . . . . . . . . . . Survey Form Damage Types . . . . . . . . . . . ..*. vii . . . . . . . . . . . ...1-2 Accelerations . . ...3-8 . . . . . . . . . . . . ..4-2 . . . . . . . . . . . . ..4-3 ..”” . ..0” 4~o”4~ Lkt of Tables Table Table Table Table Table Table Table Table Table Table Table Table Table Table Table Table Table Table Table Table Table Table Table 3-1. 3-2. 3-3. 3-4. 3-5. 3-6. 3-7. 3-8. 3-9. 3-10. 3-11. 3-12. 3-13. 3-14. 3-15. 4-1. 4-2. 4-3. 4-4. 4-5. 4-6. 5-1. 5-2. Table Table Table Table Table Table Table Table Table Table Table Table Table Table 5-3. 5-4. 5-5. 5-6. 5-7. 5-8. 5-9. 5-10. 5-11. 5-12. 5-13. 5-14. 5-15. 5-16. Characteristics of Surveyed Buildings . . . . . . . . . . . . . . . . . . . . ...3-6 Summary of Survey Data by Geographic Zone . . . . . . . . . . . . . . ...3-9 Summary of Survey Data by Building Height . . . . . . . . . . . . . . ...3-10 Summary of Survey Data by Upper Floor Area . . . . . . . . . . . . . ...3-11 Number and Orientation of Frames in Surveyed Buildings . . . . . . . . . 3-12 Summary of Survey Data by Number of Bays per Frame . . . . . . . . . . 3-14 List of Ixast Redundant Surveyed Buildings . . . . . . . . . . . . . . . ...3-14 Structural Irregularities in Surveyed Buildings . . . . . . . . . . . . . . ...3-15 Summary of Survey Data by Diaphragm Type . . . . . . . . . . . . . . ...3-16 Summary of Survey Data by Nominal Steel Strength . . . . . . . . . . ...3-16 Summary of Survey Data by Exterior Column Type . . . . . . . . . . . . . 3-17 Summary of Survey Data by Girder Size . . . . . . . . . . . . . . . . . ...3-17 Surveyed Girder Types with Group 4 W14 Columns . . . . . . . . . . . . . 3-18 Summary of Survey Data by Beam Web Comection Type . . . . . . . . . 3-19 Summary of Survey Data by Girder Fkmge Weld Process . . . . . . . . . . 3-19 Summary of Surveyed Damage By Building . . . . . . . . . . . . . . . . ...4-6 Summary of Surveyed Damage by Class . . . . . . . . . . . . . . . . . . ...4-9 Surveyed Buildings with No Damage . . . . . . . . . . . . . . . . . . . ...4-11 Surveyed Buildings with Weld Damage Only . . . . . . . . . . . . . . ...4-12 Surveyed Buildings with Column Web Damage . . . . . . . . . . . . . ...4-12 Surveyed Floor-Frames With Column Web Damage . . . . . . . . . . . . . 4-13 Surveyed Buildings with Reported Lateral Set . . . . . . . . . . . . . . . ...5-2 Aggregate Damage Ratios and Score for Surveyed Buildings with Reported Lateral Set..... . . . . . . . . . . . . . . . . . . . . . . . ..5-3 Damage Ratios and Scores by Zone . . . . . . . . . . . . . . . . . . . . . ...5-5 Damage Ratios and Scores by Frame Direction . . ‘. . . . . . . . . . . . ...5-5 Damage Ratios and Scores by Zone and Frame Direction . . . . . . . . ...5-6 Damage Ratios and Scores for 3-Bay Frames by Bay Width . . . . . . ...5-7 Damage Ratios and Scores for 3-Bay Frames by Bay Width . . . . . . ...5-7 Damage Ratios and Scores in 3 to 5-Story Buildings by Floor Level . ...5-8 Damage Ratios and Scores in 11 to 14-Story Buildings by Floor Level . ..5-9 Damage Ratios and Scores by Number of Bays per Frame . . . . . . . . . .5-9 Damage Ratios and Scores by Number of Bays per Frame . . . . . . . . . 5-10 Aggregate Damage Ratios and Scores for Least Redundant Buildings . . . 5-11 Damage Ratios and Scores by Building Irregularity . . . . . . . . . i . ...5-11 Damage Ratios and Scores by Nominal Column Strength . . . . . . . . . . 5-12 Damage Ratios and Scores by WF Girder Depth . . . . . . . . . . . . . . . 5-13 Damage Ratios and Scores for W36 Girders by Bay Width . . . . . . . . . 5-13 ... Vlll Abbreviations and Definitions See also the Abbreviations and Definitions on the survey forms in Appendix B. Building Set of diaphragms laterally supported by the same set of frames or structurally separated from other diaphragms by seismic joints. Connection Intersection of one frame beam with one frame column, generally comprising a top flange connection, a bottom flange comection, and a web connection. A typical interior joinf with a continuous column and beams on both sides constitutes w connections. Damage Class TG BG TC BC A set of damage types found in the same part of a connection. Damage to the beam flange at the top of the connection Damage to the beam flange at the bottom of the connection Damage to the column flange at the top of the connection Damage to the column flange at the bottom of the connection Damage to the beam flange weld at the top of the comection Damage to the beam flange weld at the bottom of the connection Damage to the shear connection, including bolts, welds, and plates Darnage to panel zone continuity plates or welds, or ductile damage to column web or web doubler plate Cracking in column web or web doubler plate BW s Pz Cw Damage Ratio For a given set of floor-frames and a given damage class, the number of floor-frames with the given damage class observed divided by the total number of floor-frames in the set, expressed as a decimal or percentage. See Swtion 4.2.2. Damage Score For a given set of floor-fkames, a weighted sum of the number of floorframes with each of the most common damage classes, divided by the total number of floor-frames in the set, expressed as a decimal. See Section 4.2.1. Damage Type A specific pattern of yielding, buckling, or cracking. See Figures 4-1, 4-2, and 4-3. Floor-Frame The set of connections in one frame at one level. Floor Construction Types Lightweight concrete with no metal deck LC Metal deck with normal weight concrete fill MC Metal deck with lightweight concrete fill MCL w Wood diaphragm with wood or metal floor joists ix Frame System of moment-connected beams and columns generally in a single vertical plane. Geographic Zone Geographic area selected for locating buildings in this survey such that buildings within each area would be expected to experience similar ground motions. HAZ Heat affected zone of a weld Incipient Root Crack A minor buried crack in the weld metal or HAZ, detectable by UT only. Possibly a pre-earthquake phmar weld discontinuity. Interpreted by some survey engineers to include all rejectable weld discontinuities of any kind, or even all discontinuities whether rejectable by American Welding Society (AWS) criteria or not. See Section 4.1.1. MRF Moment-resisting frame. Also used to refer to an entire building whose lateral load resisting system includes MRF’s. WDR Weld Damage Ratio. For a given building, the approximate portion of all reported weld damage that is thought or confirmed by the survey engineer to be incipient root cracking, expressed as a decimal. For a set of floor-frames, the average over all the defined floor-frames of WDR for the buildings from which those floor-ffarnes come. In other words, while WDR is given for a building as a whole, for statistical purposes each floor-frame is assumed to have the same WDR. See Section 4.1.1. Stories The number of stories above ground for which the lateral load-resisting system in at least one direction is composed of steel MRF’s (i.e., does not include stories below ground or stories above ground framed with concrete frames or walls, steel ‘diagonal braces, etc.). UT Ultrasonic testing VI Visual inspection Web Connection Types Bolted connection B Welded connection w A connection which is both welded and bolted Weld Processes FCAW SMAW Flux-cored arc weld Shielded metal-arc weld x 1.0 Introduction The January 1994 Northridge earthquake damaged a variety of building types throughout greater Los Angeles. Perhaps the most alarming pattern of structural darnage involved brittle failures at beam-to-column connections in steel moment-resisting frames (MRF’s). This damage has called into question the predictability of steel MRF behavior and the reliability of conventional connections used in California buildings over the last two decades. In response to this damage, emergency changes to the Uniform Building Code (UBC) now require specific test results in lieu of reliance on a prescribed detail. This report presents results of a survey of MRF’s inspected for connection damage since the earthquake. As a catalogue of inspected MRF’s, both darnaged and undamaged, the survey is intended to provide an overall view of the greater Los Angeles steel fi’ame population, as well as a single-source building-specific record of observed conditions. Tabulated survey responses can help form a quantitative context for fiture research, hazard assessment, and policy making. 1.1 Damage to Moment-Resisting Frame Connections Although the Northridge earthquake damaged other steel assemblies such as base plates and diagonal braces, the most common damage to steel structures was in the connections of moment-resisting frames. The seismic design philosophy for MRF’s assumes that in large earthquakes frame elements will be stressed beyond their elastic range; inelastic behavior, which is useful for dissipating the energy of earthquake shaking, is allowed, but only in ductile elements. Since welds and bolts are not sufficiently ductile, the design philosophy does not allow connection failure. Instead, the role of the beam-to-column connection in a ductile MRF is to maintain its strength while adjacent beams and/or panel zones yield and deform inelastically [SEAOC, 1990]. The UBC, which is adopted with modifications by nearly all California jurisdictions as the standard for seismic design, codified this philosophy by requiring connection strength greater than beam strength. (While the UBC specified connection strength, itdid not quantify a plastic rotation demand.) Since the 1988 Edition, the UBC also included a prescribed detail which could be used without supporting calculations or condition-specific testing. The prescribed detail required beam flanges welded to the column with complete penetration groove welds and beam webs connected with welds and/or high strength bolts ~CBO, 1988 & 1991]. In fact, this conventional detail was in wide use throughout California for years before the 1988 UBC. A generic version is shown in Figure 1-1. Recent Code changes have deleted the prescribed detail calling instead for test results or calculations to demonstrate specific connection capacity [“ICBO Board... ,“ 1994]. 1.1.1 HEtorical Performance The prescribed or conventional detail was justified by tests from the early 1970’s [SEAOC, 1-1 w 1/16 = MAX GAP ~:> m DEVELOP SHEAR I u DOW%GU2-K-=+ (4F2c) (-.P TYP 4 J I I H DOUBLER PLATE (4F2) WHERE 00UBLER PLATE CONTINUES PAST STIFFENER PLATE. IT MUST HAVE THE STRENGTH TO TRANSMIT STIFFENER FORCES ALTERNATELY. STOP 00UBLER INSIDE STIFFENERS 1/2 ‘bf max WHERE REQ”O SY 4F2b BOTH-SIDE SIZE EtUJAL TO THE LARGEST OF THE FOLLOWING: SIZE REQUIREO BY 1. DESIGN TO TRANSFER PRO RATA SHARE OF STIFFENER FORCE TO WEB. 00UELER PLATE 2. THICKNESS ASSUMED FOR ORIFT CALCULATIONS 3/16 INCH. (4F2c) 3. OF COLUMN STIFFENER ANO IXIUW.EF? PLATES FIGURE G-1 Hgure 1-1. Conventional Steel MRF &am-to-Cohmm Joint Source: SEAOC, 1990 1-2 — 1990]. These tests confirmed adequate strength and pktstic rotation capacity for specific ban sizes and loading patterns. However, while most test programs on conventional connections were able to show impressive results with some specimens, all experienced some unacceptable behavior limited by non-ductile connection failures ~opov & Pinkney, 1969; Popov & Bertero, 1973; Popov et al, 1985; Popov & Tsai, 1987, Engelhardt & Husain, 1993]. A carefid reading of journal articles from 1969 through 1993, benefiting from hindsight and the Northridge experience, reveals that weld defects, bolt slippage, or other diverse factors have in some cases made the connection the most critical part of the frame, directly violating the main precept of the ductile MRF design philosophy. Since the Northridge earthquake, some leading researchers have said that none of the observed MRF connection failures can really be called unexpected @3e*ro et al, 1994]. While connection reliability can be questioned on the basis of historical test results, the performance of steel frames in earthquakes prior to Northridge has been thought to be excellent, and in practice, the steel MRF has long been considered perhaps the most reliable structural system for resisting seismic loads [Yanev et al, 1991]. Confidence in the prescribed connection detail has led to its use with a variety of member sizes, frame dimensions, shear connectors, flange weld processes, and lateral force resisting system configurations. Many initial inspections of steel frame buildings following the Northridge earthquake found only minor non-structural damage. Based on prior earthquake experience, engineers had no reason to suspect cracked welds or fractured columns hidden behind soffits, ceilings, and fireproofing. Only after a few reports of steel damage began to circulate did engineers and owners revisit buildings to perform more complete inspections. In time, these inspections revealed several distinct damage types, a number of which (e.g. weld cracks, column flange tearing, and bolt failure) had been observed in past testing programs ~opov & Stephen, 1972; Popov & Bertero, 1973; Popov et al, 1985; Popov & Tsai, 1987; Engelhardt & Husain, 1993]. Within three months, fifty steel frames had been confirmed as damaged to some degree. By September 1994, eight months after the earthquake, the estimate had grown to over 100 damaged MRF buildings. (See Section 3:2.1 for a more detailed discussion of these estimates.) 1.1.2 Response to Observed Damage As more damage was found, some building owners initiated systematic inspection and testing programs, and in many cases proceeded with engineered repairs, even in the absence of consensus standards and procedures. Other owners, whose buildings sustained little apparent damage and no substantial loss of finction, have waited for government mandates to inspect their buildings. Given the number of damaged buildings reported and estimates of the total MRF population (see Section 3.2.1), it is likely that about 100 MRF buildings in heavily affected areas have not yet been inspected for connection damage. Meanwhile, organizations and ad hoc committees in industry, academia, and government have begun studying the damage and developing new approaches to analysis, repair, strengthening, and design of steel MRF’s [AISC, 1994; SAC, Adw”soryNo. 31. A number of 1-3 . researchers and practitioners have speculated on the causes of observed damage, but there is no conclusive evidence that any one factor, whether related to design, construction, or unique “ ground motion, is consistently responsible [Sabol, 1994; Shipp et al, 1994; SEAOC Seismology Committee, 1994; Bertero et al, 1994]. Joint ventures of interested organizations have initiated testing programs to establish the causes of specific failures and the feasibility of proposed repairs. Local government responses have included emergency regulations and suspension of the Code-prescribed connection for new construction. Most significantly, the International Conference of Building Officials (ICBO) Board of Directors in September passed an emergency revision to the 1994 UK deleting the prescribed detail and calling for test results or calculations to demonstrate both strength and inelastic rotation capacity [WICBO Board...,” 1994]. 1.2 Survey of Available Data Ten months after the Northridge earthquake, inspection, testing, preliminary research, and building-specific repair were ongoing. For the steel MM? population as a whole, the following issues were among those still unresolved: ● e @ e the quantitative extent of different damage types, the correlation between damage and site factors such as ground motion, the correlation between damage and design factors such as fiarne configumtion, the correlation between damage and construction factors such as weld quality control. To address these issues, the National Institute of Standards and Technology (NIST) contracted Nabih Youssef & Associates (NYA) to compile and analyze available data on steel MRF’s inspected since the January 17 earthquake. A survey was developed for distribution to engineers who were already involved with the collection of data on the MRF connections. The goal was to make the results of this survey available to people working in all ‘earthquake-related fields. In the short term, the goal of this survey was to identify the nature and extent of observed damage, providing an accurate assessment of the situation as of November, 1994. In the long term, it is hoped that survey responses will provide insight or direction to researchers, practicing engineers, and policy makers studying the following issues, among others: o e e ● the extent to which factors that correlated with damage also cawed damage, the suitability of proposed repair and retrofit schemes, the nature of potential hazards remaining in unrepaired or undamaged frames, the relative merits of proposed code revisions and policy responses. The survey was designed to address both the short term goal of quickly collecting darnage data and the long term goal of supporting potential users with a comprehensive centralized database. The inherent conflicts between these two goals led to some revisions in survey 1-4 scope midway through data collection. Eighteen buildings were submitted on the original survey form in the first three weeks of data collection; these responses formed the basis for the preliminary report presented at an industry workshop in September, 1994 ~A, 1S94]. A revised and shortened survey form was distributed to twenty-one survey engineers in midSeptember. (Appendix B includes copies of both survey forms.) This report presents data from a total of51 surveyed buildings submitted by October 21, 1994. Survey engineers have agreed to submit data on approximately 40 more buildings as test results become available. A computerized database was developed to track submittals, compile basic survey data, and generate the summary tables discussed in this report. Not all survey items have been entered into the computerized database. 1.3 Scope of Report The data reported here represents 51 inspected MRF buildings comprising 330 inspected frames, 1290 inspected floor-frames, and 5120 inspected beam-to-column connections. Survey forms were completed by 14 different engineering offices. A damage score is calculated for each building based on the types of damage found. These damage scores are used to examine various structural characteristics of the building to establish any correlations between these characteristics and the amount of damage to the building. Section 2.0 of this report describes the survey effort in detail. Section 3.0 discusses the sources of available data and the distribution of reported buildings by location and type. Section 4.0 describes and quantifies observed comection damage. Section 5.0 discusses correlations between observed damage and factors such as building location and frame configuration. Section 6.0 presents conclusions drawn from the survey responses. 1-5 2.0 The Survey 2.1 scope The survey described in this report attempts, within the limits of available resources, to address both the short term goal of collecting damage data and the long term goal of supporting potential users with a comprehensive centralixd database. It is beyond the current scope to collect all data of potential interest on every steel MRF affected by the Northridge earthquake. The short term survey goal requires data on building identification, basic description of construction and configuration, and a list of observed damage, perhaps keyed to frame elevations. The long term goal, however, requires specific structural descriptions. When the survey effort began, five original contributing engineering firms had approximately 40 buildings with testing complete and approximately 10 more with testing in-progress. By October, 51 completed surveys had been submitted, and another 40 or so had been promised by 20 survey engineers, pending completion of testing and approval of building owners. From the beginning, the survey scope was limited in order to facilitate response. Steps taken toward this end included: ● ● ● ● ● ● ● limiting the subject buildings to steel MRF’s only, i.e. excluding braced frames, dual systems, and other steel assemblies damaged by the Northridge earthquake limiting the subject buildings to those with beam column joints visually inspected or tested, i.e. not collecting data on pote~”ally damaged buildings requiring no inspection or testing beyond that which had already been completed requiring no analysis, calculation, or numerical design check accepting responses of ‘Unknown” to avoid additional research or interviews requesting information for each floor-flame instead of each connection eliminating survey sections not directly related to building description and earthquake response, e.g. sections on ground motion, costs, repair, or potential upgrade In practice, the scope of survey responses was limited by the project schedule and a lack of available documents. In particular, because the survey engineers were generally not the original design engineers, most had no immediate access to original documents (e.g., steel mill certifications, weld specifications, structural calculations, etc.). As discussed below, the survey form was revised midway through data collection in response to these practical limitations. 2-1 2.2 Form Due to limited time and availability of documents, initial responses were substantially incomplete on issues of building design history, non-structural detailing, steel and weld properties, and building performance in previous earthquakes. Reported darnage was sometimes poorly labeled because the format for reporting it was time consuming and confusing. Additionally, the completeness of inspection, testing, and UT documentation used as the basis of survey responses seemed to vary widely. For these reasons, and with the hope of improving response, the original survey form was modified. The substantive changes put less emphasis on building history and more emphasis on the nature of post-earthquake evaluations. The procedure for reporting damage (Survey Section V) was simplified into a tabular form. While information was still requested for each inspected floor-frame, the number of affected connections in each floor-frame was no longer reported. The potential effects of this loss of robustness are discussed briefly in Section 3.2.5. Copies of the two survey forms are given in Appendix B. Eighteen buildings were surveyed with the original form, the rest with the revised form or a combination of the two. 2.3 Process The survey process for each building involved distribution of survey forms, completion and submittal of forms, database entry, quality control by telephone, and revisions as needed. Each building survey progressed on its own schedule due to ongoing inspection in various stages and a constantly expanding list of participating engineers. In most cases, survey engineers completed the forms themselves. In order to expedite submittal, however, NYA staff completed some survey forms based on interviews with and documents provided by the survey engineer. Provisions were made to protect the confidentiality of building owners and survey engineer clients. A building ID Code was selected for each building and, in this report, buildings are identified by this code only. Building, owner, and tenant rimes were not reported on survey forms. Street addresses were generally given on the written survey form with instructions to keep confidential. If so noted, street addresses were not entered into the computerized database. Instead, each building was assigned to a geographic zone, and specific building location is given only in terms of zip codes, neighborhoods, or cross streets, if at all. Despite these measures, some owners of known damaged buiIdings decIined to release information for this survey. 2-2 3.0 Characterizing the Data 3.1 Sources of Data As of October 20, 1994, fourteen engineering firms had contributed sumey data, and a total of twenty had agreed to participate. Firms were invited to participate based on their access to current building information, specifically reports of connection inspection and testing. In general, the survey engineer for a particular building had been retained by its owner to perform post-earthquake assessments and to design repairs or strengthening. In the typical case, the survey engineer was not the original engineer of record and was fkmiliar with the building only from post-earthquake inspections. In all but a few cases, specialty contractors exposed the connections and performed the visual inspections and testing; typically, the engineer performed only a building walkthrough and visual inspection of some connections. 3.1.1 Documents Though not listed in Appendix A or tracked in the current computer database, eaeh completed survey form lists the sources of data used as the basis of response. Surveys completed on the revised form (see Appendix B) also list the documents available for Mure reference. In general, the following documents were used as the basis of survey responses: Original structural design drawings Post-Northridge connection visual inspection reports “ Post-Northridge connection test reports ● Undocumented first-hand knowledge of the original building and observed damage ● ● Occasionally, the following documents were also available and cited as the basis of response: ● Original architectural design drawings Q Post-Northridge building walkthrough notes or rapid assessment report ● Post-Northridge repair drawings based on connection test reports Where the survey engineer was also the original engineer of record, some of the following documents may have been available as reference. In general, however, the following documents were not available to the survey engineer: “ Original structural calculations and design criteria c Original soil/geotechnical reports ● Stet%Welding specifications . Fabrication/Erection drawings ● Structural as-built drawings ● Weld or steel samples removed for testing 3-1 3.1.2 Testing Inspection and test reports were typically prepared by the laboratory performing the tests, not by the survey engineers. Sample inspection criteria and report forms are included in Appendix C. Specific test locations were typically selected by the engineer on the basis of visible damage, recent experience, judgement, and access. Connection inspection and testing generally involved the following basic steps: removal of finishes; removal of fireproofing to expose beam flange connections, beam web connections, column panel zone, and column flanges below the beam; cleaning of the connection, generally by wire brush only; visual inspection of members and connectors; and ultrasonic testing of beam flange welds and column flanges. Seven of the 51 survey responses were based on visual inspection only. Not counting these seven buildings, 94% of visually inspected connections were also tested. The revised survey form requested specific responses regarding the type and extent of testing; the original form did not (see Appendix B). For the 33 buildings surveyed with the revised form, typical testing involved UT only. In a few cases, magnetic particle testing and/or liquid dye penetrant testing were used to supplement the UT. Weld or base metal samples were generally not taken, and may not have been tested when they were. Despite some indications that effective UT requires removal of the backing bar and careful preparation of the weld [SAC, Session Summaries, Session 1], survey responses indicate that backing bars were seldom removed for inspection or testing. Lack of access to the outside of perimeter connections and to the top surface of beam top flanges was a common constraint on full inspection and UT. The few buildings with exterior walls or slabs removed were either under construction, vacated due to heavy damage, or temporarily vacated to perform the work. By contrast, the typical swweyed building was occupied at the time of the earthquake, reoccupied shortly after the dq~e, and continuously occupied (with limitd, temporary disruptions) during inspection ~d testing. 3.2 Sources of Error 3.2.1 Size of Sample The number of surveyed buildings required for valid correlations is directly related to the number of buildings in the steel MN? population affected by the Northridge earthquake. Following the earthquake, the Los Angeles Department of Building & Safety conducted a search of Los Angeles building permit records since 1961 for Type I and II steel framed buildings. The search found about 1200 buildings in all of Los Angeles, including about 300 in heavily damaged San Fernando Valley and West Los Angeles. This does not include buildings in separate jurisdictions such as Beverly Hills or Santa Monica. As of October, 1994, the survey included data from 51 buildings, 46 of which are in the San Fernando Valley, West L. A., or nearby Santa Monica. Assuming a current total population of 3-2 approximately 500 MRF buildings in the areas of strongest shaking, the survey represents about a 10% sample. As for confirmed &rnuged buildings, the Los Angeles Department of Building & Safety ad hoc Steel Subcommittee identified about 50 buildings with damaged eomeetions by April, 1994. By June, the Subcommittee had compiled a list of 77 buildings drawn mostly from the records of local testing firms [SAC, Program...]. In early August, five engineering firms participating in this survey indicated that they were involved with 62 buildings, most of which were not on the City’s list of 77. The combination of these two numbers corroborates oft-cited estimates of “over 100” damaged steel MRF’s [SEAOC Seismology Committee, 1994]. (This otherwise unconfirmed estimate was originally based on job records fkom the city’s two largest testing firms.) 3.2.2 Nature of Sample Local jurisdictions including the City of Los Angeles are developing inspection ordinances for steel MRF buildings [Holguin, Ordinance...]. As of October, 1994, however, all inspection and testing programs had been voluntary, usually motivated by visible frame damage, other structural damage, heavy non-structural damage, or observed MRF damage in similar nearby buildings. Since the present survey includes only inspected buildings, it is therefore likely that the sample represents the most-damaged subset of the MRF population. Mandatory inspections, however, will yield data on a broader range of MRF’s, both damaged and undamaged. - 3.2.3 Scope of Testing Survey instructions speeified no minimum scope of testing. Survey engineers were requested to report on any building with any level of connection inspection or testing, whether damaged or not. As noted above, many owners were not compdled to undertake substantial voluntary inspections in the absence of severe non-structural damage. Consequently, many buildings remain uninspected or only minimally inspected. Among the surveyed buildings, the scope of inspection and testing varied. Thirteen of the 51 surveyed buildings had complete testing at every connection in every frame. As noted above, seven buildings had no testing, but six of these had thorough visual inspection. At building ES12, preliminary visual inspection of only one floor-frame revealed cracking into the column web; results of further inspection were unavailable. Overall, of the 44 tested buildings, 25 had more than half of their floor-frames inspected and tested to some degree, and 32 buildings had at least a quarter inspected. Within each tested floor-fkame, the number of tested connections also varied, but was generally high. Three quarters of all floor-ties had more than half of their connections tested. The SEAOC Seismology Committee has recommended inspection and testing of at least 15% of all MRF connections in low-rise buildings [SEAOC Seismology Committee, 1994]. The scope of testing in nearly all of the surveyed buildings would meet this standard. Correlation 3-3 of observed damage to scope of inspection is discussed in Section 5.3. In addition to the number of connections tested, the scQpe of testing within a given connection may affect survey results slightly. In most cases, backing bars, slabs and finishes above the beam top flange, and exterior window wall obstructing the outside of perimeter frame connections were not removed. This limited the inspection and testing, espially at the beam top flange. 3.2.4 UT Error 13ecause weld damage was recorded much more frequently than any other damage class, and because most of that damage was detected only by UT, it is important to consider the reliability and consistency of ultrasonic testing. F. Robert Preece, in a monograph for the SteeI Committee of California ~reece], has written that ‘the ultrasonic method is highly dependent on the skill and integrity of the operator. ” Preece and others have noted that this dependence, coupled with the pressure of a tight construction schedule, sometimes leads a technician to accept welds based on uncertain UT readings. A common situation involves readings near the mid-length of the beam flange weld where interference from the beam web makes both welding and UT difficult. A UT indication in this area is likely to be read unconservatively, ignored, or assumed to be just the edge of the backing bar @nSon]. After an earthquake, when real damage has already been observed, the opposite situation may prevail: technicians may feel pressure to find ‘damage” or indications, erring on the conservative side. Reliability of UT and other testing is not merely a function of technician psychology, however. A root cause, say experts, is inadequate training and meaningless, inconsistent certification [SAC, Advi.rmy No. 31. Compounding the problem is a lack of training for engineers, who are largely unfamiliar with testing procedures or welding in general. In particular, engineers regularly reference AWS Ill. 1 [AWS] in project specifications, but ,. many are not taught to distinguish quality workmanslup. from, ‘fitness for purpose” or discontinuities from defects or earthquake damage. Survey responses highlighted some of these uncertainties. In some cases, weld cracks went undetected by UT until backing bars were removed for a closer look. In other cases, UT suggested weld cracks, but none could be found when the backing bar was removed for repair. The effect on survey results is largely limited to damage type WI: incipient root cracks detected by UT. As discussed in Section 4.1.1, different survey engineers reported different conditions as W 1, sometimes reporting all indications found, other times reporting only what could clearly be identified as earthquake darnage. For a given building, this variability is quantified by isolating the percentage of all weld damage that is type W1. 3-4 3.2.5 Completeness of Survey Responses As previously noted, many of the responses on the original survey form were incomplete when original architectural drawings and construction phase documents were unavailable. Except for the many buildings with unknown flange weld processes, this did not affect the general structure or damage descriptions. Two of the 51 buildings surveyed to date reported damage by frame type, not by individual floor-fkame. Consequently, that data is inconsistent and could not be used in characterizing and correlating the damage. Another completeness issue involves the survey scope. As previously noted, damage data was collected for each floor-frame, not each connection. This was done to improve response, as a connection-by-connection survey would take too much time and effort to complete, but data for a whole building or frame would not be detailed enough. As a result, if a 3-bay (connection) floor-frame is indicated as having bottom weld damage, for example, the new survey form does not record whether one connection or all six are damaged. Further, if a floor-frame has both shear connection damage (class S) and damage to the bottom flange weld (class BW), for example, it’s not clear from the survey if the two damage classes occurred in the same or different connections within the floor-frame. Finally, a fkamection frame with three different damage types all in different connections will be represented three times in a list of damaged floor-frames even though only half its connections are affected, while a similar floor-frame with the same darnage type in all its comections will be represented only once. (This last example is most significant in its effect on damage scores, defined later in the report.) 3.2.6 Quality of Survey Responses Survey responses were checked for completeness and consistency. When questions arose, responses were checked by telephone interview with the survey engineer. In general, the responses were of high quality and consistency. 3.3 Data Distributions Table 3-1 lists the 51 buildings surveyed, sortd by geographic zone. Heights and floor areas are listed to indicate building size, and the number of inspected or tested floor-frames is given to indicate the amount of data in the su~ey. Appendix A includes more detail on each building. The distribution of survey data by location, structural concept, and structural detailing is discussed below. Location data is directly related to the level of shaking experienced by each building; a given earthquake can be expected to impose similar demands on buildings in the same zone. Structural concept refers to building massing, redundancy, regularity, and other aspects of structural design usually addressed during a project’s conceptual design phase. Structural detailing encompasses the balance of structural design decisions, including materials, member sizes, and connection types. 3-5 Zone Building ID Year MRF Designed storks DM1 Floor Upper Floor No of Impected FYoor-Fhmes Area [mq Area [mq Lowfx 1970 15 5,600 2,000 5 SOM1 MW 1986 4 1,700 1,700 9 BJ05 NR 1990 11 2,700 2,300 55 BJ06 NR 1989 2 4,700 4,700 12 LCIB NR 1990 4 2,900 3 LCIE NR 1990 3 2,500 1,400 9 EQE1 Sc 1991 4 2,000 2,000 16 EQE2 Sc 1991 1 2,500 2,500 6 KPFFIA Sc 1981 2 900 900 4 BJol SM 1989 4 1,300 1$300 23 ES12 SM 1990 5 2,000 2,000 1 ES15 SM 1989 6 1,700 1,400 46 BAK so 1982 6 2,400 1,900 12 BJ04 so 1981 4 1,000 1,000 16 ES17 so 1989 3 1,400 1,400 13 JAM7482 so 1983 4 1,600 1,300 28 JAMJ484 so 1985 4 1,500 1,500 20 JAM7487 so 1979 12 1,200 1,400 41 JAM7489 so 1979 6 2,000 2,000 7 KAR3 so MNH04 so 1981 6 3,000 3,000 12 NYA550 so 1985 6 5,000 2,000 15 SOA so 1984 4 2,800 2,300 22 BJ02E Uc 1992 3 2,700 2,700 27 ES13 Uc 1984 8 700 1 17 3 Table 3-1. Characterktks of Surveyed Buildi.ngsl 1 The followingguidelinesapplyto all tablea: blank ? = not applicableor no responsewaarecordedon the survey abed = responsewaa recordedon surveyAeot aa shownbut the reporterwaauncertainaboutthe answer 3-6 BuildingID Zone WEA Uc Year MRF Designed stories LQwerFloor Upper Floor No of Inspected Area [mq Area[mq Floor-Frames 1979 4 700 1,700 24 BJ09 1982 5 8,400 4,600 50 BJlo 1990 5 4,600 4,600 13 BJll 1991 5 2,400 2,400 26 BJ18 1987 3 2,000 2,000 24 ES18 1987 25 2,600 2,500 216 1978 4 2,600 12 MNH02 WH 1984 3 2,900 16 NYA539 WH 1984 3 2,600 14 NYA544 WH 1975 13 2,400 2,400 56 18 1,800 1,800 68 1,700 1,700 19 WJE1 AC1 WLA 1984 3 ES1l WLA 1993 5 1,100 50 1988 27 1,300 10 WLA 1965 17 2,800 2,100 4 JAM7480 WLA 1983 11 3,000 2,100 14 JAM7485 WLA 1984 4 1,100 1,100 25 JAM7486 WLA 1983 13 1,900 1,500 44 MNH03AB WLA 1978 3 1,000 1,000 38 MNH03CDE WLA 1978 3 1,600 1,600 77 MNH03F WLA 1978 3 500 5(M 17 MNH03G WLA 1978 3 400 400 12 MNH03H WLA 1978 3 700 700 9 NYA577 WLA 1980 14 3,000 1,600 20 NYA591 WI-A 1970 28 2,200 2,200 16 NYA592 WI-A 1969 20 2,300 2,300 10 ES14 FE1 , Table 3-1. Characteristks of Surveyed Buildings (Continued) 3.3.1 Location Each building is located in one of nine geographic zones, as listed in Table 3-1 and shown in Figure 3-1. The zones suggest themselves according to patterns of development and the clustered nature of the 51 buildings. Table 3-2 summarizes the data of Table 3-1 for each 3-7 y ,,;;,;;;,: \ “O \ 3 6 8 12 KILOMETERS SC. \ VENTURA \ N - LAX MW LAX, El Segundo Mid-Wilshire Area NR Sc SM so Uc Northridge, Chatsworth Santa Clarita, Newhall, Valencia Santa Monica Sherman Oaks, En~ino, Van Nuys Universal City, Burbank Woodland Hills, Canoga Park West L. A..-, Brentwood. –, Centmv, Citv , WLA Figure 3-1. Location of Surveyed Buiklings and Recorded Ground Accelerations Source: CSMIP 3-8 zone. The 15 buildings in zone WLA are the most dispersed and ean therefore be expected to . represent the most diverse soil conditions and ground motions. The buildings in zones WLA and SM could be considered together based on their relative proximity, but are listed separately to indicate separate political jurisdictions. Three zones, SO, WH, and WLA, account for 36 of the 51 surveyed buildings, but five of the zone WLA buildings are separate superstructures on a shared si~, and thr=- of the zone WH buildings are structurally independent wings of a single complex. No zone I Year] of I ““s ‘-”I l== 1970 LAX I 15 I 15 I 2,000 I 2,m Mw NR 4 79 1989 Sc 3 26 1981 SM 3 70 1989 1990 4 6 1,300 2,000 so 11 189 1979 1989 3 17 1,000 3,000 Uc 3 1979 1992 3 8 700 2,700 1991 3 2s 1,800 4,600 I 52 I 1993 I 3 1281 400 I 2,3W * Table 3-2. Summary of Survey Data by Geographic Zone Figure 3-1 zdso shows recorded peak accelerations, as published by CSMIP [CSMIP]. The nearest recorded horizontal acceleration is less than 0.33g for only two zones, MW and LAX, which are represented in the survey by one building each. However, four buildings in the eastern portion of zone WLA are nearer to the station recording 0.27g peak horizontal acceleration than to the Santa Monica station recording 0.93g. Downtown Los Angeles, near recorded peak horizontal accelerations of 0.32g and 0.49g, currently has no buildings in the survey. 3.3.2 Structural Concept Table 3-3 shows the distribution of survey data by buildlng height. Three- to six-story buildings account for 33 of the51 buildings surveyed, but they differ in size, with floor areas as small as 400 square meters (4500 square feet) and as large as 4600 square meters (50,000 square feet). Floor diaphragm size is more consistent among the taller buildings but any study of the tall buildings as a class will be dominated by building ES18 whose 216 inspected and tested floor-frames represent the most of any surveyed building. The average floor 3-9 ——-—— ----— diaphragm size for all buildings and floor-frames in the survey is about 2000 square meters (21,000 square feet), a figure which was practically law among office developers in the early 1980’s [Garreau]. Thus, the surveyed buildings can be considered representative of the larger MRF population at least in terms of floorplate. Tables 3-1 and 3-3 show that this floor area can be found in buildings of almost any height. Table 3-4 shows the distribution of surveyed buildings and floor-frames by typical upper floor area. No of ~h@s Flr-Flllls stories Maxm Minm Area [IU7 Area[mq 1 1 6 2,500 2,500 2 2 16 900 4,700 3 12 275 400 2,900 4 11 198 1,000 2,900 5 5 140 1,100 4,600 6 5 92 1,403 3,000 8 1 1 700 700 11 2 69 2,100 2,300 12 1 41 1,400 1,400 13 2 100 1,500 2,4(KI 14 1 20 1,600 1,600 15 1 5 2,000 2,000 17 2 7 2,100 2,100 18 1 68 1,800 l,fmo 20 1 10 2,300 2,300 25 1 216 2,500 2,500 27 1 10 1,300 1,300 28 1 16 2,200 2,200 Table 3-3. Summary of Survey Data by Building Height Structural redundancy is considered essential to reliable seismic behavior ~reeman, 1987; Naiem, 1989; SEAOC, 1990] and in the wake of observed Northridge damage, increased redundancy has been suggested as a method to improve connection performance ~ley and Saunders, 1994; SAC, Session Summaries, Session 4]. Redundancy can be achieved by using multi-bay frames, providing several frames in each principal direction, distributing the frames in plan to minimize the effects of irregularity and torsion, or by combining these and other measures. 3-1o Floor Area [mq <700 No of Bk@ 38 13 I 313 700-1,500 14 324 2 27 1,500-2,200 16 359 3 18 2,200-3,000 13 479 1 28 ~3,000 4 87 2 6 Table 3-4. Summary of Survey Data by Upper Floor Area For each building, the number of frames in each direction is given in Table 3-5. As shown, nezirly all the surveyed buildings were reported as oriented with N-S and E-W principal directions. The number and average width of bays in each building was not compiled for this by number of bays and average bay survey, but the overall distribution of inspecredties width is given in Table 3-6. The 3-bay frame is most common, showing up in 31 of the51 surveyed buildings, but bay widths range widely, from one to three times a typical story height of 3.7 meters (12 feet) . Floor area tributary to a given frame or bay can be considered a quantitative measure of redundancy, but such detail was not compiled in this survey. For purposes of correlating observed damage to redundancy, the least redundant buildings can be identified as those with fewer than three frames in a given direction and only one or two bays in those frames. The buildings and floor-frames that meet these conditions are identified in Table 3-7. Structural irregularities require special attention in design because they are at odds with the assumptions inherent in basic code procedures. Whether the irregularities in surveyed buildings were properly considered during design is unknown. For purposes of correlating observed damage to regularity, the irregular conditions in surveyed buildings are identified in Table 3-8. Twenty-nine of51 buildings had irregularities of some kind; eight had both vertical and plan irregularities. The most common irregularities, reentrant comers and significant changes in mass from floor to floor, were due to setbacks in the building envelope, a common architectural design feature of 1980’s office buildings [Garreau]. 3.3.3 Structural Detailing Table 3-9 shows the number of surveyed buildings and inspected floor-frames for different floor diaphragm types. Wood and concrete diaphragms are fundamentally different in terms of seismic behavior because wood floors are generally much lighter, do not act together with frame beams as composite members, and are less rigid and therefore much less prone to 3-11 Building ID N-S E-W DM1 2 2 SOM1 3 3 BJ05 4 2 BJ06 2 3 LCIB LCIE 8 11 EQE1 2 2 EQE2 3 3 K.PFFIA 2 2 BJol 3 ES12 NE-sw NW-SE 6 8 2 5 4 2 Remarks 4 ES15 BAK 2 3 BJ04 2 2 ES17 3 3 JAM7482 3 4 JAM7484 2 2 JAM7487 2 2 JAM7489 4 5 KAR3 2 2 MNH04 4 4 NYA550 5 5 SOA 4 6 BJ02E 6 4 ES13 1 WEA 2 4 BJ09 8 8 At floors1-4,2 2-bayNWSEti. l-by NWSEframes. At firs 5-7,4 Actual mrnpaw directions need to be confirmed. At floors 5-7(rf), 2 NS, 2 EW. 1 1 Table 3-5. Mmber and Orientation of Rames in Surveyed Buildings 3-12 BuildingID N-S E-W BJlo 4 4 BJll 4 4 BJ18 3 3 ES18 3 3 MNH02 4 2 NYA539 6 6 NYA544 2 2 WJE1 2 2 ACI 4 4 ESI1 5 5 ES14 2 2 NE-sw NW-SE 1 2 Remarks NOTE:NS frames“bend”in plan, are not in single verticalplane. EW tlames differ in orientation by about 40 degrees, but resultant is normal to resultant of NS frames. FE1 o 2 JAM7480 4 4 JAM7485 2 3 NS direction is Shear Wall System. JAM7486 2 2 MNH03AB 6 8 MNH03CDE 14 13 MNH03F 3 4 MNH03G 2 2 MNH03H 2 3 NYA577 6 2 NYA591 o 2 NYA592 2 2 At ground, including small fiamea under low roo~, 8 NS, 4 EW, 2 NWSE. Table 3-5. Number and Orientation of Frames in Surveyed Buildings (Continued) 3-13 —-—— No of &y.$ No of Bldgs Flr-Frms Min TyP WY AvgTyp &Y Repmented Width [m] Wldtb [m] Max TyP &Y Width [m] 1 15 207 5.5 9.5 14.0 2 19 450 3.4 7.0 10.4 3 31 309 4.6 7.6 12.2 4 20 135 4.0 7.3 9.8 5 12 124 4.0 8.5 9.8 6 4 19 4.9 5.2 8.8 7 3 25 4.6 4.9 5.2 8 1 1 8.8 8.8 8.8 9 1 4 7.6 7.6 7.6 11 3 16 6.1 7.0 7.6 Table 3-6. Summary of Survey Data by Number of Bays per Frame h BuiMingID zone Direction K.PFFIA Sc NS 2 2 2 ES15 SM NWSE 10 2 2 II BJ04 Iso IEW[6[ 2 No OfhyS I 2 BJ04 so NS 6 2 2 JAM7484 so EW 10 2 1 JAM7484 so Ns 10 2 1 21 1 llwEAIUCINsl II No of FHIE Flr-Frms 81 W3E1 EW 34 2 2 WJE1 NS 34 2 2 JAM7485 WLA I 8 I 2 I 2 Table 3-7. List of Least Redundant Surveyed Buildings 3-14 Plan Irregularities Building ID Vertkal Irreguhwitiea DM1 Y possiblesott story & geom irreg at setbackabove pO&umbase. N BJ05 Y possiblemassirreg at tkwr 9 setback. Y out-of-planeoffset8at fkwrs 2 and9. EJ06 N Y diaphdiswnt at 15x30 m atrium opng. LCIB unknown Y apparmt diaphdunt repoltedas unknown at atrium,but LCIE unknown Y apparent merit caners, but repoxted as Unknow EQE2 N Y meat eomec L-shapedfloors. ES12 N Y reentcomers E815 Yin plane discontinuity at floor 5. Y out-of-plane offaels at floor 5. BJ04 Y possible geom irreg at floor 3 fhne 2 setback. N ES17 N Y reent comers: L-shaped floora. JAM7482 N Y possible reent comers JAM7487 Y possible soft story at tall columns, floor 2 & 3 mezzaninelpartial floor Y meat comers& d~ph diseont @ partial floors 2 and 3. JAM7489 N Y reent eomera: T-shape floors NYA550 Y mass & geom irreg at floor 4 setback. Y reentrant comer SOA N Y reent comers WEA Y mass irreg N BJ09 Y possible mass irreg at floor 3 setback. Y meat eomcm at floor 3 and above. BJ18 N but notediscontinuous top story columnslandingmidspan on floor 3 girders. Y reent comer, L-shaped flmrs. E!N8 N Y meat eomera. MNH02 N Y reent comers NYAS39 N Y reemtrant comer (L-shaped diaphragm) AC1 Y possible geom irreg at setbacks. Y possibic reed comers Esll Y mass irreg at floor setbacks. Y torsional irreg, ree@ comers, daph discontinuity repotted. ES14 N Y recnt comers FEl N Y out-of-plane offset at base JAM7480 Y mass geom irregs due to many setbacks Y possible reent comers JAM7486 Y possible mass irreg at floor 6 setbacWdeck type change N N Y man wmers Y mass & groin irreg at floor 2 & 3 low roof setbacks. N MNH03CDE NYA577 Table 3-8. Structural Irregularities in Surveyed Buildings 3-15 Floor Construction I No of Bhigs I 1%-Frms I MiIIFlr Area [dl I M$UL ~ AIW [mq 10 2,300 2,300 673 1,300 4,700 48 1,700 2,400 19 299 700 4,600 MCL/MC 1 46 1,400 1,400 w 8 214 400 1,700 LC 1 MC 19 MC or MCL? 3 MCL Table 3-9. Summary of Survey Data by Dmphragm Type torsional response. Most of the buildings with metal deck and concrete fill also have steel studs at nominal spacings, probably intended for shear transfer only. Because of the variety of beam depths and deck orientations all using the same typical stud spacing, it is difficult without analysis to characterize beams as composite with any reliability. Table 3-10 shows the distribution of survey data by speeified column and beam yield strengths. Some engineers specify Grade 50 columns in combination with A36 beams to help ensure a ‘strong-column-weak-beam” design. However, the actual relative strengths of A36 and A572-Gr50 may vary widely, and the two steal grades have markedly different yield/tensile strength ratios ~amburger and Frank, 1994]. These uncertainties can affect the states of stress and strain in frame members and welds. As shown in Table 3-10, the combination of A36 steel in both the columns and the beams is represented by more surveyed buildings, but the combination of A572-Gr50 steel in the columns and A36 steel in the beams is represented by more of the reported floor-fizunes. Roth combinations appear in buildings of varying ages and heights, although the average building height of all floor-frames with the combination of A572-Gr50 steel in columns and A36 steel in beams is significantly higher than that of the floor-frames with the combination of A36 steel in both columns and beams. w No of A572-Gr50 II A572-G50? Flr-Frms 2 A36 Bldg Height [Stork] Olltest Newest Shortest Avg Tallest 5 1981 1984 2 3 8 1 14 1983 1983 11 11 11 A36 28 540 1%5 1991 1 6 28 I A36 19 705 1970 1993 2 14 27 I A36? 1 26 1991 1991 5 5 5 A36 ~ Year IMgned Bldgs Table 3-10 Summary of Survey Data by Nominal Steel Strength 3-16 Table 3-llgives aapprofimak (memkrsim &tiwasnot mmplekfor mmebuildings) count of surveyed buildings and floor-fmmes with different types of exterior columns. The distribution of interior column types is similar, but with fewer box columns. The AISC [AISC, 1989] Group 3 and 4 W14 sections dominate the survey. Table 3-12 gives approximate counts for each nominal beam depth (built-up beams are not included). Typical Exterior No of Bk@ Fir-- Year Dedgned Column Oldest I Newest Bldg Height [stones] shortest Tallest 1 ~X Or Built-Up I 4 118 1975 1984 3 13 W8 I 4 22 1978 1978 3 3 W12/14 Group 3 I 22 171 1970 1991 1 17 W12/14 Group 4 I 25 446 1970 1993 3 27 14 67 1981 1988 2 27 15 91 1979 1992 2 11 W14 Group 5 W21124127 Table 3-11. Summary of Survey Data by Exterior Column Type Typical Girder No of Bldgs Flr-Frms Year Desiined Oldest Newest Min Bay Avg &y Max Bay [m] [m] [m] W14116 6 48 1978 1983 4.6 5.8 8.5 W18 9 46 1970 1990 3.7 6.1 12.2 W21 12 112 1970 1990 3.4 5.5 12.2 W24 23 135 1970 1992 4.0 7.0 10.4 W27 19 56 1970 1993 4.9 7.9 12.2 W30 20 106 1970 1992 4.0 7.6 12.8 W33 20 174 1970 1993 4.9 8.5 12.8 W36 30 533 1970 1993 4.6 7.9 14.0 Table 3-12. Summary of Survey Data by Gwder Size (VW’@den only) Clearly, sections from 610 to 914 millimeters (24 to 36 inches) deep are used in a variety of conditions. As for combinations of column and beam sizes, Table 3-13 shows the different typical beams found in combination with Group 4 W14 columns. The W36X150-230 beams are most common. 3-17 . No of Bldgs Typical Gkder I W18X26 W33X130 I1 1 W33X141 I , I 1 I 2 I, 4 1 2 II 2 I 3 I 11 I W33X152 1 II I W33X201 2 5 I 1 1 W33X221 1 2 W24X146, W33X130 1 1 W33X241 2 12 W24X162, W36X135 1 1 W33X280 1 3 1 W36X135 W21X83-W24X131 I I , II W24X62 I II W24X68 1111 , I 1 I 3 I 5 W36X150 6 45 1 2 W36X160 4 24 W27X146 2 6 W36X170 8 37 W27X84 2 3 W36X182 W27X94 2 2 W36X194 8 46 W3OX1O8 3 3 W36X194, BU36 1 1 2 W36X194, BU48 1 1 I 2 W36X21O 5 48 I 2 W36X230 8 51 W36X245 4 24 1 II I W30X116 II W30X124 1 6 1 1 12 ‘ 1 11 3 I 4 I 1 W33X118 I t I W36X260 I W30X99 35 1 1 W30X191, W36X150 I II I 1 II I W24X76 W3OX1O8, W30X 116 4 s 1 I FlrFlms I 4 I 11 I 1 I Table 3-13. Surveyed Girder Types with Group 4 W14 Columns Table 3-14 shows the data distribution for different web connection types. The correlation with age is clear: the oldest buildings have all-welded beam webs, the newest have bolted webs with supplemental welds as required by the UBC since 1988, and most of the surveyed lyplv.al mills INru,tu **.-- . . ...------4-= ‘+----- . ** are most common. 3-17 * . *Ann*- 1----- L -1.- --1.. x?-... .L..4 *ha recent buildings with W13type connections generally have supplemental welds or@ where required by Code, that is at the lightest sections within each beam depth group. Year Des&led Web COM Type No of Bklgs Flr-Fhns B 37 unknown oldest Newest 1027 1975 1990 2 26 1989 1989 w 4 35 1%5 1970 WB 8 202 1988 1993 Table 3-14. Summary of Survey Data by Beam Web Connection Type Year Desiined Flange Weld Pr- No of Bklgs FCAW oldest Newest 8 1%5 1993 389 SMAW 6 1978 1990 83 SMAW? 3 1984 1990 86 unknown 34 1%9 1992 732 & b- Table 3-15. Summary of Survey Data by Gmder Flange Weld Process Table 3-15 shows the data distribution for different beam flange weld processes. Because weld processes are frequently not shown on structural drawings, 34 of the 51 survey responses either did not report a weld process or reported it as unknown. 3-19 4.0 Characterizing the Damage 4.1 Damage Classes and Types The survey form described MRF connection damage with 24 different types, as shown in Figures 4-1 through 4-3. For reporting purposes, beam flange, column flange, and weld damage were further identified as occurring at either the top or bottom of the connection. (See Abbreviations and Definitions for damage class abbreviations.) In addition, narrative descriptions of non-structural damage and non-MRF structural damage were provided, and overalI structural damage in each building was categorized by the survey engineers as None, Isolated, or Widespread. These descriptions are given for each building in Appendix A. 4.1.1 Incipient Root Cracks (Type Wl) The most commonly observed damage was in bottom flange welds (class BW), and a large portion of these conditions are small or incipient root cracks detected by UT (type Wl). No descriptions or definitions beyond those in Figure 4-3 were provided to the survey engineers. Instead, many survey engineers relied on definitions provided by their testing lab, examples of which are given in Appendix C. Although procedures and acceptance criteria became more detailed and standardized as more buildings were inspected, UT results for many buildings were submitted without complete descriptions of the testing scope and findings. If low rejection rates are achieved initially, a large project can have up to 75 % of its flange welds not UT’d during construction; if rejectable welds exist, they may not be found. And, as discussed previously, UT procedures call for significant judgement, which may err on the unconservative side during construction but on the conservative side during post-earthquake inspections. Consequently, there is some question as to how many root discontinuities and rejectable welds were actually caused by the earthquake. For the survey, some engineers reported all discontinuity signals as W1 damage, even if they would normally be acceptable for new construction, on the theory that they could be “small root tears” worth investigating further (see Appendix C). Others reported only rejectable conditions. Still others reported only conditions clearly identified as earthquake damage. (Note that the typical standard for ultrasonic testing of welds, AWS D 1.1 Chapter 8, is primarily intended to check workmanship, not ‘fitness for purpose.”) damage type was so prevalent and variously defined, and because damage statistics are reported here by class not type, it was necessary to distinguish W 1 conditions from other weld damage. To do this, the survey form asktxl survey engineers to estimate the percentage of all weld damage considered to be type W1. Although definitions of W1 ‘damage” varied among the many survey engineers, the amount of definite weld damage caused by the earthquake can be approximated by multiplying the number of floor frames in damage classes for top weld (’I’W)damage or bottom weld (INN) damage by the factor (1-WDR), where WDR is the weld damage ratio. This approach was used for computing damage scores. Because this 4-1 SURVEY OF STEEL MRF BUILDINGS AFFECTED BY THE JANUARY NORTHRIDGE EARTHQUAKE SECTION V 1994 COlltbWSd R5FERENCE SCHSDULS OF DAMAGE WPES [SeeReferanceDetailsbelow for pictorial description.) G GIRDER DAMAGE buckled flange GI yielded flange G2 flanga tearout near weld G3 flange crack outside NAZ G4 G COLUMN FLANGE DAMAGE inapieht (detsctad by WI complete flange tearout or divot C2 full or partfal cross-flange crack in HA2 C3 C4 fuIl or pardal cross-flange crack outside i=lA2 Isnreltar flange tearing C5 cl w FLANGE WELD DAMAGE incipientcrack,aaPaciailY at weld root (datactad by UT crackthroughWeldmetal,fullor partialwidth of flange fracture at girder intatface WI W2 W3 W4 s flange-ck fractureal columnintarfa~e SHEAR CONNECRON DAMAGE S1 column to web or columnto sheartab weld crack wab to shear tab Suppiemettta! weld crack S2 web or ahoar tsb crack,SSPaCialfY throughboltholas S3 web or ahear tab deformation, especially at holes. 34 loose, damaged, or mi$sing bolts; fayhg surfaces out-of S5 CORt8Ct . Pz PANEL PI P2 P3 P4 Cw COLUMN WEE DAMAGE P5 partial depth crack in column web or doubler plate (extension of C3 or C4) P6 fuil or near full derxfrcrackin column web or doubler plate ZONE DAMAGE fracture, buckle. or y!eld of continuity plate crack in continuity plate welds buckle, yield, or ductile deformation of doubler plate or column web crack in doubler plate walda Figure 4-1. SuNey Form Damage Types (See Appendix B) 4-2 SURVEY OF STEEL MRF BUILDINGS AFFECTED BY THE JANUARY NORTHRIDGE EARTHQUAKE SECTION V 1994 OOtlthld REFERENCE O~AIL (See Reference Sohedule ebovefor dsmegetype descriptions.] > REFERENCED~AIL MRF JOINT DAMAGETYPES NOW SEE REFERENCESCHEDULEFOR DESCRIPTION Figure 4-2. SurVeYForm Damage Types (See Appendu B) 4-3 SURVEY OF STEEL MRF BUILDINGS AFFECTED BY THE JANUARY NORTHRIDGE EARTHQUAKE SE~ON lbkringfualwlo: f%-m -* 1994 orig Oetw F4wn o- PagC V continued for damage WPO cfescriPtions.) REFERENCE OErAIL (See Reference Scheduia ahve REFERENCE ‘NOTE: DETAIL MRF DAMAGE TYPES SEE REFERENCE SCHEDULE Figure4-3. FOR DESCRIPTION Survey Form Damage (See Appendix B) 4-4 Types 4.1.2 Fudon Zone Damage (Types W4 and C5) The survey damage types shown in Figures 4-1 through 4-3 were grouped into classes according to the part of the connection most affected. Damage types W3 and W4 occur at the interface of weld and parent metal. These types were grouped with class W because damage at the weld interface is generally considered a fimction of inadequate welds, specifically poor fusion resulting from insufficient preheat or poor workmanship. If damage near the interface is not visible, it is difficult to distinguish clearly by UT whether a crack occurs in the weld or parent metal. Consequently, damage types W4 and C5 can be confused with each other. In some cases, darnage type C2, a tear in the parent material, can also be confused or combined with type W4 or C5. Different survey engineers may have reported this kind of darnage differently; some reported uncertain or combined types as damage to both weld and column. For survey purposes, this may affect damage statistics compiled by class, as W4 and C5 damage are in different classes. However, the net effect on conclusions drawn is not expected to be significant. 4.1.3 Damage Class Combinations Some damage classes always appear to occur together in the same connection. However, because the survey reports damage in each floor-frame, not each connection, these combinations cannot be quantitatively confirmed. The related damage classes include: Q Top weld (lTV) darnage occurs in 213 floor-frames in 25 buildings. About 75% of those floor-frames also have bottom weld @w) damage. TW occurs by itself in only 48 floor-frees in six buildings. . Shear (S) damage occurs in 44 floor-frames, always in combination with either bottom weld (NV) damage or bottom column flange (13C)damage, and about half the time with both. ● Column web (CW) damage, as expected, always occurs in combination with column flange cracking. In 46 of 47 cases, the crack is at the bottom of the comection. In 33 floor-frames, column web (CW) damage was observed without damage to the shear connection. 4.2 Damage Distributions Table 4-1 summarizes the number of inspected floor-frames with each class of damage in each building. The buildings are listed by zone for comparison with Table 3-1. Table 4-2 summarizes the incidence of damage, showing the number of buildings and floor-frames in which each class was found at least once, as well as the range of conditions in which each class is represented. Clearly, each damage class is represented in buildings of various ages and heights and in frames with various numbers of bays and bay widths. 4-5 Building ID Damage Class Zone WDR Flr-Frms TG BG TC BC Tw 5 0 0 0 0 BW s Pz Cw 0 0 0 0 0.00 6 0 0 0 0.33 DM1 LAx SOM1 MW 1.00 9 BJ05 NR 0.70 55 0 0 1 15 3 35 0 0 0 1.10 BJ06 NR 0.75 12 0 0 0 3 1 9 2 0 3 2.21 LCIB NR 0.05 3 0 4 0 12 9 13 2 1 4 LCIE NR 0.00 9 0 0 0 6 2 13 0 1 3 EQE1 Sc 0.00 16 0 4 0 16 0 0 8 0 7 4.31 EQE2 Sc 0.00 6 0 0 0 5 0 0 0 0 5 4.17 KPFFIA Sc 0.60 4 0 1 0 0 0 3 0 0 0 0.68 BJol SM 0.90 23 0 3 1 4 11 21 2 0 0 1.36 ES12 SM 0.00 1 0 0 0 0 0 1 5.00 ES15 SM 0.30 46 0 0 0 11 44 0 0 0 2.51 BAK so 0.00 12 0 0 0 0 10 0 0 0 1.25 BJ04 so 0.30 16 0 0 0 1 1 14 0 0 0 1.25 ES17 so 0.00 13 0 0 0 0 0 3 2 0 0 0.65 JAM7482 so 0.50 28 0 0 2 6 8 16 0 0 1 1.39 JAM7484 so 0.50 20 0 0 1 3 15 16 4 0 1 2.40 JAM7487 so 1.00 41 0 0 0 1 0 11 0 0 0 0.18 JAM7489 so 7 0 0 0 0 0 0 0 0 0 0.00 KAR3 so 3 0 0 0 3 0 0 0 0 0 2.00 MNH04 so 12 0 0 0 0 0 0 0 0 0 0.00 NYAS50 so 1.00 15 0 0 0 0 0 4 0 0 0 0.13 SOA so 0.00 22 0 3 0 8 1 9 6 0 0 1.95 BJ02E Uc 0.50 27 0 0 1 16 11 23 4 7 5 3.30 ES13 Uc 1.00 1 0 0 0 1 0 1 1 0 0 4.50 WEA Uc 0.00 24 0 0 0 5 2 6 0 0 5 1.54 BJ09 WH 0.90 50 0 0 0 1 1 18 0 0 0 0.27 0.00 0 Damage score 0 0 1 34 Table 4-1. Summary of Surveyed Damage By Building: Aggregate Damage Score & Number of Floor-Frames in Each Damage Class 4-6 Building ID zone Damage Class WDR Flr-Fnns TG BG TC BC Tw BW s I?z Cw Damage score 13 0 0 0 0 0 0 0 0 0 O.(X3 1.00 26 0 0 2 7 8 15 0 0 0 0.98 m 0.75 24 0 0 0 2 1 14 0 0 0 0.64 WH 0.80 216 0 0 0 0 74 77 0 0 0 0.49 WI+ 0.20 12 0 1 0 7 0 6 0 2 6 3.32 MNH02 WH 0.75 16 0 0 0 4 0 9 0 4 4 1.67 NYA539 WH 1.00 14 0 0 0 0 6 13 0 0 0 0.68 NYA544 WH 0.50 56 5 9 0 9 0 25 9 0 0 1.09 WJE1 WH 0.00 68 0 0 BJlo WH BJll WI-I BJ18 ES18 AC1 WLA 0.00 19 0 0 6 0 — 1 0 2 0 ESI1 WLA 0.00 50 0 0 0 3 ES14 WfLA 0.10 10 0 0 0 FE1 WLA 4 0 0 JAM7480 WLA 0.33 14 0 JAM7485 WLA 0.40 25 JAM7486 WLA 1.00 MNH03AB WLA MNH03CDE WLA 13 - 0 - 0 0 - - 0.46 ~ 16 0 0 0 1.47 1 7 2 0 0 0.44 0 5 6 0 0 0 1.54 0 0 0 0 0 0 0 0.00 0 1 9 2 12 1 0 1 2.81 0 0 0 9 11 17 1 0 0 2.03 44 0 0 0 0 1 9 0 0 0 0.11 0.00 38 0 0 0 0 2 5 0 0 0 0.28 0.00 77 0 0 0 .1 0 8 0 0 1 0.22 MNH03F WLA 0.00 17 0 0 0 0 0 3 0 0 0 0.26 MNH03G WLA 0.00 12 0 0 0 0 0 1 0 0 0 0.13 MNH03H WLA 0.00 9 0 0 0 0 0 0 0 0 0 0.00 NYA577 WLA 1.00 20 0 0 0 0 2 19 0 0 0 0.53 NYA591 WLA 1.00 16 0 0 0 0 1 2 0 0 0 0.09 NYA592 WLA 10 0 0 0 0 0 0 0 0 0 0.00 Table 4-1. Summary of Surveyed Damage By Building Aggregate Damage Score & Number of Floor-Frames in Each Damage Class (Continued) 4-7 4.2.1 Damage Score The final column of Table 4-lgives aroughdamage ”score” foreach building. The ratios of damaged floor-frames to inspected floor-frames for the most common damage classes are weighted and summed as follows (FF = total inspectedtested floor-fi-ames): Damage Score = (TW+BW)/FF + + + + (TW+BW)(l-WDR)/FF S/FF BC/FF CW/FF x x x x x 0.5 1.0 2.0 2.0 3.0 Thus, a single floor-flame with no damage would score O; with only incipient root cracking in bottom welds, 0.5; with complete bottom weld fracture only, 1.5; with incidence of all five of the most common damage classes, 10. For groups of floor-frames, the score reflects the ratios of damaged to inspected floor-frames, so that a building with widespread weld damage can score higher than one with isolated flange tears. Note that this scoring system takes no account of the number of inspected, tested, or damaged connections within a single floor-frame, nor the number of inspected floor-frames within a single frame. In particular, because data is available only for individual floor-frames, not individual connections, comparison of scores for different groups of floor-frames is only valid for sufficiently large groups. (See Section 3.2.5 regarding completeness of responses.) Also, note that the effective weights for shear (S) and column web (CW) damage are actually higher than they appear because shear (S) and column web (CVJ) damage always occur in combination with other classes, as noted above. This scoring of observed dbnage is tentative, experimental, and intended only as a check on conclusions drawnf?om raw numbers of damagedjloor-j?wmes. The weights are based on engineering judgement as to the relative severity, structural and financial, of each damage class. Different weights may be equally valid. No study of statistical sensitivity has been made. Damage scores for each building are given in Table 4-1. The scores for buildings LCIB and LCIE must be ignored, as their surveys reported damage for each frame type, not for each floor-frame. As shown in Table 4-1, the minimum score is O, while the maximum is 5.0, reflecting the small number of inspected floor-frees in building ES12. Among buildings with six or more inspected floor-frames (for example a 3-story building with one fkame inspected in each direction), the minimum score is O, while the maximum is 4.31. Excluding LCIB and LCIE, the aggregate score for buildings with six or more inspected floor-frames is 0.98, or approximately 1.0, using a survey-wide average WDR of 0.50. The mean score for this subset of 43 buildings is 1.15, or rounded to 1.2, and the standard deviation is 1.14. Thus, any sufficiently large group of floor-frames with an aggregate damage score greater than 1.15 +1. 14=2.29, or roughly 2.3, has significantly more than average damage. Seven of the 43 ‘well-inspected” buildings meet this criterion. 4-8 4.2.2 Damage Ratios Damage ratio, expressed in decimal or percentage form, is used here to mean the simple ratio of damaged floor-frames (or buildings) to total floor-frames (or buildings). From either a building or floor-frame perspective, the most common damage is seen from Table 4-2 to be in beam flange welds (classes TW and BW). Compared to the next most common damage class, column flange tearing, weld damage was observed in three times as many floor- Damage clam II No of Bhigs Full Survey ] TG 51 FlrFnns ~290 Year Desiined Bldg Ht [stories] Min # Mu# Bays Bays Oldest Newest Shortest Tallest [ 1966 I 1994 I 1 I 28 11151197611976113113 II Min Bay M.ax Bay Wldth[m] Width[m] 1 11 3.4 14.0 5 5 9.8 9.8 2 5 4.0 9.8 1 4 5.2 11.9 1 2 I 28 1 2 I 28 1 11314411976119941 2 113 1 PZ 15115 3 14 2 Cw 11414711979119941 1 Ill 1 6 1 11 TW 1251213 BW I s 4ny Damsge I 40 44 11970119941 1552 I 19701 1994 I 11985119941 1629 I 1970 I 1994 I 1128 I 3.4 I 3.4 45 661 1966 1994 1 28 1 Weld only 36 426 1970 1994 2 28 1 >Weld only! 32 I 186 I 1976 I 1994 I 1!18 1 11 I 11.9 I 14.0 , 1 No Damsge I 3.4 I 14.0 * TabIe 4-2. Summary of Surveyed Damage by Class frames. About 41% of all inspected floor-frames had some bottom weld (BW) damage, and about 17% reported top weld (TW) damage, although Table 4-1 suggests that perhaps half or more of this is incipient root cracking only. Cracking or tearing in the cohxmn flange at the bottom of the connection (class BC) also occurs in about 12% of inspected floor limes. Column flange cracks extended into the column web (class CW) in 47 floor-ftames in 14 different surveyed buildings. The other damage types appear in far fewer floor-frames and buildings. Top beam and top column flange damage is reported most rarely; this maybe due in part to limited access to the top surface of the beam top flange. 4-9 The damage classes labeled “No Damage” and “Weld Onlyw in Table 4-2 require some explanation. First, note that the “No Damage” statistics include floor-frames which may have ‘ been only minimally inspected - perhaps only one or two connections cleaned. With more complete inspection, some damage may be found. (Of the 661 undamaged floor-fkames, 471 had at least half of their connections visually inspected or at least a quarter of them UT’d.) Second, the number of buildings in these two categories indicates the number in which ut least onejloor-j?wrnehad no damage or only weld damage. However, the number of buildings with no damage or only weld damage in the entire building can be derived fkom the table: No. No. No. No. No. 51 of buildings surveyed: 44 (86%) with any damage: 51-44 = 7 (14%) with no damage at all: 32 (63%) with more than weld darnage: 44-32 = 12 (24%) with weld darnage only: On a floor-frame basis, the corresponding totals are taken directly from Table 4-2: No. No. No. No. No. of floor-frames surveyed: with any damage: with no damage: with more than weld damage: with weld damage only: 1290 629 661 186 426 (49%) (51%) (14%) (33%) Discounting minor weld damage, the percentage of buildings with serious damage can be estimated as 63% with more than weld damage plus half (1-WDR using survey-wide average WDR of 0.50) of the 24 % with weld damage only, or a total of 75 %. Similarly, the percentage of floor frames with no serious damage can be estimated by taking 51% with no damage plus half of the 33 % with weld damage only, or 67%. Thus, while most buildings (75%) had serious damage to welds or parent metal, most individual flcwr-frames (67%) did not. Another way of stating this is that only 33.% (100%-67%) of floor frames had serious damage. And, because a damaged floor-frame can have several undamaged connections, it stands to reason that fewer that 33% of individual connections would have serious damage. (A database of individual connections, as opposed to floor-frames, would establish this percentage more reliably.) This limited data suggests that damage estimates and reliability analyses can assume a worm cuse loss of about 33% of all MRF connections. In other words, an owner or engineer assessing a typical but as yet uninspected MRF in West L.A. (for example) can reasonably assume that no more than 30% of the building’s connections are damaged and can plan inspections or changes in building use accordingly. Of course, this percentage must be tempered by the influences of various site and design factors discussed below. Furthermore, a reliability analysis must consider the likelihood that within a single floor-flame the loss of one connection may trigger damage in its neighbors, leading to the functional loss of the entire floor-free. Such a study is beyond the scope of this survey. 4-1o 4.2.3 No Damage Table 4-3 isolates the seven buildings with no damage at all. Only four zones are represented, but they are the zones furthest from the epicenter and with the largest numl.wr of surveyed buildings. It is noteworthy that every zone with more than four surveyed buildings has at least one building with no damage. Recalling that the overall survey sample (as of October, 1994) probably represents the worst conditions within the MRF population, this suggests that broader inspection will reveal more and more buildings with limited or no damage. On the other hand, some of the buildings in Table 4-3 were only minimally kspected; although the survey data is not conclusive (see Section 5.3), it is reasonable to expect that more complete inspection could reveal more damage. MRF stones Upper Floor Area [mq LAX 1970 15 2,000 MC 5 13 13 JAM7489 so 1979 6 2,000 MCL 7 8 8 MNH04 so 1981 6 3,000 MCL 12 31 31 BJlo WH 1990 5 4,600 MCL 13 35 35 FEl WLA 1%s 17 2,100 MC 4 12 12 MNH03H WLA 1978 3 700 w 9 32 0 NYA592 WLA 1%9 20 2,300 LC 10 10 10 DM1 zone Floor Insp’d Year Desiined Building ID Flr-Fnns Tested Conm Colms Const Table 4-3. Surveyed Buildings with No Damage 4.2.4 Weld Damage Only Table 4-4 isolates the twelve buildings with weld damage only. As with the undamaged buildings, this subset represents a range of locations, ages, sizes, and materials. Again, note that each of the most-represented zones has buildings with weld damage only. Two of these buildings, BAK and ES14, have weld damage so widespread that their damage scores approach those of buildings with more serious fractures. 4.2.5 Column Web Damage Table 4-5 isolates the 12 buildings with the most serious damage fracture through the column flange into the column web. (Buildings LCIB and LCIE also have column web (CW) damage but are not included here because of incompatible survey data.) Only the two zones furthest from Northridge, eaeh of which has only one surveyed building, are not represented. The range of building ages and heights appears more narrow for these buildings, all of which are post-1978, and all but one of which is less than six stories. (However, note that BJ02E is 4-11 Building II m zone SOM1 IMSV BW Damage Year MRF Upper Flr m De&d Stories Area [mq Cimt 119861 4 11,700 score A36 IW A36 1.00 9 6 0.33 --t10 1.25 BAK so 1982 6 1,900 MCL A572#50 A36 0.00 12 NYA550 so 1985 6 2,000 MCL A572-A36 A36 1.00 15 0 4 0.13 ES18 WH 1987 25 2,500 MC M72-Gr50 A36 0.80 216 74 77 0.49 NYA539 WH 1984 3 2,600 MC A36 A36 1.00 14 6 * 13 0.68 ES14 WLA 1988 27 1,300 A36 0.10 10 5 6 1.54 JAM7486 WLA 1983 13 1,500 MC 1 9 0.11 MNH03AB WLA 1978 3 1,000 w MNH03F WLA 1978 3 500 mo3G WLA 1978 3 400 MCL A572-Gr50 A572-Gr501 A36 I 1.00 I 44 I * 5 3 w 0.28 I I 0.26 m 1 1 w I 0.13 1 NYA577 WLA 1980 14 1,600 MCL NYA591 WLA 1970 28 2,200 MCL 19 I 0.53 Table 4-4. Surveyed Buildings with Weld Damage Only Building ID I zone Year MRF Des’d stories BJ06 NR EQE1 Sc EQE2 Sc ES12 SM JAM7482 so k II Flr Cnst Column steel Beam WDR FlrsteeJ Frms Cw hunage score 1989 2 4,700 MC A572-Gr50 A36 0.75 12 3 2.21 1991 4 2,000 MC A572-Gr50 A36 0.00 16 7 4.31 1991 1 2,500 MC A36 A36 0.00 5 4.17 1990 5 2,000 A36 0.00 1 1 5.00 1983 4 1,300 w A36 A36 0.50 28 1 1.39 1985 4 1,500 MCL A36 A36 0.50 20 1 2.40 $ 11------ F Upper Flr Area [my MCL A572-Gr50 ,6 JAM7484 so BJ02E Uc 1992 3 2,700 MC A572-Gr50 A36 0.50 27 5 3.30 WEA Uc * 1979 4 1,700 w A36 A36 0.00 24 5 1.54 1978 I 4 2,600 I MC I A36 1984 3 1.67 KAR2 MNH02 1= IA3610.201 1216 3.32 JAM7480 WLA 1983 11 2.81 MNH03CDE WLA * 1978 3 0.22 Table 4-5. Surveyed Buildings with Column Web Damage 4-12 Building ID zone Dir’n Flr No of Bays Typ &y Width [m] Typ Ext COI Typ Int Col Typ Beam BJ06 NR NS 2 5 9.8 W21X364 W21X364 W36X230,260 BJ06 NR NS 2 5 9.8 W21X333 W21X333 W36X230,260 BJ06 NR NS 3 5 9.8 W21X364 W21X364 W36X135, 150 LCIB NR NEsw 3 9.5 wl4x233342 W14X233-342 W21,W24, W27 LCIB NR NWSE 3 6.1 m W14X176-233 W21x62W24X117 LCIE NR NS 2 9.5 W14X233 W14X233 W21x83W24X131 EQE1 Sc NS 2 4 6.1 W14X159 W30X116 EQE1 Sc NS 2 4 6.1 W14X159 W30X116 EQE1 Sc NS 3 4 6.1 W14X145 W3OX1O8 EQE1 Sc NS 3 4 6.1 W14X145 W3OX1O8 EQE1 Sc EW 3 3 6.1 W14X211 W33X130 EQE1 Sc NS 4 4 6.1 W14X145 W27X94 EQE1 Sc NS 4 4 6.1 W14X145 W27X94 EQE2 Sc NS 1 2 7.3 W12X136 EQE2 Sc NS 1 1 8.2 W12X190 EQE2 Sc EW 1 2 7.3 W12X136 W24X76 EQE2 Sc EW 1 2 7.3 W12X136 W24X76 EQE2 Sc NS 1 2 6.1 W12X136 W30X99 ES12 SM EW 2 1 6.1 W14X193 m W36X135 JAM7482 so NS 2 2 10.2 W14X398 W14X398 W36X21O W24X76 ml Table 4-6. Surveyed Floor-Frames With Column Web Damage 4-13 W36X160 Building zone Diryn ID I’lr No of Bays Typ Typ Ext Bay CO1 Typ Int cd TypBeam Width [m] JAM7484 so NS 1 1 11.9 W14X311 m W36X230 BJ02E Uc NS 2 3 10.4 M W24X162 W24X84, W36X21O BJ02E Uc NS 2 3 10.4 m W24X192 W36X135 BJ02E Uc NS 2 3 10.4 m W24X192 W36X135 BJ02E Uc NS 3 3 10.4 na W24X279 W36X21O BJ02E Uc NS 3 3 10.4 na W24X279 W36X21O WEA Uc EW 2 1 7.3 W24X68 na W24X76 WEA Uc EW 2 1 7.3 W24X110 na W33X118 WEA Uc EW 2 1 7.3 W24X110 ml W33X118 WEA Uc EW 2 1 9.1 W27X145 na W36X160 WEA Uc EW 3 1 7.3 W24X94 na W3OX1O8 KAR2 WH NS 2 4 9.1 W14X136 W 14x342 BU42 KAR2 WH NS 2 4 9.1 W14X136 W14X370 BU42 KAR2 WH NS 3 4 9.1 W14X95 W14X211 BU42 KAR2 WH NS 3 4 9.1 W14X95 W14X211 BU42 KAR2 WH NS 4 4 9.1 JW4X84 W14X158 BU42 KAR2 WH NS 4 4 9.1 W14X84 W14X158 BU42 MNH02 WH NS 1 2 8.5 BU24 BU24 BU40 MNH02 WH NS 1 2 8.5 BU24 BU24 BU40 MNH02 WH NS 1 2 8.5 BU24 BU24 BU40 h4NHo2 WH NS 1 2 8.5 BU24 BU24 BU40 JAM7480 WLA EW 11 6 8.8 MNH03C DE WLA NEsw 2 2 3.4 W36X150 W14X90 Table 4-6. Surveyed Floor-Frames with Column Web Damage (continued) 4-14 W21X50 actually a 3-story MRF on top of a 6-story concrete structure.) Note that while buildings WEA and MNH02 have relatively many floor-frames with at least one cracked column web, their damage scores are close to the average building score of 1.15 (see Section 4.2.1). This suggests a deficiency in the scoring formula, since these buildings should be considered heavily damaged. Column web cracking is serious and rare enough to warrant more lists characteristics information Tables building of each floor-frame for each liskxl building 4-5 and 4-6, with column can be found it is clear that column web (CW) in Table web fractures fill damage. description. 4-5 and in Appendix have occurred Table Additional A. in a variety From of locations, sizes, frame configurations, diaphragm types, and framing details. 4-15 4-6 “ 5.0 Correlating the Damage 5.1 Method Valid correlations between damage and building characteristics require data samples of reliable quality and comparability. The sources of survey error given in Section 3.2 must be considered in all of the discussions that follow. For this report, correlations are studied by comparing damage scores or damage ratios of a specific subset of buildings or floor-frames to the aggregate scores and ratios of a larger subset, usually the complete set of surveyed conditions. It should be emphasized that the correlations cited are not based on statistics. For the survey as a whole, aggregate scores and ratios include the following rounded values, as discussed in Sections 4.2.1 and 4.2.2: Damage Score: average for buildings with 6 or more floor-frames building average plus one standard deviation floor-frame aggregate Damage Ratios: bottom weld top weld bottom column flange 1.15 2.29 0.98 .41 .16 .12 (Note that none of the correlations include data from buildings LCIB and LCIE, whose survey responses were not comparable to those of other buildings.) 5.2 Non-MRI? Damage Except in the most severe cases, MRF connection damage is impossible to identify without disruptive and costly inspection. It would be useful to know if the extent of MRF darnage could be predicted on the basis of visible non-MRF damage. The survey forms recorded nonMRF damage only in qualitative, narrative form, as shown in the Appendix A summaries. Most of the surveyed buildings reported some non-MRF structural damage, ranging from minor spalling around base plates to permanent lateral set and, in one case, near partial collapse. Eight buildings were found to have significant permanent lateral set, as summarized in Table 5-1. (Note that most surveyed buildings were not checked for plumbness. Also, note that buildings can experience substantial inelasticity without measurable lateral set.) The average damage score for these eight buildings is 2.2, significantly higher than the survey average. 5-1 kilding m zone stones Damage score BAK so 6 1.25 Non-MRF Structural Damage YES - Out of plumb64 to 76 mm(2.5 to 3 in) in the N-S direction. BJ05 NR 11 1.10 YES- Northerly51 mm (2 in) permanent displa~ment @ roof (1 lth floor). EQE1 Sc 4 4.31 YES -51 mm (2 in) perm. deflection to S at ruof, 3.49 cm (1.375 in) at ground floor. 35 mm (1.375 in) perm. deflection to W at roof, 25 mm (1 in) at ground floor. EQE2 Sc 1 4.17 YES -102 mm (4 in) perm. deflection to NW at roof. Crack across diaphragm with 51 mm (2 in) separation. Pullout failure of pm-cast attachments. Failure of non-moment beam connection at drop of roof about 102 mm (4 in). Pullout of roof from block walls. Pounding damage of block walls with roof diaphragm and with adjacent parking structure. JAM7484 so 4 2.40 YES - Distortion to beam web & shear tab in a few nonfram umnections. 51-89 mm (2-3.5 in) out-of plumb, northerly, at 4th floor. KAR3 so 17 2.00 YES - Measured deflection of 89 mm (3.5 in) of the top relative to the base of 18-story N-S frame. All the deformation is within the top six stories. SOA so 4 1.95 YES - Base plate anchors broke free from base plates. Large areas of spalled concrete around many cQlumn bases. One base shifted 19 mm (.75 in) north, another 10 mm (.375 in). WJE1 WH 18 0.46 YES -152 mm (6 in) perm. lateral displacement in height of 18 story building. Steel stair connections broken. Mechanical room block walls broken at comections to steel floor framing. Marble panel anchorages in lobby damaged. Table 5-1. Surveyed Buildings with Reported Lateral Set Table 5-2 shows the aggregate damage for the 202 inspected floor-frames in these eight buildings. Only the number of floor-frames with bottom column flange (BC) damage is significantly higher than average. The column web (CW) damage ratio of 0.06 represents 13 floor-frames, but twelve of these are in only two buildings. In summary, permanent Mend set appears to be only weakly related to significant MRF connection damage. In fact, building BAK sustained a permanent lateral set with weld damage only. Current survey responses do not justify a correlation study between MRF connection darnage and non-structural damage. First, nonstructural damage is expected in large earthquakes. Second, although most surveyed buildings had some non-structural damage, the reported damage is highly varied, and much damage had .aIready been repaired by the time MRF connection inspection began. Finally, there is strong anecdotal evidence that MRF damage can be present either with or without heavy non-structural damage [SEAOC Seismology Committee, 1994]. 5-2 No of Bhi@ 8 WDR 0.24 Flr-Frms 202 Damage Score Damage Class BC TW BW s Cw 0.28 0.09 0.41 0.09 0.06 1.56 / 4 Table 5-2. Aggregate Damage Ratios and Score for Surveyed Buildings with Reported Lateral Set 5.3 Scope of Inspection Even assuming reliable and consistent UT, a limited inspection program may fail to find widely scattered damage. A sufficient inspection scope is essential if damaged MRF’s cannot be identified by outwardly visible damage (see above) or by geographic location (discussed below). With current survey data, a study of observed damage vs. scope of inspection can consider the number of inspected floor-frames within a building and the number of inspected connections within a floor-frame. Since complete testing may have been motivated by visible connection damage, this correlation study should only include buildings in which damage could not be observed easily through fireproofing. The subset considered here consists of the 19 buildings with no damage or weld damage only. Of these 19, only one was fully inspected; that is, only building ES18 had close to 100% of its floor-frames and connections tested. Only six of these buildings had at least 25% of their total floor-frames reported and 25% of the connections in those floorframes tested. The average damage score for the 13 least-inspected buildings with no damage or weld damage only is 0.31; the average score for the other six more thoroughly tested buildings is 0.29. As this data is sparse, these averages are not especially meaningful, except to show that the survey data for this subset of buildings cannot conclusively show a link between darnage and level of inspection. A different subset of somewhat more damaged buildings is the set with column flange damage but without visible shear connection or column web damage. Ten buildings, with damage scores ranging from 0.2 to 2.5 and averaging 1.1, meet this criterion. Of these, five had testing of at least half of the connections in at least half of all floor-frames. (Note that this is a noticeably higher level of inspection than in buildings with no damage or weld damage only.) These five have an average score of 1.3, while the less inspected five averaged 0.9. Again, without robust data, the survey results are suggestive but not conclusive of a link between scope of inspection and observed damage. In some buildings, structural analysis was used to locate connections for testing. If damage locations can be determined rationally, then there could be a negative correlation between damage and testing, as marginal testing will consider fewer and fewer critically stressed locations. Survey data is insufficient to test this hypothesis on a floor-frame level. As noted in Section 3.1.2, access to the beam top flange and the outside of connections in perimeter frames was frequently limited. It is possible that the incidence of top column 5-3 flange (T.C) damage are so few because the inspection and testing there was limited, but the survey data is not complete enough to test such a hypothesis. Some engineers suspect that serious damage at the top of the connection would manifest as damage to the diaphragm above; if no evidence of diaphragm damage was seen, then limited inspection of the top flange is justified. In addition, there are reasons to believe that damage at the top of the connection shoukf be more rare than at the bottom: at the top, the extreme flange fiber is at the toe of the weld, not at the root/backing bar notch; for a beam acting compositely with a concrete slab, the imposed bending is resisted in part by the slab; and in composite members, the neutral axis is shifted from the steel mid-depth up toward the top flange, leading to higher strains at the bottom weld and lower strains at the top. Given these explanations, it is reasonable to look for top column flange (TC) darnage and top flange weld (TIN) darnage at non-composite beams. However, the eight buildings and 214 floor-frames with wood diaphragms showed no higher incidence of these darnage classes than did those with metal deck and concrete fill. 5.4 Location 5.4.1 Zone Table 4-1 gives damage data for the surveyed buildings sorted by gwgraphic zone. Each zone represents a range of damage levels, showing that buildings subjected to similar ground motions exhibited markedly different performance, even though their steel MRF structures were probably designed to similar criteria. There is not a direct correlation between geographic location and extent of MRF damage. Tables 4-3, 4-4, and 4-5 give the zones represented by three different damage levels. Table 5-3 summarizes the damage for each zone, giving the ratio of damaged floor-frames in each class and the aggregate damage score for the entire zone. By damage score, Santa Clarita (SC), Universal City (UC), and Santa Monica (SM) are significantly above the survey average of 1.0, although these zones all have small samples of only three buildings each. This supports the suggestion from Section 4.2.3 that the survey’s limited sample has captured the worst damage in each zone and that further inspection and testing witiln a given zone will reveal 5.4.2 some buildings with minor or no damage. Adjacent Buildings A study of neighboring but othenvise very different buildings requires greater detail than the current survey provides. Three sets of buildings, however, are on adjacent sites and are constructed from similar details as distinct but related parts of larger projects: BJ1O & 11, BJ05 & 06, and MNH03AB, CDE, F, G, & H. Table 4-1 is sufficient to show that the extent of darnage can vary greatly, even in these similar adjacent buildings. In particular, BJ1O is undamaged while BJl 1 has column flange tears in one fourth of its floor-frames. The 5-4 “ MNH03 buildings have similar low damage in all five buildings zone is in the irregular No of Bh@ Fk-Fnns scores, (U-shaped) but note that the only non-weld damage MNH03CDE. Damage Class WDR Damage score BC Tw BW s Cw 0.00 0.00 0.00 0.00 0.00 0.00 1 5 1 9 1.00 0.00 0.00 0.67 0.00 0.00 0.33 NR 2 67 0.71 0.27 0.06 0.66 0.03 0.04 1.30 Sc 3 26 0.09 0.81 0.00 0.12 0.31 0.46 3.78 SM 3 70 0.49 0.23 0.64 0.93 0.03 0.01 2.14 so 11 189 0.50 0.12 0.13 0.44 0.06 0.01 o.% Uc 3 52 0.28 0.42 0.25 0.58 0.10 0.19 2.63 10 495 0.66 0.07 0.18 0.38 0.02 0.02 0.72 15 365 0.27 0.07 0.07 0.29 0.01 0.01 0.61 Table 5-3. Damage Ratios and Scores by Zone Direction No of Bhlgs Flr-Fnns WDR Damage Class BC TW BW s Cw Damage score EW 37 449 0.54 0.11 0.14 0.36 0.02 0.02 0.80 NEsw 10 156 0.34 0.08 0.19 0.37 0.01 0.01 0.87 NS 38 481 0.53 0.20 0.15 0.52 0.06 0.06 1.35 NWSE 10 192 0.44 0.02 0.19 0.30 0.00 0.00 0.55 Table 5-4. Damage Ratios and Scores by Frame Direction 5.4.3 Dwectionality Table 5-4 separates the reported floor-fkames by compass direction, clearly showing greater damage in North-South frames. Table 5-5 breaks the data down further by geographic zone, ignoring zones LAX and MW which have only one building each. (Note that at thk level, a number of zone-direction combinations are represented by only one or two buildings and relatively few floor-frames.) Data from zones SO, WH, and WLA show that the N-S 5-5 . directionality is strongest north of tie Santa Monica Mountains and weakest in Santa Monica and West L~A. It should be noted that strong motion records in the Santa Monica area showed a stronger E-W component than N-S component. zone Dkection No of WDR Damage Class Flr-Fnns Bldgs BC Tw BW s Cw Damage score NR EW 2 0.71 30 0.,20 0.07 0.70 0.00 0.00 1.00 NR NS 2 0.71 37 0.32 0.05 0.62 0.05 0.08 1.54 Sc EW 3 0.09 13 0.77 0.00 0.08 0.31 0.23 2.95 Sc NS 3 0.09 13 0.85 0.00 0.15 0.31 0.69 4.60 SM EW 1 0.00 1 1.00 0.00 0.00 0.00 1.00 5.00 SM NEsw 2 0.42 30 0.40 0.77 1.00 0.07 0.00 2.84 SM NWSE 2 0.56 39 0.08 0.56 0.90 0.00 0.00 1.53 so EW 9 0.61 84 0.05 0.13 0.36 0.00 0.00 0.53 so NS 11 0.41 105 0.17 0.13 0.50 0.11 0.02 1.33 Uc EW 2 0.21 28 0.25 0.14 0.50 0.04 0.14 1.83 Uc NS 3 0.35 24 0.63 0.38 0.67 0.17 0.25 3.53 WH EW 10 0.63 204 0.05 0.19 0.29 0.01 0.00 0.54 NESW 1 0.80 24 0.00 0.17 0.2s 0.00 O.Oil 0.29 NS 10 0.64 219 0.12 0.17 0.52 0.03 0.05 1.02 NWSE 1 0.80 48 0.00 0.21 0.2s 0.00 0.00 0.32 WLA EW 8 0.33 82 0.13 0.12 0.44 0.01 0.01 0.98 WLA NEsw 7 0.21 102 0.01 0.03 0.22 0.00 0.01 0.37 WLA NS 7 0.37 76 0.16 0.09 0.49 0.04 0.00 1.05 NWSE 7 0.22 105 0.00 0.05 0.10 0.00 0.00 0.18 Table 5-5. Damage Ratios and Scores by Zone and Frame Dmtion N-S directionality in the five northernmost zones is corroborated by reports of permanent lateral set, given in Table 5-1, and by the darnage data in Tables 5-6 and 5-7. In 3-bay frames with bay widths of 9.1 to 12.2 meters (30 to 40 feet), there are 100 surveyed fioorframes overall. As can be determined from Tables 5-6 and 5-7, all of the shear (S) and column web (CW) damage and 14 of 16 bottom column flange (IX) damage cases are in the N-S direction. 5-6 TypMY No of Bk@ Flr-Fnns Damage Damage Class WDR ! Width [m] BC TW BW s Cw 4.6-5.8 9 114 0.29 0.09 0.11 0.18 0.01 0.00 0.54 6.1-8.8 15 87 0.45 0.14 0.13 0.43 0.05 0.01 0.98 9.1-12.2 15 100 0.82 0.16 0.09 0.38 0.03 0.05 0.85 Table 5-6. Damage Ratios and Scores for 3-Bay Frames by Bay Width Typ my W~dth [m] II ‘1‘ No of Bldgs Flr-Fnns 4.6-5.8 I -m 0.70 -i Cw I 0.00 I 0.00 I 0.06 I 0.00 6.1-8.8 II 9.1-12.2 + 1“ Damage score 0.00 0.05 0.00 0.81 0.10 1.39 Table 5-7. Damage Ratios and Scores for 3-Bay Frames by Bay Width: North-South Frames, 1 to M-Story, Zones NR, SC, SO, UC, WH 5.5 Concept Design 5.5.1 Height As shown in Table 4-5, column web (CW) damage is mostly limited to buildings shorter than six stories. Overall, the average damage score for 34 surveyed buildings less than seven stories tall is 1.2, about the same as the average for the entire survey. Damage ratios for these buildings are also close to overall survey averages: bottom weld (BW) damage, 0.44; top weld (T’W) damage, O.16; bottom column flange (BC) damage, 0.16. Damage in the 14 taller buildings (excluding )3S18, whose 216 floor-frames skew the sample) is somewhat lower than average, but not significantly so. Thus, short buildings do not appear significanffy more prone to MRF darnage than tall buildings. The location of damage within a building’s height may indicate that damage is associated with certain modes of vibration. Table 5-8 shows damage characteristics for frames at each level of 3 to 5 story buildings. (Floor #1 data may be anomalous, since ground floor ecmditions vary greatly depending on column fixity and basement structure. Roof data may also reflect various loading and penthouse framing conditions.) In 3- and 4-story buildings, Table 5-8 shows a CIW trend: more damage at lower stones, notably bottom column flange (BC) damage, bottom weld (WV) damage and column web (CW) damage. This reflects the 5-7 story drift and shear distribution of a flexible frame in its first vibration male. The trend does not show in the 5-story buildings, although the data there is relatively sparse. stories Floor # or Roof No of Bkigs FlrFires WDR 3 1 3 24 3 2 11 3 3 3 Damage Class Damage BC Tw BW s Cw 0.88 0.17 0.25 0.71 0.00 0.17 1.43 95 0.17 0.13 0.09 0.47 0.04 0.04 1.22 10 78 0.15 0.08 0.05 0.31 0.01 0.03 0.74 Roof 9 69 0.12 0.04 0.01 0.13 0.01 0.00 0.32 4 1 3 19 0.21 0.21 0.42 0.58 0.21 0.05 2.29 4 2 10 47 0.38 0.53 0.28 0.68 0.17 0.19 3.05 4 3 10 49 0.40 0.31 0.22 0.55 0.14 0.12 2.12 4 4 10 48 0.39 0.23 0.19 0.54 0.02 0.08 1.56 4 Roof 7 32 0.33 0.13 0.25 0.47 0.03 0.00 1.15 5 1 3 16 0.98 0.19 0.06 0.31 0.00 0.00 0.57 5 2 5 37 0.62 0.05 0.05 0.43 0.00 0.03 0.62 5 3 4 27 0.57 0.11 0.15 0.30 0.00 0.00 0.63 5 4 4 22 0.48 0.14 0.09 0.27 0.05 0.00 0.73 5 5 2 20 0.45 0.05 0.05 0.20 0.05 0.00 0.46 5 Roof 2 18 0.40 0.00 0.00 0.06 0.00 0.00 0.06 ‘ TabIe 5-8. Damage Ratios and Scores in 3 to 5-Story Buildings by Floor Level Table 5-9 gives data characteristics for different portions of six 11- to 14-story mid-rise buildings. Bottom weld (BW) darnage is observed at about the same rate at lower and upper levels. Greater bottom column flange (13C)damage leads to higher ratios and scores around mid-height and at top floors, but this may be an artifact of limited sample sizes. For the six surveyed mid-rise buildings, there is no clear correlation between damage and floor number. Limited data (see Table 3-3) prohibits useful studies of damage vs. floor number for highrise buildings. 5-8 StorieslFloor#l Noofl Bldgs Fir- IWDRI Fnns Damage Class BC TW BW s Cw I Damage score 11-14 2-4 5 50 0.79 0.12 0.00 0.46 0.1 O.(XI 0.73 11-14 5-7 6 63 0.75 0.22 0.06 0.51 0.1 O.w 1.00 11-14 8-10 5 57 0.80 0.07 0.04 0.53 0.0 0.00 0.57 11-14 11-15 6 40 0.70 0.20 0.05 0.48 0.0 0.03 0.95 Table 5-9. Damage Ratios and Scores in 11 to 14-Story Buildings by Floor Level 5.5.2 Frame Conjuration With reference to Table 3-6, Tables 5-10 and 5-11 give damage characteristics according to the number of bays per frame. Both tables exclude frames of more than five bays, which are not as well represented. Table 5-10 considers all surveyed buildings (except LCIF3and LCIE). Note that the 2-bay frame data is dominated by 216 floor-frames from building ES18. As a group, l-bay frames have the highest damage score and bottom weld @w) and top weld (TW) damage ratios, but they do not stand out from the other groups as significantly more prone to damage. Survey wide, there does not appear to be a correlation between observed damage and the number of bays per frame. ‘yslNOOfB’@slmr-F-lmR Damage Class Damage score BC 13 I 205I 0“330.11 0.24 0.53 0.04 0.04 1.32 21 18 I 3 1 I 448 I 0.50 0.08 0.23 0.38 0.00 0.02 0.84 29 301 0.50 0.13 0.11 0.32 0.03 0.02 0.79 4 20 135 0.56 0019 0.08 0.47 0.05 0.09 127 .. 5 12 124 0.53 0.18 I 0.02 I 0.39 I 0.14 I 0.02 I 1.10 Table 5-10. Damage Ratios and Scores by Number of Bays per Frame Table 5-11 considers the same data for a subset of floor-frames: North-South (NS) oriented frames in low- and mid-rise buildings (1 to 14 stories), located north of West L.A. in zones that showed predominant NS directionality (see Table 5-3). As NS frames have already been shown to have more damage in these zones, the high scores and ratios in Table 5-11 are not surprising. One- and 2-bay frames have the highest weld damage ratios, but 4- and 5-bay 5-9 frames have very high ratios of column flange cracking and the highest damage scores overall. In light of obsenmi Northridge damage, the use of l-bay frames has been questioned because each connection represents half of a frame’s energy dissipation capacity, and with only two connections per floor, the loss of one could greatly increase demand on the other. Although the data is limited for this narrow subset of floor-frames, Table 5-11 shows that l-bay frames experienced only average damage. Despite this finding, one bay frames continue to present a concern for Engineers due to their lack of redundancy. Because 4- and 5-bay frames are highly redundant, the severity of high scores shown in Table 5-11 depends on the number of damaged connections within each frame, but those numbers were not tracked by the survey. Bays No of Bldgs II FIr-Fnns Damage Ssore Damage C1aM WDR BC lTw IBw ISICw 1 7 44 0.41 0.07 0.25 0.55 0.14 0.07 1.48 2 7 37 0.56 0.30 0.14 0.70 0.00 0.19 1.95 3 11 98 0.71 0.16 0.12 0.43 0.03 0.05 0.97 4 7 40 0.55 0.43 0.03 0.43 0.10 0.30 2.38 5 4 0.37 0.36 0.04 I 50 I 2.14 Table S-11. Damage Ratios and Scores by Number of Bays per Frame: North-South Frames, 1 to 14-Story, zones NR, SC, SO, UC, WH Tables 5-6 and 5-7 show the damage in the most common frame configuration, 3 bays, broken down by typicaI bay width. Table 5-6 considers all surveyed floor-frames; Table 5-7 considers only NS floor-frames in 1-14 story buildings north of West L.A. Surprisingly, the subset of North-South data shows less overall damage than the survey as a whole. Both tables show somewhat less damage in frames with shorter bays, though the Table 5-7 data is sparse. At best, there is a weak correlation between damage and long bays. 5.5.3 Redundancy As described in Section 3.3.2, Table 3-7 lists the least re$undant frames in the survey: those with only one or two bays in directions with only two frames. For the seven buildings represented, &mage scores range from 0.46 to 2.51, averaging 1.55, somewhat greater than the overall survey average. Table 5-12 gives the aggregate damage for these least redundant floor-frames. All the damage ratios and scores are close to the survey-wide averages. By this measure, at least, there is no correlation between observed damage and Iack of structural redundancy. Surveyed buildings that are least redundant and irregular are discussed in the next section. 5-1o No of Bldgs Flr-Fnns WDR 7 128 0.16 Damage Class BC Tw BW s Cw 0.13 0.22 0.44 0.03 0.02 Damage score 1.2s i Table 5-12. Aggregate Damage Ratios and Scores for Least Redundant Buildings (Ref. Table 3=7) 5.5.4 Irregularity Table 3-8 lists potential irregularities in surveyed buildings. The 27 buildings listed represent both the lowest and highest damage scores in the survey. Their average score is 1.2, the same as the survey average. The average damage score for the eight buildings with both plan and vertical irregularities is 1.1. Note that the scope and severity of listed irregularities varies from building to building and that some or all of a building’s irregularities may have been adequately addressed during design. Table 5-13 gives aggregate damage characteristics by type of irregularity. While buildings with both vertical and plan irregularities have slightly higher bottom weld (BIN) damage ratios, the 22 surveyed buildings with no irregularities have the highest column web (CW) damage ratio and the highest damage score. Clearly, there is no correlation between damage and structural irregularity. Irregularity ass No of Bk@ Damage score S[cw ~ -+=-l+- 290 0.54 0.14 0.14 0.51 0.01 I 0.00 0.94 429 0.3s 0.19 0.14 0.39 0.07 0.04 1.25 + 0.02 0.02 0.87 0.01 I 0.02 0.86 Plan I 22 740 0.55 0.10 0.19 0.42 Vertical I 13 399 0.58 0.12 0.12 0.49 Table 5-13. Damage Ratios and Scores by Building Irregularity (Ref. Table 3-8) Of the seven ES15, BJ04, aggregate bottom least redundant and WEA. bottom column well above weld flange structures Although (BW) discussed above, hardly a robust damage (13C) damage ratio of 0.74, ratio of 0.20, sample, three also have some irregularity: these three buildings a top weld (TW’) and an average damage damage have an ratio of 0.43, score a of 1.8, all survey-wide averages. An interesting comparison is provided by the five MNH03 buildings, all fairly redundant and all built from identicd details on a shared foundation. Though only visually inspected, four 5-11 of the five experienced no damage or just weld darnage. With a C-shaped plan, Building MNH03CDE is the only irregular building of the five and also the only one with observed bottom column flange (BC) damage and column web (CW) damage. 5.6 Detail Design 5.6.1 Ykld Strength With reference to Table 3-10, Table 5-14 presents darnage characteristics for the two main column steel grades. Based on nominal strengths, there is no clear correlation between observed damage and column material strength. With survey data on nominal strengths only, however, it is difficult to draw any conclusions regarding observed darnage and material properties, since the variation of actual yield strength in A36 and multi-certified steel is well documented ~amburger and Frank, 1994]. column steel No of Bk@ A36 26 528 A572-Gr50 19 705 Table 5-14. 5.6.2 Flr-Frms Damage Class WDR Damage score BC Tw BW s Cw 0.36 0.12 0.09 0.35 0.0 0.04 0.96 0.58 0.11 0.21 0.44 0.0 0.02 0.94 Damage Ratios and Scores by Nominal Cohmm Strength Member Size Without original criteria and calculations, it is difficult to tell wh~ch issues controlled the member design for surveyed buildings. However, with bay widths of 7.6 meters (25 feet) or greater (Table 3-6) and only a handful of bays in each direction (,Tables 3-5 and 3-6), it is possible that many of the surveyed buildings, even those only three or four stories tall, were controlled by stiffness concerns, their members selected mainly to meet maximum code drift limits. For a given story drift, frame geometry, and constant relative member stiffness, beam curvatures at the column face are known, and for a given curvature, deeper wide”flange beams experience greater strains in their flanges and flange welds. These large strains may be related to observed MRF connection damage. To test this hypothesis, the following subset of floor-frames is considered: buildings 3 stories or taller with concrete diaphragms, floor-frames with typical bay widths between 7.3 and 11.0 meters (24 and 36 feet), Group 4 W14 columns (see Table 3-11), and wide flange beams of different nominal depths (see Tables 3-12 and 3-13). Table 5-16 shows the damage in these floor-frames. No consistent pattern is apparent, although the data is sparse for W30 and smaller beams. 5-12 “ In Table 5-15, the bay widths (beam spans) are limited because for similar story drifts, longer spans yield lower beam flange stresses. This fact can also be used to test the relation between damage and beam flange strain. Tables 5-6 and 5-7 show overall damage pmtems by bay width. Confining the study to floor-frees with W36 beams meeting the conditions of Table 5-15 yields the damage data in Table 5-16. Again, there is no recognizable pattern reIating damage to beam span in this subset of floor-frames. Without at least a simplified analysis, survey data are not sufficient to relate damage to design details. And without much more robust data, it may require time-history analysis with recorded ground motions to reveal any valid correlations. Typ Girder No of Bh@ Flr-Fnns WDR Damage Class I Damage score BC TW BW s Cw 0.00 0.00 0.00 0.00 0.00 0.00 W24 11 21 W27 13 3 0.65 0.00 0.00 0.33 0.00 0.00 0.28 W30 I 18 0.50 0.00 0.00 0.67 0.00 0.00 0.67 47 0.63 0.02 0.00 0.17 0.00 0.00 0.19 176 0.72 0.06 0.10 0.44 0.01 0.01 0.56 4 + + Table 5-15. Damage Ratios and Scores by WF Gwder Depth: Buildings >3 Stories, Concrete Diaphragms, Group 4 W14 Columns, and 7.3-to 11.()-m Bay Widths TypBay [m] No of B]d& DamageClass Ftr-Frms WDR BC Tw BW s Cw Damage score 4.6-6.1 7 103 0.75 0.07 0.34 0.34 0.02 0.00 0.68 6.1-7.6 6 116 0.75 0.03 0.27 0.41 0.03 0.00 0.63 7.6-9.1 10 78 0.76 0.00 0.00 0.01 0.00 0.00 0.01 9.1-10.7 12 88 0,65 0.00 0.00 0.01 0.00 0.00 0.01 10.7-12.2 2 19 0.26 0.11 0.37 0.58 0.26 0.05 2.07 12.2-15.2 3 20 0.29 0.20 0.40 0.50 0.05 0.00 1.59 Table 5-16. Damage Ratios and Scores for W36 Girders by Bay Width: Buildings >3 Stories, Concrete Diaphragms, Group 4 W14 Columns 5-13 5.6.3 Other The current survey data cannot support meaningful studies of damage eorrelat.ions by shear connection type, weld process, or composite beam behavior. Data shown in Section 3.3.3 indicates that damage to floor-frames in buildings with wood diaphragms was not significantly different from darnage patterns overall; the aggregate damage wore for the 214 floor-frames is 0.58, slightly lower than average. As noted above, buildings with similar details ean have various levels of damage, even when situated on adjacent sites. 5.7 Material & Construdion Quality The lack of measurable correlation in this set of data between observed damage and basic design characteristics suggests that correlations be sought in either demand-based or reliability-based parameters. Predictability of damage may be a function of either bed rotations and strains or a function of material and construction quality. These eases are not related to the set of concerns typically addressed by practicing engineers and the design criteria of building codes. This alone is a valuable conclusion. Still, it requires confirmation with studies beyond the scope of the current survey. Among the possible demand-based darnage indicators are: ● e e e o ● plastic rotation demand at the connection weld stress due to beam overstrength weld strain strain rate panel zone deformation causing local kinks at the flange welds through-thickness stresses in the column flange Among the possible reliability-based damage indicators are: e base metal quality e weld metal quality weld quality and workmanship, including preheat, deposition rate, interpass temperature, wind shielding, etc. inspection and testing quality, including rejection of end dams, UT reliability, etc. fabrication and fit-up, including size and shape of weld access holes, flange preparation, and root opening e e o 5-14 6.0 Conclusions and Recommendations 6.1 Conclusions Current survey data comprises 1290 inspected floor-frames from 51 steel MRF buildings. The floor-frames represent a variety of locations, building sizes, frame configurations, and construction types. The principaI conclusions drawn from this data are: ● Observed damage ranges from none to complete column web fracture. The most common damage found is partial or complete fracture of beam flange groove welds. About 40% of all reported floor-flames have some cracking in the bottom weld; about 15% have some cracking in the top weld. Three quarters of the floor-flames with top weld damage also have bottom weld damage. Overall, about half of all the reported weld damage is limited to UT-rejectable discontinuities or incipient root cracking, some of which certainly predates the Northridge earthquake. ● Damage to base metal occurs most frequently as fracture of the column flange adjacent to the beam bottom flange weld: about 15% of fkmr-frames have one or more incidence of this type of fracture. Similar damage at the top of the connection was reported in only 9 floor-frames, but the low number may be partly due to obstruction of inspection by floor diaphragms above. ● The most serious damage types, column web cracking and shear connection damage, each occurred in about 4% of reported flcmr frames, and always in combination with weld or column flange fracture. Column web fracture was observed in a variety of building locations, sizes, flame configurations, diaphragm types, and framing details. ● On a floor-frame basis, about haIf of all floor-frames reported no damage, and another third reported weld damage only. Considering that about half of all reported weld damage was “incipient root cracking” only, it can be concluded that about two thirds of all reported floor-frames had nothing more than root cracks. However, while root cracks and weld discontinuities may be relatively easy to repair or even acceptable, observed column flange and weld fracture patterns suggest strongly that serious damage is related to the condition at the weld root. Survey data was studied for correlations between observed damage and basic structural characteristics. Only two clear patterns were found. Specifically, studies of correlations between observed damage and surveyed building characteristics found thati of the Santa Monica Mountains, North-South oriented frames were more damaged than others. No strong directionality was found in Santa Monica, West Los Angeles, or Universal City. North In low-rise buildings (3 to 5 stories), lower floor levels were more damaged than upper floor levels. No similar patterns were apparent for mid-rise or high-rise buildings. 6-1 e Structural and/or or non-structural damage non-MRF damage did not cmrelate with damage ratios scores. e Building height and floor diaphragm area did not correlate with damage ratios and/or damage scores. e Frame configuration (bay length and number of bays per tie) damage ratios and/or darnage scores. e Structural redundancy (number of frames and bays in a given direction) did not correlate with damage ratios and/or damage scores. @ Structural regularity (principally building line setbacks and reentrant comers) did not correlate with damage ratios and/or damage scores. ● Member size and nominal yield strength did not correlate with damage ratios and/or damage scores. did not comelate with 6.2 Considerations In drawing these conclusions, it is essential to remember that: e The database sample is limited and perhaps unrepresentative (though probably conservatively so). The most serious damage types were reported in each of the geographic zones represented by more than one building. In the three zones with more than four surveyed buildings, buildings with no darnage at all or weld damage only were also reported. This suggests that the survey may have captured the worst damage in each zone and that inspection of more buildings will find a greater percentage with little or no damage. e The scope of inspection within each building varied, and in some cases was extremely limited. More inspection will obviously give a more accurate picture, but there is no strong evidence that more inspection wi~in a building will find more or less damage. e No estimates of true structural demands from tie Northridge earthquake were available for correlation with observed damage. * No estimates of the impact of observed damage on building performance were available, and none are implied by this report. 6.3 Implications The conclusions listed previously - especially the lack of correlation between darnage and structural characteristics - yield some lessons for engineers, researchers, and others studying 6-2 the effects of major earthquakes on steel frame buildings: ● Design standards for new construction should consider the likelihood and potential impact of brittle connection failure in the conventional welded-flange MRF connection. In response to observed Northridge earthquake damage the ICBO, in an emergency Code change, has deleted the prescribed comection fkom the 1994 UBC [“ICBO Board...,” 1994]. ● Studies of the limited survey data suggest that damage is not related to building and frame configuration, or structural detailing. Engineers and researchers studying the cause of damage and potential repair or upgrade schemes should therefore consider that MRF performance maybe a fimction of issues not typically considered by practicing designers. That is, performance may be related to peculiar ground motions (including verticxd accelerations), unique localized demands, or the reliability of material and construction quality. ● Pre-earthquake evaluation of existing steel MRF buildings should consider the likelihood and potential impact of brittle connection failure. Survey data show that approaches limited to document review and simplified analysis (e.g. FEMA 178 ~EMA, 1992]) will not account for observed behavior. ● Post-earthquake evaluation should include visual inspection and testing of some portion of MRF connections. Survey data show that assessments based on building walkthroughs (e.g. ATC-20 Rapid Evaluation Method [ATC]) may not find significant MRF damage, and that follow-up evaluations limited to visual inspection and drawing review (e.g. ATC-20 Detailed Evaluation Method [ATC]) may not uncover partkdly fractured welds and frame members. 6.4 Recommendations The value of current survey data can be enhanced by correlating observed damage with specific estimates of local ground motion and resulting frame forces, and by experimental studies to determine the effects of weld discontinuities, root cracks, and other damage patterns on connection and frame performance. Recommended future efforts directly relattxi to this survey include: ● Continued collection of data with the current scope and format. ● Continued use and improvement of the survey form developed in this effort both as a tool for data colltxtion and as an indicator of usefid information types and formats. ● Collection of recorded ground motion parameters for txich zone or neighborhood. ● Analysis of specific or generic buildings to generate demands for damage correlation studies. Both elastic and inelastic analysis, using code lateral forces and recorded 6-3 ground motions, should be used to assess the efficacy of simplified methods. e Maintenance designers, of the existing researchers, database and building and coordination with potential users, including officials. e Collection of more detailed data, especially regarding actual steel strength and weld properties. e Development of a separate database for individual connections, as opposed to floorframes. 6-4 7.0 References American Institute of Steel Construction (AISC). Manual of Steel Construction,Allowable Stress Design. Ninth Edition, AISC, Inc., Chicago, IL, October, 1989. American Institute of Steel Construction Northridge Steel Update1. AISC, Inc., (AISC). Chicago, IL, October, 1994. American Welding Society (AWS) (1986). Structural Welding Code - Steel, Tenth Edition (ANSI/AWS D1. 1-86). American Welding Society, Inc., 1986 (reprinted May 1987). Applied Technology Council (ATC). Proceduresfor Posteafihquake Safety Evaluation of Buiiiiings (ATC-20). Applied Technology Council, Redwood City, CA. (Prepared for ATC by R. P. Gallagher Associates, Inc., San Francisco.) Benson, Bill. Personal communication to David Bonowitz j NYA, September, 1994. Vitelmo V., Anderson, James C., and Krawinkler, Helmut (1994). Perjiormanceof Steel Building Structures During the Northridge Earthquake (UCBIEERC-94109). Bertero, Earthquake Engineering Research Center, Richmond, CA, August 1994. V. V., Popov, E. P., and Krawinkler, H. (1972). “Beam-Column Subassemblages Under Repeated Loading. ” J. of the Structural Division, ASCE, v98 nST5, May, 1972. Bertero, California Strong Motion Instrumentation Program (CSMIP). 5th CSMIP Quick Repo?t of January 25, 1994. Figure 1, cited in Shipp et al (1994). Engelhardt, M. D. (1994). ‘Testing of Full Scale Steel Moment Connections, Progress Report, August 2, 1994. ” Unpublished. Engelhardt, M. D. and Husain, A. S. (1993). “Cyclic-Loading Performance of Welded Flange - Bolted Web Connections. wJ. of Structural Engineering, VI 19, n12, December 1993. Federal Emergency Management Agency (FEMA) (1992). NEHRP Handbookfor the Seismic Evaluation of &isting Buildings (FEMA-178). BSSC, Washington, D. C., 1992. Freeman, Sigmund A. (1987). “Code Designed Steel Frame Performance Characteristics.” Dynamics of Structures (Proceedings of the Sessions at Structures Congress ’87 related Dynamics of Structures, Orlando, F1orida, August 17-20, 1987). American Society of Civil Engineers, 1987. Garreau, Joel. E21geCity: Lijieon the New Frontier. Doubleday, New York, 1988. 7-1 to Hamburger, Ronald O. and Frank, Karl. “Performance of Welded Steel Moment Connections: Issues Related to Materials and Mechanical Properties,” in Irzvit@”onal Workshop on Steel Seismic Issues, September 8 and 9, 1994: Strawman Papers. Holguin, Richard. Ordinance No. _. by facsimile, November 14, 1994. Personal correspondence with David Bonowitz / NYA ICBO (1988). UnijormBuilding Cbde. International Conference of Building Officials (ICBO), Whittier, CA, 1988. ICBO (1991). Un~onn Budding Gale. International Conference of Building Officials (IC130), Whittier, CA, 1991. ‘ICBO Board Approves Emergency Structural Design Provision. wBuiZdingStandards, September-October 1994, p26. Malley, Jim and Saunders, Mark (1994). “Steel Moment Frame Update. wStructural Engineen Association of Northern CalijiomiaNews, vXLIX n8, August 1994. Naeim, Farzad, ed. The Seismic Design Handbook (Chapter 5: Architectural Considerations, by Christopher Arnold). Van Nostrand Reinhold, New York, 1989. Nabih Youssef & Associates (NYA) (1994). “A Survey of Steel Moment-Resisting Frame Buildings Darnaged by the 1994 Northridge Earthquake (Preliminary Report). ” NIST GCR 94-660. Unpublished. Popov, E. P., Amin N. R., Louie, J. C., and Stephen, R. M. (1985). “Cyclic Behavior of Large Beam-Column Assemblies. ” Earthquake Spectra, V1 n2, February 1985. Popov, E. P. and Bertero, V. V. (1973). ‘Cyclic Loading of Steel Beams and Connections. ” J. of the Structural Division, ASCE, v99 nST6, June, 1973; Popov, E. P. and Pinkney, R. B. (1969). “Cyclic Yield Reversal in Steel Building Connections. WJ. of the Structural Division, ASCE, v95 nST3, March 1969. Popov, E. P. and Stephen, R. M. (1972). “Cyclic Loading of Full Size Steel Connections.” Bulletin No. 21, American Iron and Steel Institute (AISI), Washington, D. C., cited in Chen (1985) and in Popov and Tsai (1987), similar to Popov and Bertero (1973). Popov, E. P. and Ts.ai, K. C. (1987). “Performance of Large Steel Moment Connections Under Cyclic Loads. WSiGiOC Proceedings, 56th Annual Convention, October 1987, San Diego. 7-2 Preece, Robert F. Structural Steel in the 80’s - Materials, Fastening and Testing. The Steel Committee of California. Reproduced in Steel Moment Frame ClmrwctionAdvisory No. 2 (Internal WorkingDocurneti). SAC Joint Venture Partnership, Sacramento, October 19, 1994 Sabol, Thomas A. (1994). “Damage to Ductile Steel Frames in the Northridge Earthquake.” Distributed by the Structural Engineers Association of Southern California in conjunction with the Northridge Earthquake Seminar, March 26, 1994. SAC Joint Venture Partnership. Steel Moment Frame Connation Advisory No. 1. SAC, September 26, 1994. SAC Joint Venture Partnership. Steel Moment Frame ClmnectionAdviso~ No. 2. SAC, October 19, 1994. SAC Joint Venture Partnership. Steel Moment Frame ConnectionAdvi.roryNo. 3. SAC, In Progress. SAC Joint Venture Partnership. Program to Reduce EiwthquakeHazards in Steel Moment Frame Structures (Attachment A). Submitted to the California Office of Emergency Services, July 7, 1994. SAC Joint Venture Partnership. Session Summaries. Reports from Working Groups from the Invitational Workshop on Steel Seismic Issues, September 8 &9, 1994. SEAOC (1990). RecommendedLzteral Force Requirements and Commentary. Structural Engineers Association of California (SEAOC), Sacramento, 1990. SEAOC Seismology Committee (1994). “Ductile Steel Frame Beam-Column Joints: A Discussion of Preliminary Observations, Conclusions and Recommendations.” Unpublished. DRAFT copy, August 26, 1994. Shipp, John G., Sabol, Thomas A., and Lew, Marshall (1994). “Northridge Earthquake, 17 January, 1994: Seismic Performance of Steel.” Presented at the American Iron and Stil Institute 1994 General Meeting, May 18-19, 1994. Unpublished. Skiles, J. L. and Campbell, H. H. (1994). “Why Steel Fractured in the Northridge Earthquake.” Steel Moment Frame ConnectionAdvisory No. 1. SAC Joint Venture Partnership, Sacramento, September 26, 1994. Yanev, Peter I., Gillengerten, John D., and Hamburger, Ronald O. (1991) The Per$orrnance of Steel Buildings in Past Earthquakes. American Iron and Steel Institute, 1991. 7-3 . Appendix A: Survey Summaries A-l NIST Survey of Steel MRF Buildings Affected by the Northridge Earthquake Friday, January 13, 1995 Survey Form: Survey Date: 10/12/94 new Pre Nridge Status: OC Status as of 10/12/94 Inspection/Testing: Repair/Retrofit Building ID OC 1P NS ACI Geographic Zone: WIA Northridge Tag: N Non-MRF Structural Damage? NO “None so far. Pin-based columns not yet inspected.” Non-Structural Damage? Ltie Safety related: YES “Brick veneer deformed out-of-plane relative to original position.” Othec Design Code: LABC Year Designed: 1984 1984 Year Built: MRF Stories Above Ground: 3 MRF Stories Below Ground: O Ground FJoorArea [sfj: 18,000 Upper Floor Area [sfJ 18,000 Plan Irregularities? Y possible reent comers Vertical Irregularities? Y possible geom irreg at setbacks. Column Fy [ksi]:36 Girder Fy [ksi]: 36 Floor Construction Type: MC/L? Web Connection Type: B Flange Weld Process: SMAW? Number of Frames in Each Direction: N-S 4 NE-SW E-w 4 NW-SE Notes: MRF Connection Inspectionflesting Total No of Corms in Inspected FF’s: No of Connections Inspected: No of Connections Tested: Scope and Damage Summaq No of Inspected Flmr-Frames 128 %Wl : 0.0% 31 Darnage Score :%47 31 Number of Floor-Frames in each Damage Class for each inspectecUtested Frame. A-2 119 “ Friday, Janua~ 13, 1995 Survey Form: new Pre Nridge Status: NIST Survey of Steel MRF Buildings Affected by the Northridge Earthquake Survey Date: 10/11/94 OC Status as of 10/11/94 lnspectionKesting: Repair/Retrofit Building ID: OC C c BAK Geographic Zone: SO Northridge Tag: Y Non-MRF Structural Dama e? YES “out of plumb 2.5 to % inches in the north-south direction.” Non-Structural Damage? Life Safety related: K&’;~chors for exterior precast panels ‘badly deformed.’ Cracking of Ist story masonry Othec Design Code: UBC Year Designed: 1982 Year Built: 1979? MRF Stones Above Ground:6 MRF Stones Below Ground: 1 Ground Floor Area [sfl: 26,000 Upper Floor Area [sfj: 20,000 Pla~ Irregularities? Ve~cal Irregularities? Column Fy [ksi]:50 Girder Fy [ksi]: 36 Floor Construtilon Type: MCL Web Connection Type: B Flange Weld Process: U Number of Frames in Each Direction: N-S 2 NE-SW E-W 3 NW-SE Notes: MRF Connection Inspection/Testing Total No of Corms in Inspected FF’s: No of Connections Inspected: No of Connections Tested: Scope and Damage Summary 72 72 o No of Inspected Floor-Frames: 12 Yowl :0.0 YO Damage Score :1.2S Number of Floor-Frames in each Damage Class for each inspectedltested Frame. 3 A-3 NIST Survey of Steel MRF Buildings Affected by the Northridge Earthquake Friday, January 13, 1995 Survey Date: 8/31/94 Survey Form: old Pre Nndge Status: Building ID: Oc C Status as of 8/31/94 Inspection/Testing: Repair/Retrofit OC BJOI Geographic Zone: SM Northridge Tag: N Non-MRF Structural Damage? Non-Structural Damage? Life Safety related: YES “Glass block feature wall damage. Ceilings & Partiions & Shelving.” Othec Design Code: UBC Year Designed: 1989 1990 Year Built: 1988 Ground Flmr Area [sfJ: 13,550 Upper Floor Area [sfj: 13,550 MRF Stories Above Ground:4 MRF Stories Below Ground: Plan Irregularities? N Vertical Irregularities? N Column Fy [ksi]:50 Girder Fy [ksi]: 36 Floor Construction Type: MC Web Connection Type: Flange Weld Process: Number of Frames in Each Direction: N-S NE-SW 2 E-W NW-SE 5 Notes: MRF Connection InspectionlTesting Total No of Corms in Inspected FF’s: No of Connections Inspected: No of Connections Tested: Scope and Damage Summary No of Inspected Floor-Frames: 23 ‘/owl :90.0 ‘/0 Damage Score :1.36 110 110 110 Number of Floor-Frames in each Damage Class for each inspected/tested Frame. -’T 4 3 1 1 4 0 0 : A-4 0 Friday, January 13, 1995 NIST Sutvey of Steel MRF Buildings Affected by the Northridge Earthquake Survey Form: comb Survey Date: 10/13/94 Pre Nridge Status: Status as of 8/31/94 inspection/Testing: Repair/Retrofit UC Building ID: Uc C c BJ02E Geographic Zone: UC Northridge Tag: N Non-MRF Structural Damage? YES “Minor cracks in stair and elevator enclosure. CMU walls in concrete parking structure below. Minor fillet weld cracks in misc. connections to MRF columns (non-MRF members).” Non-Structural Damage? Life Safety related: na: building under instruction Othec na: building under construction UBC Design Code: Year Designed: 1992 1994 Year Built: 1991 MRF Stories Above Ground: 3 Ground Floor Area [sfl: 29,000 Upper Floor Area [sO: 29,000 MRF Stories Below Ground: O Plafi irregularities? Vertical Irregularities? N Column Fy [ksi]: 50 Girder Fy [ksi]: 36 Floor Construction Type: MC Web Connection Type: WB Flange Weld Process: U Number of Frames in Each Direction: N-S 6 NE-SW NW-SE E-W 4 Notes: MRF Connection lnspection~esting Total No of Corms in Inspected FF’s: No of Connections Inspected: No of Connections Tested: Scope and DamageSummary No of Inspected Floor-Frames: 27 135 121 121 %wl :50.0 %0 Damage Score :3.30 Number of Floor-Frames in each Damage Class for each inspected/tested Frame. 22C 22N 22s 29C 29N 29S A NS NS NS NS NS NS Ew 3 3 : 3 3 3 : : 34 18 18 18 3 18 0 0 A-5 0 2 NIST Survey of Steel MRF Buildings Affected by the Northridge Earthquake Friday, Janua~ 13, 1995 Survey Date: 9129194 Survey Form: new Pre Nridge Status: OC Status as of 9/29/94 lnspectio~esting: Repair/Retrofit BJ04 Building ID: Oc C 1P “ Geographic Zone: SO Northridge Tag: Y Non-MRF Structural Damage? YES “At 2nd floor, bolts m non-frame beams spanning N-S were sheared, 5 locations total: Note that A307 bolts were used in error. Cracks/spans in first floor concrete near most frame mlumn base plates.” NOTE: Yellow tag was based on this and LS-related non-strut damage, not on MRF damage, which was unseen. Tag was removed after preliminary repairs. Building was not retagged after dismvery of MRF damage. Non-Structural Damage? Life Safety related: YES “Stud wall (exterior building enclosure) separated from floor @ 2nd and 3rd ftoom. NE mmer stair post (steel TS) had lost anchorage to supporting block wall.” Othen Design Code: LABC Year Designed: ~981 1981 Year Built: 1980 MRF Stories Above Ground:4 MRF Stories Below Ground: O Ground Floor Area [sfj: 10,600 Upper Floor Area [sO: 10,600 Plan Irregularities? N Vertical Irregularities? Y possible geom irreg at floor 3 frame 2 setback. Column Fy [ksi]:36 Girder Fy [ksi]: 36 Floor Construction Type: MCL Web Connection Type: B Flange Weld Process: u Number of Frames in Each Direction: N-S 2 NE-SW E-W 2 NW-SE Notes: MRF ConnectionInspection/TestingScopeand DamageSummary No of Inspected Floor-Frames: 16 TotalNo of Corms in Inspected FF’s 74 Yowl :30.0 % 73 No of Connections Inspected: Damage Score :1.25 No of Connections Tested: 73 Number of Floor-Frames in each Damage Class for each inspectedltested Frame. 2 6 BW 4 NS A-6 s Pz 0 o Cw 0 .0 04 0 Friday,Januafy 13, 1995 NIST Suwey of Steel MRF Buildings Affected by the Notthridge Earthquake Survey Form: new Pre Nridge Status: Suwey Date: 10/6/94 OC Status as of 10I6I94 Inspectionfiesting: Repair/Retrofit BJ05 Building ID: Oc JP NS Geographic Zone: NR Northridge Tag: N Non-MRF Structural Damage? YES “Northerly 2“ permanent displacement@ rmf (1lth floor).” Non-Structural Damage? Life Safety related: NO Other YES “Ceilings, furnishings, floor tiles, lobby stonework damaged.” Design Code: LABC Year Designed: 1990 1991 Year Built: 1988 MRF Stories Above Ground: 11 MRF Stories Below Ground: 1 Ground Floor Area [sfl: 29,000 Upper Floor Area [sO: 25,000 Plan Irregularities? Y out-of-plane offsets at floors 2 and 9. Vertical Irregularities? Y possible mass irreg at floor 9 setback. Column Fy [ksi]:50 Girder Fy [ksi]: 36 Floor Construction Type MC Web Connection Type: WB Flange Weld Process: SlvlAW? Number of Frames in Each Direction: N-S 4 NE-SW E-W 2 NW-SE Notes: .. r MRF ConnectionInspection/TestingScope and DamageSummary TotalNo of Corms in Inspected FF’s: 548 No of Inspected Floor-Frames: 55 %wl :70.09’0 No of Connections Inspected: 361 No of Connections Tested: 361 Damage Score :1.10 Number of Floor-Frames in each Damage Class for each inspectedtested Frame. 16 18 NS NS ; K EW !.5 1.5 L Ew 1% .- : 7 3 3 7 0 6 3 ;: li 0 o 0 0 8 ;: 32 16 : 7 A-7 : 0 0 0 0 NIST Suwey of Steel MRF Buildings Affected by the Northridge Earthquake Friday, January 13, 1995 Survey Date: 10/7/94 Survey Form: new Pre Nridge Status: Oc Status as of 10/7/94 Inspection/Testing: Repair/Retrofit Building ID: Oc 1P 1P BJ06 Geographic Zone: NR Northridge Tag: N Non-MRF Structural Dama e? YES “lnsfgnificant (1/4”) ~teral set determined by survey.” Non-Structural Damage? Life Safety related: YES “spalling at precast connections;” damagelbreakage to “floor tiles, partitions, windows, ceilings;” “furnishings fell over.” Other Design Code: IABC Year Designed: 1989 Year Built: 1991 1988 MRF Stories Above Ground: 2 MRF Stories Below Ground: O Ground Floor Area [sfl: 51,000 Upper Floor Area [sfJ: 51,000 Plan Irregularities? Y diaph discont at 50xtO0 ft atrium opng. Veftical Irregularities? N Column Fy [ksi]:50 Girder Fy [ksi]: 36 Floor Construction Type: MC Web Connection Type: WE SMAW? Flange Weld Process: Number of Frames in Each Direction: NE-SW N-S 2 E-W 3 NW-SE Notes: MRF ConnectionInspection/TestingScope and DamageSummary No of Inspected Floor-Frames: 12 Total No of Corms in Inspected FF’s: 84 54 O?Owl:75.0 ‘%0 No of Connections Inspected: No of Connections Tested: 64 Damage Score :2.21 Number of Floor-Frames in each Damage Class for each inspected/tested Frame. i=zli% T-- NS 14 A NS c Ew E k A-8 Ffiday,January13,1995 NIST Sume of Steel MRF Buildings Affectedby J e NorthridgeEarthquake Smey Form: new Suwey Date: 10/21/94 Pra Nridge Status: OC status as of 10/21/94 BuildingID m inspection/Testin$ 1P Repair/Retmf% w BJ09 Geographic Zone W Northridge Tag: N Non-MRF Structural Damage? NO “none” Non-Structural Damage? life Safety related: Y&3&iiing, condu%mechanicalsystemdamage-for Hospital,thiswas LhBafety OtheK YES “partitions, ceiings, expansionjointmateriaVflashing at adjacentbuildings damaged.” Design Code: T24 CBC 1979 Year Designed:1982 Year Built: MRF StoriesAboveGround:5 MRF StoriesBelowGround:O GroundFloorArea[~ 90,000 UpperFborha [sfJ: 80,000 1983 Plan hagularities? Y reent comers at floor 3 and above. Vertical ha uiarities? Y possib!e mass imeg at floor 3 setback. Column Fy [ks~:50 Gfder Fy [ksil: 36 Floor Construction Type: MC Web Connection Type: B FlangeWeld Process: U Number of Frames in Each Direction: N-S 8 NE-SW NW-SE E-W 8 Notes: MRFConnectionInspection/TestingScope ●nd DamageSummary No of Inspected Floor-Frames: 80 TotalNo of Corms in Inspected FFs: 516 No of Connections Inspected: No of Connections Tested: 133 133 %Wl : 90.0% Damage Score 27 . A-9 Friday,January 13,1995 NIST Survey of Steel MRF Bu~did~~ Affected by the Northridge Earthquake Number of Floor-Frames in each Darnage Class for each inspededltested Frame. A-10 Page A9 Friday,January13,1995 Survey Form: new Pm Nridge Status: NISTSu~ey of Steel MRF Buildings Affectedbythe NodhridgeEarthquake SurveyDate: 10W94 OC Status as of 10MI94 lnspeti”on/Testing: Repair/Retrott BuildingID: Oc C na BJlo ~ Geographic Zone: WH No~ridge Tag: N Non-MRF Structural Damage? NO “None.- Non-Structural Damage? Life Safety related: Other YES “partitions, plumbing, piping, no iii safety impact” Design Code: Unknown Year Designed: 1990 1991 Year Built: Ground Floor Area [sfJ:50,000 Upper Floor Ama [sfj: 50,000 MRF Stories Above Ground: 5 MRF Stones Below Ground: 1 Pla~ Irregularities? Ve~l Column Fy [ksil:50 Girder Fy [ksfl: 36 Floor Construction Type: MCL Web Connection Type: B Flange Weld Process: U Number of Frames in Each Direction: N-S 4 NE-SW E-W 4 NW-SE Notes: MRF Connection Inspection/Testing Total No of Corms in Inspected FF’s: No of Connections Inspected: No of Connections Tested: Irregularities? Scopeand Damage Summary No of Inspected Floor-Frames: 13 %Wl : Damage Score :0.00 86 35 35 Number of Floor-Frames in each Damage Class for each inspacteWtested Frame. Frame Direction Bays Avg Width Flr-Frms 20 EW 4 ; ;2 Ew 20 4 20 4 : 30 3 GN ;’4 30 3 2 GS 3 J NS :: : TG BG 0 o 0 : : t 0 0 0 0 0 A-n 0 0 0 : 0 0 0 ; 0 0 0 0 0 : 0 0 0 0 BW 0 o 0 ! 0 0 s Pz 0 0 0 : 0 0 Cw 0 .: 0 0 0 0 0 0 0 0 0 0 0 NIST Survey 01 Steei MKi- wiamgs Affected by the Northtidge Earthquake Friday, January 13,1995 Suivey Date: 9/30/94 Survey Form: new Pre Nridge Status: Building ID Uc 1P 1P Status as of 9/30/94 Inspection/Testing: Repair/Retrofit UC BJl$ Geographic Zone: W Non-structural Damage? Life Safety related: YES “Required miscellaneous repairs to paint plumbing, etc.” Qther Ground Floor Area [sf’j: 2$,000 Upper FloorArea [sfi: 26,000 MRF Stones Above Ground: 5 MRF Stories Below Ground: 1 Design Code :T24 CBC Year Designed: 1991 1992 Year Built: Plan Irregularities? N VertJcal IrregularMes? Column Fy [ksi]: 50? Girder Fy [ks~: 36? Fioor Construction Type: MC/L? Web Connection Type: WB Flange Weld Process: U Number of Frames in Each Direction: N-S 4 NE-SW E-W 4 NW-SE Notes: MRF ConnectionInspection/TestingScopeand i)amage Summary TotalNo of Corms in Inspected F%: 156 No of Inspected Floor-Frames: 26 No of Connections Inspected: No of Connections Tested: %Wl : 100,0% Damage Score :.98 138 138 Number of Floor-Frames in each Damage Class for each inspectedltested Frame. TG ;2 K 3 CCN Ccs YN Ys NS :: 3 NS : 3 ;; 25 : BG 0 TC 0 A-12 se 0 Tw 0 BW 3 4 s Pz 0 Cw 0 0 Friday, January 13, 1995 Suwey Form: new Pre Nridge Status: NIST Survey of Steel MRF Buildings Affected by the Northridge Earthquake Sutvey Date: 10/13/94 OC Status as of 10/13/94 Inspection/Testing: Repair/Retrofit Building ID: OC C NS BJ18 Geographic Zone: WI-I Northridge Tag: N Non-MRF Structural Dama e? YES “Possible settlemen ? of soil adjacent to basement wall. Block wall minor cracking.” Non-Structural Damage? Ltie Safety related: Othec YES “Exterior cladding cracked. Ceiling damage. Mechanical units shifted off isolators.” Design Code: LABC? Year Designed: 1987 Year Built: 1989 1985? MRF Stories Above Ground: 3 MRF Stories Below Ground: O Ground Floor Area [sfj: 21,000 Upper Flmr Area [sfl: 21,000 Plan Irregularities? Y reent comer, L-shaped floors. Vertical Irregularities? N but note discontinuous top story mlumns landing midspan on floor 3 girders. Column Fy [ksi]:50 Girder Fy [ksi]: 36 Floor Construction Type: MCL Web Connection Type: B Flange Weld Process: U Number of Frames in Each Direction: N-S 3 NE-SW NW-SE E-W 3 Notes: MRFConnectionlnspection~estingScopeand DamageSummary No of Inspected Floor-Frames: 24 TotalNo of Corms in Inspected FF’s: 68 No of Connections Inspected: No of Connections Tested: 68 68 %wl :75.0 % Damage Score :.64 Number of Floor-Frames in each Damage Class for each inspectedltested Frame, mzGNS NS NS Ew Ew Ew Bays Avg Width! Flr-Frms 4 30 4 30 1 4 36 4 30 : 4 3 30 4 36 1 I II A-13 NIST Suwey of Steel MRF Buildings Affected by the Northridge Earthquake Friday, January 13, 1995 Survey Date: 10/10/94 Survey Form: new Pre Nridge Status: OC Status as of 10/10/94 lnspection~esting: Repair/Retrofit Building ID: OC C c DMI Geographic Zone: IAX Northridge Tag: N Non-MRF Structural Damage? NO “None” Non-Structural Damage? Life Safety related: YES “Stair system worked as non-structural building braces and showed damage.” Other Design Code: UBC Year Designed: 1970 Year Built: 1971 YES “Drywall and plaster in stairwells cracked at each floor.” 1969 MRF Stories Above Ground: 15 MRF Stories Below Ground: 2 Ground Floor Area [sfJ:60,000 Upper Flmr Area [sfj: 21,000 Plan Irregularities? N Vertioal Irregularities? Y possible soft story& geom irreg at setback above podium base. Column Fy [ksi]: 50 Girder Fy [ksi]: 36 Floor Construction Type: MC Web Connection Type: W Flange Weld Process: U Number of Frames in Each Direction: N-S 2 NE-SW E-W 2 NW-SE Notes: WIRFConnectionlnspectionKestingScopeand DamageSummary Total No of Corms in Inspected FF’s: 62 No of Inspected Floor-Frames: 5 No of Connections Inspected: 13 Yowl : No of Connections Tested: 13 Damage Score :0.00 Number of Floor-Frames in each Damage Class for each inspected/tested Frame. 4 A H A-14 Friday,January13, 1995 Survey Form: new Pre Nridge Status: NIST Suwey of Steel MRF Buildings Affected by the Northridge Earthquake Survey Date: 9/29/94 OC Status as of 9/29/94 Inspection/Testing: Repair/Retrofit Building ID: Oc C c EQEI Geographic Zone: SC Northridge Tag: YG Non-MRF Structural Damage? YES”2 permanent deflection to south at roof, 1-3/8” at ground ftoor. 1-3/8” permanent defled”on to west at roof, 1“ at ground floor.” Non-Structural Damage? Life Safety related: Other Design Code: UBC Year Designed: 1991 Year Built: 1992 YES “Buckled single angle out+f-plane braces for precast panels. Chipped comers and minor cracking of some precast panels. Some broken glass, dropped ceiling tiles, and partition wall damage.” 1988 MRF Stories Above Ground:4 MRF Stories Below Ground: O Ground Floor Area [sfj: 21,200 Upper Floor Area [sfl: 21,500 Pla~ Irregularities? Vefical Irregularities? Column Fy [ksi]: 50 Girder Fy [ksi] 36 Floor Construction Type: MC Web Connection Type: WB Flange Weld Process: FCAW Number of Frames in Each Direction: NE-SW N-S 2 NW-SE E-W 2 Notes: MRFConnectionlnspection~estingScope and DamageSummary No of Inspected Floor-Frames: 16 TotalNo of Corms in Inspected FF’s: 112 Yowl :0.0 Yo 112 No of Connections Inspected: No of Connections Tested: 112 Damage Score :4.31 Number of Floor-Frames in each Damage Class for each inspected/tested Frame. A-15 NIST Sutvey of Steel MRF Buildings Affected by the Northridge Earthquake Friday, January 13, 1995 Survey Date: 9/29194 Survey Form: new Pre Nridge Status: Oc EQE2 Building ID: Oc Status as of 9/29/94 Inspection/Testing: Repair/Retrofit “ C c Geographic Zone: SC Northridge Tag: YG Non-MRF Structural Damage? YES “4” permanent deflection to Northwest at roof. Crack across diaphragm with 2“ separation. Pullout failure of re-cast attachments. Failure of non-moment beam connection at drop of roof about 4“. Pullout of roof from Elock walls. Pounding damage of block walls with roof diaphragm and with adjacent parking structure.” Non-Structural Damage? Life Safety related: YES “Extensive partition wall, ceiling, and glass damage. Cracked precast panels.” Othec Design Code: UBC Year Designed: 1991 1992 Year Built: 1988 Ground Floor Area [sfj: 27,000 Upper Floor Area [sfJ: 27,000 fvlRF Stories Above Ground: 1 MRF Stones Below Ground: O Plan Irregularities? Y reent comec L-shaped floors. Ve~l irregularities? Column Fy [ksi]:36 Girder Fy [ksi]: 36 Floor Construction Type: MC Web Connection Type: WB FCAW Flange Weld Process: Number of Frames in Each Direction: N-S 3 NE-SW NW-SE E-W 3 Notes: MRF ConnectionInspection/TestingScope and DamageSummary Total No of Corms in Inspected FF’s: No of Connections Inspected: No of Connections Tested: 20 No of Inspected Floor-Frames: 6 20 20 %wl :0.0 % Damage Score :4.17 Number of Floor-Frames in each Damage Class for each inspectedltested Frame. 2L 6L NS NS 1 1 0 0 0 1 0 0 0 0 0 0 A-16 1 1 0 0 0 0 0 0 1 Friday, January 13, 1995 Survey Form: old Pre Nridge Status: NIST Survey of Steel MRF Buildings Affected by the Northridge Earthquake Survey Date: 8/23194 UC Status as of 8/23t94 Inspection/Testing: Repair/Retrofit Building ID: Uc C 1P ESII Geographic Zone WLA Northridge Tag: N Non-MRF Structural Damage? YES “Slip connections reached end of travel at lowest level of bldg. &angles bolted to web were slightly bent.” Non-Structural Damage? Life Safety related: NO “Building not occupied.” Othen Design Code: UBC Year Designed: 1993 Year Built: 1994 NO “None. Cladding not on.” 1991 MRF Stories Above Ground: 5 MRF Stories Below Ground: O Ground Floor Area [sfl: Upper Floor Area [sfJ: 11,800 Plan irregularities? ~~o~ml irreg, reent comers, diaph discontinuity Vertical Irregularities? Y mass irreg at floor setbacks. Column Fy [ksi]:50 Girder Fy [ksi]: 36 Floor Construtilon Type: MCL Web Connection Type: WB Flange Weld Process: FCAW Number of Frames in Each Direction: N-S 5 NE-SW E-W 5 NW-SE Notes: MRF ConnectionInspection/TestingScopeand DamageSumma~ Total No of Corms in Inspected FF’s: No of Connections Inspected: No of Connections Tested: 100 100 100 No of Inspected Floor-Frames 50 %wl :0.0 % DamageScore:.44 Number of Floor-Frames in each Damage Class for each inspectedltested Frame. A-17 NIST Suwey of Steel MRF Buildings Affected by the Northridge Earthquake Friday, Januafy 13,1995 Survey Date: 8/19/94 Survey Form: old Pre Nridge Status: UC Status as of 8/19/94 Inspection/Testing: Repair/Retrofit Building ID: v ES12 Geographic Zone: SM Northndge Tag: N Non-MRF Structural Damage? YES “Buckled rod braces in penthouse. Cracks in non-structural masonry walls.” Non-Structural Damage? Ltie Safety related: NO “None.” Other Design Code: UBC Year Designed: 1990 1993 Year Built: YES “Crocksin non-structural masonry walls.” 1989? MRF Stories Above Ground: 5 MRF Stories Below Ground: O Ground Floor Area [sfl: 21,000 Upper Floor Area [sfl: 21,000 Plan Irregularities? Y reent comers Vefical Irregulatiles? Column Fy [ksi]:50 Girder Fy [ksi]: 36 Floor Construction Type: MCL Web Connection Type: B Flange Weld Process: SMAW Number of Frames in Each Direction: N-S 3 NE-SW E-W 4 NW-SE Notes: MRF Connection Inspection/Testing Total No of Corms in Inspected FF’s: No of Connections Inspected: No of Connections Tested: Scope and Damage Summary 2 2 No of Inspected Floor-Frames ‘/owl :0.0 ‘/0 Damage Score :5.00 Number of Floor-Frames in each Damage Class for each inspected/tested Frame. A A-18 1 Friday, January 13, 1995 NIST Survey of Steel MRF Buildings Affected by the Northridge Earthquake Sutvey Form: new Pre Nridge Status: Suntey Date: 10/3/94 OC Status as of Inspection/Testing: Repair/Retrofit Building ID: Oc 1P 1P ES13 Geographic Zone: UC Northridge Tag: N Non-MRF Structural Dama e? YES “Diagonal braces at% echanical Penthouse above Main Roof had caused beam web to tear and beam bolts to shear off.” Non-Structural Damage? Life Safety related: YES “Mechanical equipment at Penthouse had damaged isolators. Exterior stucco tore away from studs @ Penthouse.” Othen Design Code: UBC Year Designed: 1984 Year Built: YES “Cracked non-structural interior partitions.” 1982 MRF Stories Above Ground: 8 MRF Stories Below Ground: 2 Ground Floor Area [sfJ: Upper Floor Area [sfj: 8,000 Plan Irregularities? N Vertical Irregularities? N Column Fy [ksi]: Girder Fy [ksi]: Floor Construction Type: MCL Web Connection Type: B Flange Weld Process U Number of Frames in Each Dkection: NE-SW 1 N-S 1 NW-SE 1 E-W Notes: MRF ConnectionInspection/TestingScopeand DamageSummary No of Inspected Floor-Frames: 1 TotalNo of Corms in Inspected FF’s 12 Yowl :100.0 ‘%0 No of Connections Inspected: 12 No of Connections Tested: 3 Damage Score :4.50 Number of Floor-Frames in each Damage Class for each inspectedltested Frame. A A-19 NIST Survey of Steel MRF Buildings Affected by the Northridge Earthquake Friday, January 13, 1995 Survey Date: 8125194 Survey Form: old Pre Nridge Status: ES14 Building ID: LM U u Status as of 6/1/94 Inspection/Testing: Repair/Retrofit LM? Geographic Zone: WLA Northridge Tag: N Non-MRF Structural Damage? NO “None reported.” Non-Structural Damage? Life Safety related: NO “None.” YES “May have been some drywall separation &/or cracks.” Othec Design Code: UBC Year Designed: 1988 1991 Year Built: 1985 Ground Floor Area [sfJ: Upper Floor Area [sfJ 13,500 MRF Stories Above Ground: 27 MRF Stories Below Ground: 2 Plan Irregularities? Y reent comers Vertical Irregularities? N Column Fy [ksi]: 50 Girder Fy [ksi]: 36 Floor Construdlon Type: MCL Web Connection Type: WB Flange Weld Process: U Number of Frames in Each Direction: N-S 2 NE-SW E-W 2 NW-SE Notes: NOTE: NS times “bend in plan, are not in single vertical plane. EW frames differ in orientation by about 40 degrees, but resultant is normal to resultant of NS MRF ConnectionInspection/TestingScopeand DamageSummary Total No of Corms in Inspected FF’s: No of Connections Inspected: No of Connections Tested: 72 20 14 No of Inspected Floor-Frames: 10 ‘?/owl :10.0 %0 Damage Score :1.54 Number of Floor-Frames in each Damage Class for each inspectedltested Frame. A : D NESW NESW 2 0 0 4 A-20 0 0 2 : 0 Friday, January 13, 1995 NIST Survey of Steel MRF Buildings Affected by the Northridge Earthquake Su~ey Form: comb Suwey Date: 10/7/94 Pre Nridge Status: Status as of 9/6194 Inspection/Testing: Repair/Retrofit OC Building ID: Oc C NS ES15 Geographic Zone: SM Northridge Tag: G N~bM,~-Mn~uctural Damage? Non-Structural Damage? Ltie Safety related: “Unknown” Othec Design Code: UBC Year Designed: 1989 Year Built: 1990 “Unknown” 1985 MRF Stones Above Ground:6 MRF Stories Below Ground: O Ground Floor Area [sfj: 18,000 Upper Floor Area [sfl: 15,000 Plan Irregularities? Y out-of-plane offsets at floor 5. Vertical Irregularities? Yin plane discontinuity at floor 5. Column Fy [ksiJ:50 Girder Fy [ksi]: 36 Floor Construction Type: MCUMC Web Connection Type: B Flange Weld Process: SMAW Number of Frames in Each Direction: N-S NE-SW 4 E-W NW-SE 2 Notes: At floors 1-4,2 2-bay NWSE frames. At firs 5-7,4 l-bay NWSE frames. MRF ConnectionInspection/TestingScopeand DamageSummary TotalNo of Corms in Inspected FF’s 112 No of Inspected Floor-Frames 46 No of Connections Inspected: No of Connections Tested: 105 105 %wl :30.0 ‘?/0 Damage Score :2.51 Number of Floor-Frames in each Damage Class for each inspectedltested Frame. A-21 NIST Suwey of Steel MRF Buildings Affected by the Northridge Earthquake Friday, January 13, 1995 Survey Date: 9/24/91 Survey Form: new Pre Nridge Status: OC Status as of 6/21/94 Inspection/Testing: Repair/Retrofit ES17 Building ID: Oc C c Geographic Zone: SO Northridge Tag: N Non-MRF Structural Dama e? YES “75’ CMU block wal Pon property line& part of exterior enclosure for building had expansion bolts which tie wall to building shear off, Wall pulled away from building at top (42’ above ground floor) approximately 2“.” Non-Structural Damage? Life Safety related: YES “Exterior plaster soffit above main street entrance considerable cracking (sic). Access to this entrance limited.” Other Design Code: LABC Year Designed: 1989 Year Built: 1990 1988 MRF Stones Above Ground: 3 MRF Stones Below Ground: O Ground Floor Area [sfJ: 15,500 Upper Floor Area [sfj: 15,500 Plan Irregularities? Y reent comers: L-shaped floors. Vefical Irregularities? Column Fy [ksi]: 50 Girder Fy [ksi]: 36 Floor Construction Type: MC Web Connection Type: B Flange Weld Process: FCAW Number of Frames in Each Direction: N-S 3 NE-SW E-W 3 NW-SE Notes: MRF ConnectionInspection/TestingScopeand DamageSummary TotalNo of Corms in Inspected FF’s: 26 No of Inspected Floor-Frames: 13 No of Connections Inspected: No of Connections Tested: 26 12 O/owl :0.0 ‘-!/0 Damage Score :.65 Number of Floor-Frames in each Damage Class for each inspected/tested Frame. A-22 . “ Friday, January 13, 1995 NIST Survey of Steel MRF Buildings Affected by the Northridge Earthquake Survey Form: new Suwey Date: 9/24/91 Pre Nridge Status: VAC Status as of 9/24/94 Inspection/Testing: Repair/Retrofit Building ID: VAC C NS ES18 Geographic Zone WI-I Northridge Tag: N Non-MRF Structural Dama e? YES “Same location on 2 -5 floors, non frame beam mnnection at a diagonal comer has weld cracks at shear tab to column.” Non-Structural Damage? Life Safety related: Othen YES “No damage except one pane of glass broke on 2nd floor. NOTE: Interior spaces not built out.” Design Code: LABC Year Designed: 1987 1990 Year Built: 1985 MRF Stories Above Ground: 25 MRF Stories Below Ground: O Ground Floor Area [sfl: 27,500 Upper Floor Area [sO: 26,500 Plan Irregularities? Y reent comers. Vertical Irregularities? N Column Fy [ksi]:50 Girder Fy [ksi]: 36 Floor Construction Tyw Web Connection Ty~. Flange Weld Process Number of Frames in Each Direction: N-S 3 NE-SW 1 E-W 3 NW-SE 2 Notes: MC B FCAW MRF ConnectionInspection/TestingScopeand DamageSummary No of Inspected Floor-Frames: 216 TotalNo of Corms in Inspected FF’s: 864 No of Connections Inspected: No of Connections Tested: 864 829 ‘hW1 :80.0 ~0 Damage Smre :.49 Number of Floor-Frames in each Damage Class for each inspected/tested Frame. A-23 NIST Suwey of Steel MRF Buildings Affected by the Northridge Earthquake Friday, January 13, 1995 Survey Date: 10/12/94 Survey Form: new Pre Nridge Status: Status as of 10/12/94 Inspection/Testing: Repair/Retrofit OC Building ID: OC C na Northridge Tag: N Non-MRF Structural Damage? YES “Some minor cracks tn shear walls. (LandersEQ[1992] FEI Geographic Zone: WL4 caused more cracks than Northridge EQ.)” Non-Structural Damage? Life Safety related: YES “Some ceiling tiles fell. other damage unknown by FE [survey engineer firm].” Other Design Code: LABC? Year Designed: 1965 1966 Year Built: 1964 Ground Floor Area [sfj: 30,000 Upper Floor Area [sfj: 23,000 MRF Stories Above Ground: 17 MRF Stories Below Ground: O Plan Irregularities? Y out-of-plane offset at base Vertical Irregularities? N Column Fy [ksi]:36 Girder Fy [ksi]: 36 Floor Construction Type: MC Web Connection Type: W FCAW Flange Weld Process: Number of Frames in Each Diretilon: N-S O NE-SW NW+E E-W 2 Notes: NS direction is Shear Wall System MRF ConnectionInspection/TestingScopeand DamageSummary Total No of Corms in Inspected FF’s: No of Connections Inspected: No of Connections Tested: 88 12 No of Inspected Floor-Frames: 4 %W1 : 12 Damage Smre :0.00 Number of Floor-Frames in each Damage Class for each inspected/tested Frame. P u EW EW 1! :: : : : A-24 : o 0 Friday, January 13, 1995 NIST Survey of Steel MRF Buildings Affected by the Northridge Earthquake Survey Form: new Pre Nridge Status: SuNey Date: 9/28194 OC JAM7480 Building ID: Oc Status as of 9128194 Inspection/Testing: Repair/Retrofit 1P NS Geographic Zone: WIA Northridge Tag: N Non-MRF Structural Dama e? YES Per EQE letter of h 94: “some horizontal cracks at mncrete revering of a steel column along the east wall of the DWP vault ... at the steel beam Conneti’on to the column.” Non-Structural Damage? Life Safety related: YES Per EQE letter 2/2/94: “Three elevators were shutdown. No additional damage to building support equipment reported. A fevvsuppotis were lost at some sprinkler lines in the all ... in various staiway locations as well as glass parking garage. Cracks in the d Othen damage at the front door ... cracl“”ing to non-bearing cmu block walls in stahvay #1 .“ Design Code: LABC Year Designed: 1983 1984 Year Built: Ground Floor Area [sfJ:32,000 Upper Floor Area [sfJ: 23,000 MRF Stories Above Ground: 11 MRF Stories Below Ground: O Plan Irregularities? Y possible reent mmers Vertical Irregularities? Y mass geom irregs due to many setbacks Column Fy [ksi] Girder Fy [ksi]: 36 Floor Construction Type: MC Web Connection Type: B Flange Weld Process: U Number of Frames in Each Direction: NE-SW N-S 4 E-W 4 NW-SE Notes: MRF ConnectionInspection/TestingScopeand DamageSummary Total No of Corms in Inspected FF’s: No of Connections Inspected: No of Connections Tested: No of Inspected Floor-Frames: 14 %Wl : 33.0% Damage Score :2.81 116 83 83 Number of Floor-Frames in each Damage Class ftx each inspectedtested Frame. lw 2 EW 6 9 g Ew ~ H M NS NS NS 4 4 i 4 4 3 2 0 0 0 ‘2 2 0 0 0 A-25 BW S Pz [ Cw o 1 0 0 0 c NIST Survey of Steel MRF Buildings Affected by the Northridge Earthquake Friday, January 13, 1995 Survey Date: 9127194 Suwey Form: new Pre Nridge Status: Status as of 9/27194 Inspection/Testing: Repair/Retrofit OC Building ID: C 1P JAM7482 Geographic Zone: SO Northridge Tag: Y Non-MRF Structural Damage? YES “Base pi’s set flush mto ground floor slab, supported by RC COISbelow mncrete around inset PL typically spalled.” Non-Structural Damage? Life Safety related: Othen Design Code: LABC Year Designed: 1983 1984 Year Built: 1980 MRF Stories Above Ground:4 MRF Stories Below Ground: O Ground Floor Area [sq: 17,000 Upper Floor Area [sfJ: 14,200 Plan Irregularities? Y possible reent comers Ve~cal Irregularities? Column Fy [ksi]:36 Girder Fy [ksi]: 36 Floor Construction Type: W Web Connection Type: B Flange Weld Process U Number of Frames in Each Direction: N-S 3 NE-SW E-W 4 NW-SE Notes: MRF ConnectionInspection/TestingScopeand DamageSummary No of Inspected Floor-Frames: 28 TotalNo of Corms in Inspected FF’s: 88 %wl :50.0 %0 Damage Score :1.39 88 88 No of Connections Inspected: No of Connections Tested: Number of Floor-Frames in each Damage Class for each inspectedltested Frame. Frame Direction EW : 4EW E ~ B E NS NS NS 1 ; 2 ; 2 24 26 4 26 28 22 33 33 4 A-26 Friday, Januafy 13, 1995 Sunmy Form: new Pre Nridge Status: NIST Suwey of Steel MRF Buildings Affected by the Northridge Earthquake Survey Date: 9/26/94 OC Status as of 9/26/94 lnspection~esting: Repair/Retrofit Building ID: VAC C 1P JAM7484 Geographic Zone SO Noithridge Tag: Y Non-MRF Structural Damage? ~~~ ;Distortion to beam web & shear tab in a few nonframe connections. 2-3.5” out-of plumb, northerly, at 4th Non-Structural Damage? Life Safety related: Othec Design Code: Year Designed: 1985 Year Built: 1985 MRF Stories Above Ground:4 MRF Stories Below Ground: O Ground Floor Area [sfl: 15,900 Upper Flmr Area [sfi 15,900 Plafl Irregularities? Vertical Irregularities? N Column Fy [ksi]: 36 Girder Fy [ksi]: 36 Floor Construction Type: MCL Web Connection Type: B Flange Weld Process: U Number of Frames in Each Direction: NE-SW N-S 2 E-W 2 NW-SE Notes: MRF ConnectionInspection/TestingScopeand DamageSummary Total No of Corms in Inspected FF’s: 40 40 No of Connections Inspected: 40 No of Connections Tested: No of Inspected Floor-Frames: 20 9’Owl:50.0 Yo Damage Score :2.40 Number of Floor-Frames in each Damage Class for each inspectedltested Frame. A-27 NIST Survey of Steel MRF Buildings Affected by the Northridge Earthquake Friday, January 13, 1995 Suwey Form: new l% Nridge Status: Survey Date: 9/26/94 Building ID: Status as of 9/26/94 Inspection/Testing: Repair/Retrofit OC JAM7485 C Geographic Zone WLA Northridge Tag: NY Non-MRF Structural Damage? NO “per EQE, ‘no structural damage’ as of 1/29/94 walk-through” Non-Structural Damage? Life Safety related: YES “Per EQE letter 1/29: ‘drywall cracked inside the stainvay, and an architectural facade was cracked. Instances of broken glass were also noted.’” Othec Design Code: LABC Year Designed: 1984 Year Built: 1984 1980 MRF Stories Above Ground:4 MRF Stories Below Ground: O Ground Floor Area [sfj: 12,200 Upper Floor Area [sfl: 12,200 Plan Irregularities? N Vertkal Irregularities? N Column Fy [ksi]:36 Girder Fy [ksi]: 36 Floor Construction Type: MCL Web Connection Type: B Flange Weld Process: U Number of Frames in Each Dired”on: N-S 2 NE-SW E-W 3 NW-SE Notes: MRF ConnectionInspection/TestingScope and DamageSummary TotalNo of Corms in Inspected FF’s: 103 No of Inspected Floor-Frames: 25 No of Connections Inspected: No of Connections Tested: 103 103 f!!owl :40.0 0/0 Damage Smre :2.03 Number of Floor-Frames in each Damage Class for each inspected/tested Frame. -lW Ew 2 4 Ew 2 A G NS NS ; ;! 20 20 5 5 0 0 A-28 Friday, Januaty 13, 1995 Sutvey Form: new Pre Nridge Status: NIST Survey of Steel MRF Buildings Affected by the Northridge Earthquake . Suwey Date: 10/14/94 OC Status as of 10/21/94 inspection/Testing: Repair/Retrofit Building ID: OC C na JAM7486 Geographic Zone: WLA Northridge Tag: N NonbMn~n~~ructural Damage? Non-Structural Damage? Life Safety related: Othen Design Code: LABC Year Designed: 1983 Year Built: 1984 YES “Per EQE letter repom cracking in staitway drywall.” 1980 MRF Stories Above Ground: 13 MRF Stories Below Ground: O Ground Flmr Area [so: 20,000 Upper Floor Area [sfJ: 16,000 Pla~ Irregularities? Vertical Irregularities? Y possible mass irreg at floor 6 setbackldeck type change Column Fy [ksi]:50 Girder Fy [ksi]: 36 Floor Construction Type: MC Web Connection Type: B Flange Weld Process: U Number of Frames in Each Direction: N-S NE-SW 2 NW-SE 2 E-W Notes: MRF ConnectionInspection/TestingScopeand DamageSummary Total No of Corms in Inspected FF’s: No of Connections Inspected: No of Connections Tested: 294 114 114 No of Inspected Floor-Frames: 44 %wl :100.0 ?40 Damage Score :.11 Number of Floor-Frames in each Damage Class for each inspected/tested Frame. A-29 NIST Survey of Steel MRF Buildings Affected by the Northridge EaRhquake Friday, January 13, 1995 Survey Form: new Pre Nridge Status: Survey Date: 10/12/94 Status as of 10/21/94 Inspection/Testing: Repair/Retrofit OC JAM7487 Building ID: OC C na Geographic Zone: SO Northridge Tag: N Non-MRF Structural Dama e? NO “none” noted by EQ z or JAMA, but not out-of-plumb 2 northerly at top, possibly pre-Notthridge and not associated with any other damage. Non-Structural Damage? Life Safety related: Othec YES “Per EQE letter report, minor only, cracking in stainvay drywall.” Design Code: LABC Year Designed: 1979 Year Built: 1976 Ground Floor Area [sfj: 12,500 Upper Floor Area [sfJ: 15,500 MRF Stories Above Ground: 12 MRF Stories Below Ground: O Plan Irregularities? Y reent mmers & diaph discont @ patial floors 2 and 3. Vertical Irregularities? Y possible soft sto~ at tall columns, floor 2 & 3 mezzanine/patial floor Column Fy [ksi]:36 Girder Fy [ksi]: 36 Floor Construction Type: MCL Web Connection Type: B Flange Weld Process: U Number of Frames in Each Direction: N-S 2 NE-SW E-W 2 NW-SE Notes: MRF ConnectionInspection/TestingScopeand DamageSummary Total No of Corms in Inspected FF’s: No of Connections Inspected: No of Connections Tested: 326 94 94 No of Inspected Floor-Frames 41 O/owl:100.0 ‘%0 Damage Score :.18 Number of Floor-Frames in each Damage Class fix each inspected/tested Frame. Tw : : 0 NS NS 3 0 : A-30 BW 0 o 0 3 4 2 s Pz 0 0 0 Cw 0 0 0 0 Friday, January 13, 1995 Suwey Form: new Pre Nridge Status: NIST Survey of Steel MRF Buildings Affected by the Northridge Earthquake Survey Date: 10/14/94 OC Status as of 10/21/94 lnspeti}on/Testing: Repair/Retrofit Building ID: OC C na JAM7489 Geographic Zone: SO IUorthridge Tag: N N~GM~~nS~ructurai Damage? Non-Structural Damage? Lfle Safety related: Othec Design Code: LABC Year Designed: 1979 1979 Year Built: YES “Per EQE letter repom cracking in staitway drywall, planter (on grade?) slightly settled.” 1976 MRF Stories Above Ground:6 MRF Stories Below Ground: O Ground Floor Area [sfl: 21,000 Upper Floor Area [sfj: 21,000 Plan Irregularities? Y reent comers T-shape floors Vertical Irregularities? N Column Fy [ksi]:36 Girder Fy [ksi]: 36 Floor Construction Type: MCL Web Connection Type B Flange Weld Process U Number of Frames in Each Direction: N-S 4 NE-SW E-W 5 NW-SE Notes: MRFConnectionInspectionfiestingScopeand DamageSumma~ TotalNo of Corms in Inspected FF’s: 54 No of Inspected Floor-Frames: 7 No of Connections Inspected: No of Connections Tested: 8 8 %wl : Damage Score :0.00 Number of Floor-Frames in each Damage Class for each inspected/tested Frame. A-31 NIST Survey of Steel MRF Buildings Affected by the Northridge Earthquake Friday, Januaty 13, 1995 Survey Date: 913194 Survey Form: old Pre Nridge Status: Status as of 9/3/94 Inspection/Testing: Repair/Retrofit OC Oc C 1P Geographic Zone: WH Northridge Tag: N Non-MRF Structural Damage? YES “Broken H.S. bolts in tie beam@ roof level.” Non-Structural Damage? Life Safety related: NO Othec YES “Damaged masomy veneer@ comers of bldg on exterior.” Design Code: LABC Year Designed: 1978 Year Built: 1976 ‘ MRF Stories Above Ground:4 MRF Stories Below Ground: O Ground Floor Area [sfl: Upper Floor Area [sfj: 27,600 Plan Irregularities? Vertical Imegularities? Column Fy [ksi]: 36 Girder Fy [ksi]: 36 Floor Construction Type: MC Web Connection Type: B Flange Weld Process: SMAW Number of Frames in Each Direction: N-S NE-SW E-W NW-SE Notes: MRF Connection Inspection)Testing Scope and Damage Summary Total No of Corms in Inspected FF’s: No of Inspected Floor-Frames: 12 ‘/owl :20.0 %0 Damage Score :3.32 102 102 102 No of Connections Inspected: No of Connections Tested: Number of Floor-Frames in each Damage Class for each inspected/tested Frame. 2 8EW A F EW l-l; 2 % : A-32 Friday, Januaty 13, 1995 NIST Survey of Steel MRF Buildings Affected by the Northridge Earthquake Su~ey Form: old Survey Date: 8/18194 Pre Nndge Status: Status as of Inspection/Testing: Repair/Retrofi Building ID: KAR3 1P Geographic Zone: SO Northridge Tag: Non-MRF Structural Dama e? YES “...measured deflec ! Ion of 3-1/2” of the top relative to the base [of 18-story N-S frame. All the deformation is within the top six stories.1” Non-Structural Damage? Life Safety related: Design Code: Year Designed: Year Built: MRF Stories Above Ground: 17 MRF Stories Below Ground: Ground Floor Area [sfj: Upper Floor Area [s0: Plan Irregularities? N Vefioal Irregularities? Column Fy [ks~:36 Girder Fy [ksi]: 36 Floor Construction Type MC/L? Web Connection Type: Flange Weld Process: Number of Frames in Each Direction: N-S 2 NE-SW E-W 2 NW-SE Notes: Ac~c~dmpass directions need to be MRFConnectionInspection/TestingScopeand DamageSummary Total No of Corms in Inspected FF’s: No of Connections Inspected: No of Connections Tested: No of Inspected Floor-Frames Yowl :0.0940 Damage Score :2.00 Number of Floor-Frames in each Damage Class for each inspected/tested Frame. A-33 3 NIST Survey of Steel MRF Buildings Affected by the Northridge Earthquake Friday, January 13, ~995 Survey Form: old Pre Nridge Status: Survey Date: 8/22/94 OC Status as of 8/22/94 Inspection/Testing: Repair/Retrofit Building ID: Oc 1P NS KPFFIA Geographic Zone: SC Northridge Tag: N Non-MRF Structural Damage? Non-Structural Damage? Life Safety related: Othec YES “glazing, ceilings” Design Code: Title 24 Year Designed: 1981 Year Built: MRF Stories Above Ground: 2 MRF Stories Below Ground: O Ground Floor Area [sfl: 9,700 Upper Floor Area [sfl: 9,700 Plan Irregularities? N Vertical Irregularities? N Column Fy [ksi]: Girder Fy [ksi]: Floor Construction Type: MCL Web Connection Type: B Flange Weld Process: U Number of Frames in Each Direction: N-S 2 NE-SW E-W 2 NW-SE Notes: IMRF ConnectionlnspectionlTestingScopeand DamageSummary No of Inspected Flmr-Frames: 4 TotalNo of Corms in Inspected FF’s: 20 No of Connections Inspected: No of Connections Tested: 14 14 %WI :60.0 ‘%0 Damage Smre :.68 Number of Floor-Frames in each Damage Class for each inspectedltested Frame. A-34 BUSTSuwey of Steel MRF Buildings Affected by the Northridge Earthquake Friday, January 13, 1995 Survey Form: old Pre Nridge Status: Suwey Date: 8/23/94 UC Status as of 8/23/94 Inspection/Testing: Repair/Retrofit Building ID: Oc 1P 1P LCIB Geographic Zone NR Nodhridge Tag: R Non-MRF Structural Damage? YES “sheared bolts in moment-frame seated beam connection.” Non-Structural Damage? Ltie Safety related: NO “None observed Othec YES “Extensive damage to interior gypsum board finishes and exterior stucco, buckled parapet copings and displaced seismic joints.” Design Code: Unknown 1988 Year Designed: 1990 1994 Year Built: MRF Stories Above Ground:4 MRF Stones Below Ground: O Plan Irregularities? yaf~~msnnt diaph discont at atrium, but reported Ground Floor Area [sfl: Upper Floor Area [st 31,050 Vertiti~in;~ularities? as Number of Frames in Each Direction: N-S NE-SW 6 NW-SE 8 E-W Notes: Column Fy [ksi]: 36 Girder Fy [ksi]: 36 Floor Construction Type: MCL Web Connection Type: B SMAW Flange Weld Process: MRF Connectionlnspection~estingScopeand DamageSummary No of Inspected Floor-Frames: TotalNo of Corms in Inspected FF’s: 240 No of Connections Inspected: No of Connections Tested: 240 240 ‘A3wl :5.0 ‘h Damage Smre: Number of Floor-Frames in each Damage Class for each inspected/tested Frame. A-35 NIST Survey of Steel MRF Buildings Affected by the Northridge Earthquake Friday, January 13, 1995 Survey Date: 9/1/94 Survey Form: old Pre Nridge Status: UC Status as of 9/1/94 Inspection/Testing: Repair/Retrofit Building ID: Oc 1P 1P LCIE Geographic Zone: NR Northndge Tag: R Non-MRF Structural Damage? NO “None observed.” Non-Structural Damage? Life Safety related: NO “None observed.” Othec YES “Extensive damage to interior gypsum board finishes and exterior stucco. Brick tile finishes adjacent to west stair support damaged due to movement.” Design Code: Unknown 1988 Year Designed :1990 Year Built: 1994 MRF Stories Above Ground: 3 MRF Stories Below Ground: O Ground Floor Area [sfl: 26,640 Upper Floor Area [sfj: 15,300 Plan Irregularities? Y apparent reent comers, but reported as Unknown Vertical Irregularities? Unknown Column Fy [ksi]: 36 Girder Fy [ksi]: 36 Floor Construction Type: MCL Web Connection Type: B Flange Weld Process: SMAW Number of Frames in Each Dire~”on: N-S 8 NE-SW E-W 11 NW-SE Notes: MRF ConnectionInspection/TestingScopeand DamageSummary No of Inspected Floor-Frames: 2 TotalNo of Corms in Inspected FF’s: 164 No of Connections Inspected: No of Connections Tested: 164 164 %owl :0.0 0/0 Damage Score: Number of Floor-Frames in each Damage Class for each inspected/tested Frame. A-36 Friday, January 13, 1995 NIST Survey of Steel MRF Buildings Affected by the Northridge Earthquake Survey Form: old Pre Nridge Status: Survey Date: 8/18/94 OC Status as of 8/17/94 Inspection/Testing: Repair/Retrofit Building ID: Oc 1P Ns MNH02 Geographic Zone: WH Northridge Tag: G Non-MRF Structural Dama e? NO “As of yet, no others L ctural damage has been observed.” Non-Structural Damage? Life Safety related: NO Other Design Code: LABC Year Designed: 1984 1985 Year Built: YES Loss of glazing at first and second floors, stucco cracking around windows and comers (slight to moderate), dropped ceiling tiles,ovettumed furniture & bookcases. 1980 MRF Stories Above Ground: 3 MRF Stories Below Ground: O Ground Floor Area [sfJ: Upper Floor Area [sfj: 30,900 Plan Irregularities? Y reent comers Vertical Irregularities? N Column Fy [ksi]: 36 Girder Fy [ksi]: 36 Floor Construction Type: MC Web Connection Type: B Flange Weld Process FCAW Number of Frames in Each Direction: N-S 4 NE-SW E-W 2 NW-SE Notes MRF ConnectionInspection/TestingScopeand DamageSummary No of Inspected Floor-Frames 16 TotalNo of Corms in Inspected FF’s 88 No of Connections Inspected: No of Connections Tested: 56 56 %wl :75.0 ‘%0 Damage Score :1.67 Number of Floor-Frames in each Damage Class for each inspectedhested Frame. A D F A-37 NIST Swvey of Steel MRF Buildings Affected by the Northridge Earthquake Friday, January 13, 1995 Survey Form : comb Survey Date: 10/4/94 Pre Nridge Status: Status as of 8/1/94 Inspection/Testing: Repair/Retrofit OC Building ID: Oc C c MNH03AB Geographic Zone: WLA Northridge Tag: N Non-MRF Structural Damage? YES “Minor spalling of concrete @ expansion joints for subterranean parking. Corbel at joint provides vertical support for 14’ trib 2-way slab. Concrete spalled ftom corbel causing partial loss of support.” Non-Structural Damage? Life Safety related: YES “All common exits remained open and unobstructed; however, ... overturned filing cabinets, bookcases, cubicle partitions, etc. blocked hallways and corridors in tenant Othec ~S~~all/steel stud walls out of plumb,.numerous falling T-bar track and tiles, minor window cracking, HVAC cooling towers spring isolators broke.” ALSO: see LS-related damage regarding overturned furnishings. Design Code: LABC Year Designed: 1978 Year Built: 1979 1976 MRF Stories Above Ground: 3 MRF Stories Below Ground: O Ground Floor Area [sfj: 11,200 Upper Floor Area [sfl: 11,200 Plan Irregularities? N Vertical Irregularities? N Column Fy [ksi]:36 Girder Fy [ksi]: 36 Floor Construction Type: W Web Connection Type: B Flange Weld Process: U Number of Frames in Each Direction: N-S NE-SW 6 E-W NW-SE 8 Notes: MRF ConnectionInspection/TestingScope and DamageSummary Total No of Corms in Inspected FF’s: 148 No of Inspected Floor-Frames: 38 No of Connections Inspected: 76 %W1 :0.0 0/0 Damage Score :.28 No of Connections Tested: o Number of Floor-Frames in each Damage Class for each inspected/tested Frame. Friday,January13,1995 NIST Suwe of Steel MRF Buildings AffectedbyJ e Northridge Earthquake Survey Form: comb Suwey Date: 10/4/94 Pre Nridge Status: OC status as of 6/1/94 ins-eating Repair/Retrotit Building ID Oc MNH03CDE C c *@k zone WA Northridge Tag: N Non-MRF Structural Damage? YES “Minor spallin of concrete@ expansion joints for subterranean Pafkin . Coo~~Wbo~ provides vertical support for 14’ Mb ! -way slab. Concrete spalied from corbel causing partial L No@rmtural Damage? however, ... overturned fifing i-de Safety related YES “All common ex”ti remained open andunobstructed@ cabinets, bookcases, cub~ partitions, etc. blocked hallways and corridors in tenant ~$~~lihkal stud walls out of plumb numemusfallin~T-bartmkand tiles, minor window cracking, HVAC coolin towers sp~ng isolatorsbro e.” ALSO: see LS-related damage regarding overturned & mishings. Othec Design Code: LABC Year Designed: 1978 1979 Year Built: 1976 MRF Stones Above Ground:3 MRF Stories Beiow Ground: O Ground Floor Area [~: 17,000 Upper Floor Area [sfi 17,000 Plan Irregularities? Y reent comers Ve~cal In-egularities? Column Fy [ksfl:36 Girder Fy [ksil: 36 Floor Construction Type: W Web Connection Type: B Flange Weld Process: U Number of Frames in EachDirection: N-S NE-SW 14 E-W NW-SE 13 Notes: MRF Connection Inspection/Testing Total No of Corms in Inspected FF’s No of Connections Inspected: No of Connections Tested: Scope●nd Damage SummaIy 304 164 o *O of Inspected Floor-Frames 77 %Wl :0.0% Damage Score :.22 Number of Floor-Frames in each Damage Class for each inspectadltested Frame. Frame 10 11 12 13 14 15 16 17 18 19 20 21 Direction NWSE NWSE NWSE NWSE NWSE NWSE NWSE NWSE NWSE NWSE NWSE NWSE NWSE NESW NESW NESW T 9 G H A-39 . ..- NIST $urve of Steel MRF Buildings Affected by tl e Northridge Earthquake Friday,Januaf’y13,1995 J NESW NESW NESW ;::: NESW NESW ;::; NESW It u 18 18 18 18 18 18 18 3 3 3 3 3 1 i! a : 0 0 0 Q 1 o Ill o 0 0 0 0 0 Ii o 0 0 . A-40 Friday, January 13,1995 NIST Suwey of Steel MRF Buildings Affected by the Northridge Earthquake Survey Form: comb Survey Date: 1014194 Pre Nridge Status: Status as of 8/1/94 Inspection/Testing: Repair/Retrofit OC . a,it MNH03F Building ID: Oc C c ~~ Geographic Zone: WLA Notthridge Tag: N Non-MRF Structural Damage? YES “Minor spalling of concrete @ expansion joints for subterranean parking. Corbel at joint provides vertical support for 14’ trib 2-way slab. Concrete spalled from corbel causing partial loss of support.” Non-Structural Damage? Life Safety related: YES “All common exits remained open and unobstructed; however, ... overturned filing cabinets, bookcases, cubicle patiitions, etc. blocked hallways and mrridors in tenant %%%&all/steelstud walls out of plumb, numerous falfin~T-bartrack and tiles, minor window cracking, HVAC coolin towers spring isolators bro e.” ALSO see LS-related damage regarding overturned & mishings. Othec Design Code: LABC Year Designed: 1978 1979 Year Built: 1976 Ground Floor Area [sfl: 5,600 Upper Floor Area [sfl: 5,600 MRF Stories Above Ground: 3 MRF Stories Below Ground: O PlaJ Irregularities? Vertical Irregularities? N Column Fy [ksi]:36 Girder Fy [ksi]: 36 Floor Construction Type: W Web Connection Type: B Flange Weld Process: U Number of Frames in Each Direction: N-S NE-SW 3 E-W NW-SE 4 Notes: MRFConnectionInspection/TestingScopeand DamageSummary No of Inspected Floor-Frames 17 TotalNo of Corms in inspected FF’s: 86 No of Connections Inspected: No of Connections Tested: 44 ‘Awl :0.0 Yo Damage Score :.26 o Number of Floor-Frames in each Damage Class for each inspected/tested Frame. Avg Width Flr-Frms TG TC BG 22 Tw BC 0 0 0 0 : ; BW 0 s~Pz 0 0 1 0 : Cw a ;5 k NWSE NESW NESW NESW 3 3 3 3 ;: 23 23 2 3 3 3 0 0 : A-41 : 1 0 0 a : 0 NIST Suwey of Steel MRF Buildings Affected by the Northndge Earthquake Friday, January 13, 1995 Survey Form: comb Survey Date: 10/4/94 Pre Nridge Status: Status as of 811194 Inspection/Testing: Repair/Retrofit OC Building ID: Oc MNH03G C c Geographic Zone: WLA Northridge Tag: N Non-MRF Structural Damage? YES “Minor spatting of concrete@ expansion joints for subterranean parking. Corbel at joint provides vertical support for 14’ trib 2-way slab. Concrete spalled from mrbel causing partial loss of support” Non-Structural Damage? Life Safety related: YES “All common exits remained open and unobstructed; however, ... overturned filing cabinets, bookcases, cubicle partitions, etc. blocked hallways and com”dors in tenant Other w~~~allhteel stud walls”out of plumb, numerous falling T-bartrack and tiles, minor window cracking, HVAC cooling towers spring isolators broke.” ALSO: see LS-related damage regarding overturned furnishings. Design Code: LABC Year Designed: 1978 Year Built: 1979 1976 MRF Stories Above Ground: 3 MRF Stories Below Ground: O Ground floor Area [s~: 4,500 Upper Floor Area [s~: 4,500 Plan Irregularities? N Vertical Irregularities? N Column Fy [ksi]:36 Girder Fy [ksi]: 36 Floor Construction Type: W Web Connection Type: B Flange Weld Process: U Number of Frames in Each Direction: N-S NE-SW 2 E-W NW-SE 2 Notes: MRF ConnectionInspection/TestingScope and DamageSummary TotalNo of Corms in Inspected FF’s: 72 No of Inspected Floor-Frames: 42 No of Connections Inspected: No of Connections Tested: 32 o YowA :0.0 ‘?!0 Damage Score :.13 Number of Floor-Frames in each Damage Class for each inspected/tested Frame. A-42 Friday, January 13, 1995 NIST Sutvey of Steel MRF Buildings Affected by the Northridge Earthquake Survey Form: comb Survey Date: 10/4/94 Pre Nridge Status: OC Status as of 8/1/94 Inspection/Testing: Repair/Retrofit Building ID: Oc MNH03H C c Geographic Zone: WLA Northridge Tag: N Non-MRF Structural Damage? YES “Minor spalling of concrete @ expansion joints for subterranean parking. Corbel at joint provides vertical support for 14’ trib 2-way slab. Concrete spalled from corbel causing partial loss of support.” Non-Structural Damage? Life Safety related: YES “All common exits remained open and unobstructed; however, ... ovettumed filing cabinets, bookcases, cubicle partitions, etc. blocked hallwaysandcorridorsintenant Othec Design Code: LABC Year Designed: 1978 Year Built: 1979 ~6~~a11/steel s~d wallsout of plumb, numerous falling T-bar track and tiles, minor window cracking, HVAC cooling towers spring isolators broke.” ALSO: see LS-related damage regarding overturned furnishings. 1976 MRF Stories Above Ground: 3 MRF Stories Below Ground: O Ground Floor Area[sfj:7,000 Upper Floor Area [sfj: 7,000 Plan Irregularities? N Veftical Irregularities? N Column Fy [ksi]:36 Girder Fy [ksi]: 36 Floor Construction Type: W Web Connection Type: B Flange Weld Process: U Number of Frames in Each Direction: N-S NE-SW 2 E-W NW-SE 3 Notes: MRF ConnectionInspection/TestingScope and DamageSummary No of Inspected Floor-Frames 9 TotalNo of Corms in Inspected FF’s 52 No of Connections Inspected: No of Connections Tested: 32 o o/owl :0.0 Yo Damage Score :0.00 Number of Floor-Frames in each Damage Class for each inspected/tested Frame. A-43 NIST Survey of Steel MRF Buildings Affected by the NoRhndge Earthquake Friday, January 13, 1995 Survey Date: 9129194 Survey Form: new Pre Nridge Status: Status as of 9129194 Inspection/Testing: Repair/Retrofit OC Building ID: Oc C na MNH04 Geographic Zone: SO Northridge Tag: U NfloM,~~n~~uctural Damage? Non-Structural Damage? Life Safety related: YES “Minor ceiling tile displacement. Minor cracking of interior partitions.” Othec Design Code: UBC Year Designed: 1981 1981 Year Built: 1979 MRF Stories Above Ground: 6 MRF Stories Below Ground: O Ground Floor Area [sfi: 32,000 Upper Floor Area [sq: 32,000 Plan Irregularities? N Vefical irregularities? Column Fy [ksi]: 36 Girder Fy [ksi]: 36 Floor Construction Type: MCL Web Connection Type: B Flange Weld Process: SMAW Number of Frames in Each Direction: N-S 4 NE-SW E-W 4 NW-SE Notes: MRF Connection lnspection~esting Scope and Damage Summary Total No of Corms in Inspected FF’s: 54 31 31 NCIof Connections Inspected: No of Connections Tested: No of Inspected Floor-Frames: 12 Yawl : Damage Score :0.00 Number of Floor-Frames in each Damage Class for each inspected/tested Frame. 2 6 A2 : Xl NS NS NS 2 2 2 2 3 A-44 Friday, January 13, 1995 Survey Form: old Pre Nndge Status: NIST Survey of Steel MRF Buildings Affected by the Northridge Earthquake Suwey Date: 8/21/94 OC Status as of 8/21/94 Inspection/Testing: Repair/Retrofit Building ID: Oc C NS NYA539 Geographic Zone WI-I Northridge Tag: U Non-MRF Structural Damage? Non-Structural Damage? Life Safety related: Othec Design Code: LABC Year Designed: 1984 Year Built: 1985 1980 MRF Stories Above Ground: 3 MRF Stories Below Ground: O Ground Floor Area [sfl: Upper Floor Area [sfi: 28,000 Plan Irregularities? Y reentrant comer (L-shaped diaphragm) Vertical Irregularities? N Column Fy [ksi] 36 Girder Fy [ksi]: 36 Floor Construction Type: MC Web Connection Type B Flange Weld Process: U Number of Frames in Each Direction: NE-SW N-S 6 E-W 6 NW-SE Notes: MRFConnectionInspection/TestingScopeand DamageSummary No of Inspected Floor-Frames: 14 TotalNo of Corms in Inspected W’s: 54 No of Connections Inspected: No of Connections Tested: 33 33 Yowl :100.0 ‘?/0 Damage Score :.68 Number of Floor-Frames in each Damage Class for each inspeckdtested 34 34 34 T Y 20 E 2 20 20 A-45 Frame. NIST Survey of Steel MRF Buildings Affected by the Northridge Earthquake Friday, January 13, 1995 Survey Date: 8/17/94 Survey Form: old Pre Nridge Status: OC Status as of 8/17/94 Inspection/Testing: Repair/Retrofit NYA544 Building ID: (3C C NS Geographic Zone: WI-I Northridge Tag: U Nfl-MRF Structural Damage? Non-Structural Damage? Life Safety related: Other Design Code: I-ABC Year Designed: 1975 Year Built: 1976 Ground Floor Area [sfl: 25,600 Upper Floor Area [sfj: 25,600 MRF Stories Above Ground: 13 MRF Stories Below Ground: 1 Plan Irregularities? N Vertical Irregularities? N Column Fy [ksi]: 36 Girder Fy [ksi]: 36 Floor Construction Type: MC Web Connection Type: B Flange Weld Process: U Number of Frames in Each Dirti”on: N-S 2 NE-SW E-W 2 NW-SE Notes: MRF ConnectionInspection/TestingScope and DamageSummary TotalNo of Corms in inspected FF’s: 560 No of Inspected Floor-Frames: 56 No of Connections Inspected: No of Connections Tested: 545 545 ‘??OW1 :50.0 0/0 Damage Score :1.09 Number of Floor-Frames in each Damage Class for each inspected/tested Frame. 4 9 0 A-46 0 1 0 5 1 0 0 Friday, January 13, 1995 Survey Form: old Pre Nridge Status: NIST Suwey of Steel MRF Buildings Affected by the Nodhridge Earthquake Survey Date: 8/22/94 OC Status as of 8/22/94 Inspection/Testing: Repair/Retrofit Building ID: Oc C NS NYA550 Geographic Zone: SO Northridge Tag: U Non-MRF Structural Damage? Non-Structural Damage? Life Safety related: Othec Design Code: Year Designed: 1985 Year Built: 1985 MRF Stories Above Ground:6 MRF Stories Below Ground: O Ground Floor Area [sfJ:53,400 Upper Floor Area [sfJ: 21,000 Plan Irregularities? Y reentrant comer VefticalIrregularities? Column Fy [ksi]:36 Girder Fy [ksi]: 36 Floor Construction Type MCL Web Connection Type B Flange Weld Process: U Number of Frames in Each Direction: N-S 5 NE-SW NW-SE E-W 5 Notes: At floors 5-7(rf), 2 NS, 2 EW. Y mass& geom irreg at floor 4 setback. MRFConnectionInspection/TestingScopeand DamageSummary Total No of Corms in Inspected FF’s No of Connections Inspected: No of Connections Tested: 90 31 31 No of Inspected Floor-Frames Yowl :100.0 ‘A Damage Score :.13 Number of Flmr-Frames in each Damage Class for each inspectedltested Frame. A-47 15 NIST Survey of Steel MRF Buildings Affected by the Northridge Earthquake Friday, January 13, 1995 Survey Date: 8128/94 Survey Form: old Pre Nridge Status: Building ID: Oc C NS Status as of 8128194 Inspection/Testing: Repair/Retrofit OC IWA577 Geographic Zone: V&4 Northridge Tag: U Non-MRF Structural Damage? Non-Structural Damage? Life Safety related: CNhec Ground Firer Area [sfl 32,000 Upper Floor Area [sfl: 17,700 MRF Stones Above Ground: 14 MRF Stories Below Ground: O Design Code: Year Designed: 1980 1981 Year Built: Plan Irregularities? N Vertical Irregularities? ~e~a~kL geom irreg at floor 2 & 3 low roof Column Fy [ksi]:50 Girder Fy [ksi]: 36 Floor Construction Type: MCL Web Connection Type: B Flange Weld Process: U Number of Frames in Each Direction: N-S 6 NE-SW E-W 2 NW-SE Notes: At ground, including small frames under low roofs: 8 NS, 4 EW, 2 NWSE. MRF ConnectionInspection/TestingScopeand DamageSummary No of Inspected Floor-Frames: 20 TotalNo of Corms in Inspected FF’s: 94 No of Connections Inspected: No of Connections Tested: 29 29 O/owl :100.0 % Damage Score :.53 Number of Floor-Frames in each Damage Class for each inspected/tested Frame. Tw BW sjPz~cw A D E l-l NS NS NS 1 1 1 :; 1 27 1 : 0 0 A-48 0 0 0 0 0 0 0 1 Friday, January 13, 1995 Sutvey Form: new Pre Nridge Status: NIST Survey of Steel MRF Buildings Affected by the Northridge Earthquake Survey Date: 9/20/94 OC Status as of 9/20/94 Inspection/Testing: Repair/Retrofit Building ID: Oc C NS hWA591 Geographic Zone: WLA Northridge Tag: U Non6M~F Structural Damage? Non-Structural Damage? Life Safety related: U Othec u Design Code: LABC Year Designed: 1970 Year Built: 1970 MRF Stories Above Ground:28 MRF Stories Below Ground: 4 Ground Floor Area [sfj: 24,000 Upper Floor Area [sfJ: 24,000 Plan Irregularities? N Vefical Irregularities? Column Fy [ksi]: 36 Girder Fy [ksi]: 36 Floor Construction Type MCL Web Connection Type: W Flange Weld Process U Number of Frames in Each Direction: N-S O NE-SW E-W 2 NW-SE Notes: NS direction is Braced Frame Dual System MRFConnectionInspection/TestingScopeand DamageSummary No of Inspected Floor-Frames 16 TotalNo of Corms in Inspected FF’s 208 No of Connections Inspected: No of Connections Tested: 18 18 %owl :100.0 % Damage Score :.09 Number of Floor-Frames in each Damage Class for each inspected/tested Frame. A-49 — NIST Survey of Steel MRF Buildings Affected by the Northridge Earthquake Friday, January 13, 1995 Survey Date: 9/19194 Survey Form: new Pre Nridge Status: Status as of 9/19/94 Inspection/Testing: Repair/Retrofit Oc Building ID: Oc C NS NYA592 Geographic Zone: WLA Northridge Tag: U NonGM,~FStructural Damage? Non-Structural Damage? Life Safety related: U u Othec MRF Stories Above Ground:20 MRF Stories Below Ground: 1 Design Code: LABC Year Designed: 1969 1969 Year Built: Ground Floor Area [sfj: 24,300 Upper Floor Area [sfl: 24,300 Plan Irregularities? N Vertical Irregularities? N Column Fy [ksi]: 36 Girder Fy [ksi]: 36 Floor Construction Type: LC Web Connection Type: W Flange Weld Process: U Number of Frames in Each Direction: NE-SW N-S 2 NW-SE E-w 2 Notes: MRF ConnectionlnspectionlTestingScope and DamageSummary No of Inspected Floor-Frames: 10 Total No of Corms in Inspected FF’s: 124 %wl : 10 No of Connections Inspected: 10 Damage Score :0.00 No of Connections Tested: Number of Floor-Frames in each Damage Class for each inspected/tested Frame. 1 10 F g 5 9 A-50 ‘ Friday, January 13, 1995 NIST Sutvey of Steel MRF Buildings Affected by the Northridge Earthquake Sumey Form: old Survey Date: 8/17)94 Pre Nridge Status: OC Status as of 81W94 Inspection/Testing: Repair/Retrofit Building ID: Oc C c SOA Geographic Zone: SO Northridge Tag: Y Non-MRF Structural Damage? YES “Base plate anchors broke free from base plates. Large areas of spalled concrete around many column bases. One base shifted 3/4” north, another 3/6’’.” Non-Structural Damage? Life Safety related: YES Facade of Brick veneer cracked& broke away from anchorage,...falling hazard .... Other Design Code: LABC Year Designed: 1984 Year Built: 1985 YES Lots of broken glazing panels, cracked facade, stucco cracks@ elev mre, racked doors, ...ceiling panels... interior walls... sefflement of exterior slabs and walkways. 1980 MRF Stories Above Ground:4 MRF Stories Below Ground: O Ground Floor Area [sfl: 29,800 Upper Floor Area [sfi: 25,015 Plan Irregularities? Y reent comers Vertical Irregularities? N Column Fy [ksi]:36 Girder Fy [ksi]: 36 Floor Construction Type: MC Web Connection Type: B Flange Weld Process: U Number of Frames in Each Direction: N-S 4 NE-SW E-W 6 NW-SE Notes: MRF ConnectionInspection/TestingScopeand DamageSummary Total No of Corms in Inspected FF’s: No of Connections Inspected: No of Conned”ons Tested: 184 160 ’160 No of Inspected Floor-Frames: 22 %Wl : 0.0% Damage Score :1.95 Number of Floor-Frames in each Damage Class for each inspectedltested Frame. A-51 NIST Survey of Steel MRF Buildings Affected by the Northridge Earthquake Friday, Januaiy 13, 1995 Survey Date: 8/25/94 Survey Form: old Pre Nridge Status: Status aS of 5/27/94 Inspectioflesting: Repair/Retrofit OC Building ID: Oc C NS SOMI Geographic Zone: MW Northridge Tag: N Non-MRF Structural Damage? YES “PJoticableseparation of mid-floor stair landing from adjacent stair d~all.” Non-Structural Damage? Life Safety related: NO “None” YES “Some ceiling panels.” other Design Code: lABC Year Designed: 1986 Year Built: 1985 MRF Stories Above Ground:4 MRF Stories Below Ground: O Ground Floor Area [stl: 18,400 Upper Floor Area [sO: 18,400 Plan Irregularities? N Vertical Irregularities? N Column Fy [ksi]: 36 Girder Fy [ksi]: 36 Floor Construction Type: W Web Connection Type: B Flange Weld Process: U Number of Frames in Each Direction: N-S 3 NE-SW E-W 3 NW-SE Notes: MRF Connection lnspectionlTesting Scope and Damage Summary Total No of Corms in Inspected FF’s: 38 17 17 No of Connections Inspected: No of Connections Tested: No of Inspected Floor-Frames: 9 Yowl :100.0 Yo Damage Score :.33 Number of Floor-Frames in each Damage Class for each inspected/tested Frame. BG 2 2 2 24 17 22 30 ; 2 TC BC TW TT o 0 o 0 ; o 0 : 0 0 A-52 Friday, January 13, 1995 NIST Suwey of Steel MRF Buildings Affected by the Northridge Earthquake Sumey Form: new Pre Nridge Status: Survey Date: 9/23/94 OC Status as of 9/23/94 Inspection/Testing: Repair/Retrofit Building ID: Oc C NS VVEA Geographic Zone: UC No*ridge Tag: N Non-MRF Structural Damage? YES “CMU block@ elev shaft cracked& fell; steel bms pulled from wall; wood bms @ stairwell damaged.” Non-Structural Damage? Life Safety related: YES “Elev unusable; stairwell exit inhibited Other Design Code: UBC Year Designed :1979 Year Built: 1981 YES “isolated ceif’g tiles fell; tall cabinets (file) fell.” 1976 MRF Stories Above Ground:4 MRF Stones Below Ground: O Ground Floor Area [sfj: 7,000 Upper Floor Area [sfj: 18,000 Plafl Irregularities? Vertical Irregularities? Y mass irreg Column Fy [ksi]:36 Girder Fy [ksi]: 36 Floor Construction Type: W Web Connection Type: B Flange Weld Process: U Number of Frames in Each Direction: N-S 2 NE-SW NW-SE E-W 4 Notes: MRFConnectionInspection/TestingScope and DamageSummaty No of Inspected Floor-Frames: 24 TotalNo of Corms in Inspected FF’s: 48 No of Connections Inspected: No of Connections Tested: 48 48 Yowl :0.0 ?40 Damage Score :1.54 Number of Floor-Frames in each Damage Class for each inspectedltested Frame. A-53 NIST Survey of Steel MRF Buildings Affected by the Northridge Earthquake Friday, JanuaV 13,1995 Survey Form: old Survey Date: 9/6/94 Pre Nridge Status: OC Status as of 6/1/94 Inspection/Testing: Repair/Retrofit Building ID: Oc C c WJEf Geographic Zcme: WH Northridge Tag: N Non-MRF Structural Damage? YES”6 inch permanent lateral displacement in height of 18 stow building. Steel stair connd”ons broken. Mechanical room block walls broken at connections to steel floor framing. Marble panel anchorages in lobby damaged.” Non-Structural Damage? Life Safety related: YES “Elevators not operational. Fire and electrical systems temporarily out.” Othec Design Code: UBC Year Designed: Year Built: 1986 YES “Ceiling tiles displaced, drywall partitions cracked, overturned shelves, etc.” 1985 Ground Floor Area [sq: 19,200 Upper Floor Area [sfl: 19,200 MRF Stories Above Ground: 18 MRF Stories Below Ground: 1 Plan Irregularities? N Vertical Irregularities? N Column Fy [ksil: 50 Girder Fy [ksi] 36 Floor Construction Type: MC Web Connection Type: B Flange Weld Process: FCAW Number of Frames in Each Direction: N-S 2 NE-SW E-W 2 NW-SE Notes: MIRFConnection [nspectionflesting Scope and Damage Summary Total No of Corms in Inspected FF’s: No of Connections Inspected: No of Connections Tested: 272 272 ‘??OW1:0.0 41 Damag~Score :.46 No of Inspected Floor-Frames: 68 Yo Number of Floor-Frames in each Damage Class for each inspectedltested Frame. A-54 Appendix B: Survey Forms B-l SURVEY OF STEEL IVIRF BUILDINGS AFFECTED BY THE JANUARY NORTHRIDGE EARTHQUAKE Suiiding Nanm/iD: survey Engc Firm: 1994 Or@ Date: Rem Daw Page: INSTRUCTIONS T(3 SURVEY ENGINEERS Complete survey form for each structurally distinct MRF building. Report all inspected and/or tested conditions, whether damaged or undamaged. :: Do not leave blanks. Use “U”, “NA”, or dashes “-” where necessary. See abbreviations. 3. Please give the street address in Section L If confidential, this information will not be 4. released to database users. If address or building name is to be kept confidential, use an appropriate unique code for “Building Name/ID”at the top of each page. ABBREVIATIONS General N No. None Not Appiicabla NA Other o u Y Unknown Yes PD MRF HAZ UT VI Building Use Apartment House A Condominiums c Data/Computing Center D Emergency (fire, ambulance, etc) E Hospital/Clinic H Hospital w/ OSHPD approval HO Hotel/Motel HL Laboratory/Rasearch 1. Manufacturing/Industry M Lataral Load Resisting Systems OMRF Ordinary MRF SMRF Special MRF DMRF Ductile MRF (pre-1988 UBC) Concentrically Braced Frame CBF Eccentrically Braced Frame EEIF Dual System: MRF + shear walls DSW DCBF Dual System: MRF + CBF DEBF Dual System: MRF + EBF OF P Office Parking Retail School School w/ DSA approval Theatre/Church/Assembly Utility Warehouse R s SD T u w Floor Construction Types w Wood diaphragm WI wood or metal joists M Bare metal deck w/ steel beams or joists MC Metal deck w/ normal vvt concrete fill MCL Metal deck w/ lightweight concrete fill P Precast concrete planks WI topping slab Weld Processes FCAW Flux Cored Arc Weld Shielded Metal Arc Weld SMAW Submerged Arc Weld SAW GMAW DEFIN~lONS Building Gas Metal Arc Weld Set of diaphragms laterally supported by the same set of frames or structurally separated from other diaphragms by sejsmic joints. Moment-resisting frame. System of moment-connected beams and columns generally in a single vertical plane. One frame has tha sama nama/designation at each floor. Intersection of one frame beam with one frame column, generally comprising a IOP flange connection, a bottom flange connation, and a web connection. A typical joint with a continuous column and beams on both sides constitutes two connections. The set of connections in one MRF at one floor level. MRF Connection Floor-Frame &dxww@2ngbm. Principal Direction Moment-Resisting Frame Heat-Affected Zone Ultrasonic Testing Visual Inspection doc B-2 SURVEY OF STEEL MRF BUILDINGS AFFECTED BY THE JANUARY 1994 NORTHRIDGE EARTHQUAKE Building Name/ID: Survey Engc Firm: Orig Date: Revn Date: Page SECTION 1: PROCEDURAL Person(s) Completing Survey (Survey Engineer) _ Agency/Firm Firm Address Telephone Confidential? Building Location (Y/N) Street Number Street Name City Zip Code Cross Street(s) Neighborhood/District Note: for major renovations or additions at the same address, please distinguish original frames from added or strengthened frames and complete the applicable sections of a separate form. Indicate items available to the survey engineer or used as the basis of survey responses: Available Architectural Used drawings Structural design drawings Structural as-built drawings Original structural talcs Geotech/soil report Site specific design spectrum Steel/Welding specifications Fabrication/Erection drawings Post-Northridge visual insp’n data Post-Northridge testing data Post-NoRhridge talcs/analysis results Photographs of inspected conditions Weld or steel samples removed Other B-3 — SURVEY OF STEEL lVIRF BUILDINGS Building Name/ID: Firm: Survey Engc AFFECTED BY THE JANUARY NORTHRIDGE EARTHQUAKE 1994 Orig Date: Revn Date: Page: SECTION !1:BUILDING HISTORY Year Designed Year Constructed Building Use (see Abbrev.): Principal Other? Secondary Other? Is the building owner a government Pre-Northridge or non-profit agency? building status (Occupied, Post-Northridge Under Construction, Vacant, Team Visual Insp Engr/Firm Testing Lab Repair/Retrofit Engr Current building status (Occupied, Visual inspection Complete, Testing Complete, Repair/Rehabilitation Repair/Rehab Under Construction, Vacant, etc.) In Progress, or Not Started (C, 1P, NS) In Progress, or Not Started Design Complete, Construction Complete, In Progress, or Not Started In Progress, or Not Started Additional description of current building status Date of above status information B-4 etc.) SURVEY OF STEEL MRF BUILDINGS AFFECTED’BY THE JANUARY 1994 Wilding NamailD: Survey Engc Firm: Orig Data NORTHRIDGE EARTHQUAKE Revn Dete: Page: SECTION Ill: NORTHRIDGE EARTHQUAKE PERFORMANCE Was the building tagged after Northridge (Unknown, None, Red, Yellow, Green)? If building was retagged or had its tag status changed in any way, please explain: Describe structural damage other than in MRF connections (consider permanent Describe non-structural lateral set, if any): damage (consider especially falling hazards and loss of egress): Describe the impact of damage on users (e.g., known injuries? voluntary evacuation? downtime?): business , Classify the distribution of structural damage (including MRF connection damage) as None, Isolated, or Widespread: Classify the impact of structural damage (including MRF connection damage) on the building’s overall life safety as None, Minimal, or Substantial: Classify potential required repairs of all damage as None, Cosmetic (non-structural (repairable without substantial demolition) ~or Heavy: only), Moderate B-5 ~, . I I SURVEY OF STEEL MRF BUILDINGS AFFECTED BY THE JANUARY 1994 I Building NameflD: Firm: Survey Engc I NORTHRIDGE EARTHQUAKE Orig Dete: Page: Revn Date: SECTION IV: BUILDING DESCRIPTION Total # of stories above ground: #of steel MRF stories above ground: Total # of stories below ground: # of steel MRF stories below ground: Maximum roof height above ground: Approximate Approximate footprint area: Typical floor construction typical floor area: (see Abbreviations): Describe the Iataral load-resisting system in each Principal Direction (see Abbreviations): Note: If building’s frames are in two directions only, ignore PD3 and PD4. PD 1 PD4 PD3 PD2 Compass Direction Lateral System Which (if any) vertical irregularities per 1991 Which (if any) plan irregularities per 1991 UBC Table 23-M appear to be present in the building? U13CTable 23-N appear to be present in the building? Design Code & year Typical girder F, (ksi) Typical column FY (ksi) Typical girders expected to act composite with deck? Typical girder web connections Girder flange weld process Describe welded only (W), bolted only (B), or welded & bolted (WB)? Field or Shop? (see Abbreviations): V table. Add sheets es necessary. Only inspected or tested con-ditions but descriptions of member sizes, number of bays, etc. in uninspected frames are each MRF in Section need be repotied, also appreciated. B-6 SURVEY OF STEEL MRF BUILDINGS AFFECTED BY THE JANUARY 1994 NORTHRIDGE EARTHQUAKE Suilding Name/ID: Survey Engr: Firnu Orig Date: RevnDate: Page: SECTION V: DAMAGE DESCRIPTION 1. 2. 3. Respond to the questions on this and the next page. Assign a name to each MRF. A given frame should have the same name at each floor. Complete one copy of the table below for each inspected MRF, whether damagedor not. 4. Show the MRF locationsand nameson a plansketchin SectionVll below. Note: Generally,each line of each Section V table will describe one inspected floor-frame. However, one line can be used for sevaral identical floors. Frames with mora than seven non-identical inspected floor levels will require more than one page. As an alternate to completing the tables, provide Section Vlll frame elevations for each frame, showing member sizes, extent of inspectionltesting, and damage type according to the reference schedule of damage types below. Describe the type and extent of $@cal Vkual visual inspection and_ testing (y/n/u): Testing: Inspection: fireproofing removed from beam ultrasonic fireproofing removed from COI flange magnetic particle fireproofing removed from panel zone dye penetrant steel cleaned weld sample taken backup bars removed for weld Vi/UT bm/col sample taken slab removed for top flange access plumbness survey window wall removed for far side access at perimeter frames inspected? beam top flange tested? beam bottom flange column flange full width of beam/column shear connection flange inspected panel zone inspected Basis for selecting locations to Vi/UT (e.g. cost, access, analysis, random): Describe inspection or testing criteria/procedures Describe any constraints on typical VVtesting (e.g. AWS D1.1 ): (e.g. at toP flanges and perimeter frames): B-7 SURVEY OF STEEL MRF BUILDINGS AFFECTED BY THE JANUARY NORTHRIDGE EARTHQUAKE Building Name/ID: Suwey Engc Firm: 1994 Orig Date: Revn Date: Page: SECTION V continued Describe any observed evidence of poor workmanship (e.g. use of end dams, small cope holes): Describe any observed deviations from approved drawings or specifications. Is there reason to think that poor workmanship or deviations contributed to damage? Explain: Of all the weld damage indicated in the floor-frame tables below, estimate the percentage that is UTdatected incipient root cracks only (type Wfl ) or minor discontinuities that may have existed preearthquake: if Column Web damage (class CW) is indicated for any of the floor-frames in the tables below, describe more completely the nature and location of such damage (or illustrate in Section Vi below): * SURVEY OF STEEL MRF BUILDINGS AFFECTED BY THE JANUARY 1994 NORTHRIDGE EARTHQUAKE - -D ‘orig Dw. .—* Rmm Dam SECTION V continuedDescribeeach inapactad floor-frame. See *don B-9 mm V imtiom above. I SURVEY OF STEEL N’IRF BUILDINGS AFFECTED BY THE JANUARY NORTHRIDGE EARTHQUAKE &kiirw Name/ID: %rwy Engr: 1994 Finn: Date: Orig Revn Date: Pege: SECTION V continued REFERENCE SCHEDU!.r CIF DAMAGE TYPES (See Reference Details below for pictorial description.) G GIRDER DAM.z = E G1 buckled flange yielded flange G2 flange tearout near weld G3 flange crack outside HAZ G4 CF COLUMN FLANGE DAMAGE incipient flange crack (detected by UT) cl C2 complete flange tearout or divot full or partial cross-flange crack in HAZ C3 full or partial cross-flange crack outside HAZ C4 Iamellar flange tearing C5 w FL4NGE WELD DAMAGE incipient crack, especially at weld root (detected by Ull WI W2 crack through weld metal, full or partial width of flange W3 fracture at girder interface fracture at column interface W4 s SHEAR CONNECTION DAMAGE column to web or column to shear tab weld crack S1 S2 web to shear tab supplemental weld crack web or shear tab crack, especially through bolt holes S3 web or shear tab deformation, especially.. at holes.. S4 loose, damaged, or missing bolts; faying surfaces out of contact S5 p: PANEL ZONE DAMAGE P1 P2 P3 P4 Cw fracture, buckle, or yield of continuity plate crack in continuity plate welds buckle, yield, or ductile deformation of doubler plate or column web crack in doubler plate welds COLUMN WEB DAMAGE P5 partial depth crack in column web or doubler plate (extension of C3 or C4) P6 full or near full depth crack in column web or doubler plate B-10 - SURVEY OF BuildingNama/lD: STEEL MRF BUILDINGS AFFECTED BY THE JANUARY 1994 Firm: Survay G-w Orig Date: NORTHRIDGE EARTHQUAKE Page: Revn Date: SECTIONV continued REFERENCE DETAIL(See ReferenceScheduleabove for damage type descriptions.) %’ & ● S5 S4 I L ---@ ~A --@ O* I I I ~1 I S3 I I I I I I 10 G4 * REFERENCE NOTE: SEE DETAIL REFERENCE MRF JOINT SCHEDULE B-1 1 DAMAGE FOR IYPES DESCRIPTION SURVEY OF STEEL MRF BUILDINGS AFFECTED BY THE JANUARY NORTHRIDGE EARTHQUAKE Building Name/ID: Firm: Survey Engc 1994 Orig Date: Page: Revn Date: SECTION V continued REFERENCE DETAIL (See Reference Schedule above for damage type descriptions.) REFERENCE “ NOTE: SEE DETAIL: REFERENCE MRF SCHEDULE B-12 DAMAGE FOR TYPES DESCRIPTION SURVEY OF STEEL MRF BUILDINGS AFFECTED BY THE JANUARY 1994 NORTI-IRIDGE EARTHQUAKE Building Name/ID: Firm: Survey Engc Orig Dete: Revn Dete: Page: SECTION W: SPECIFIC DAMAGE DETAILS Instructions to Survey Engineer: Complete details shown for one or two specific conditions per building. Show damage and identify by type according to Reference Schedule above. SAY sPAN(Ft) BAY SPAN(Ft) — + I Fy(Ksi): _ cob r — _ Fy(Ksi): _ I \ 4PHRAGM INSTRUCTION: — COMPOSITE ? — /- GIROER” .— STORYHT. ABOVE (n): . — J Fy(Ksi): _ w I - i y’ / r A t-- —— I STORY HT BELOW (Ft): — < WELOEO WEB lo 10 <‘ I v 1° PL k . I 1° 10 i ..- I byw&AR CONT. PL t— BOLT WPE: — J ~ DOUBLER PL k — JOINT DAMAGE TEMPLATE DETAIL NOTES: FIELD OR SHOP? :— I II BOLT Ok_ STRONG AXIS COL. ELEV. 1. U.N.O., AS-BUILT DIMENSIONS AND SIZES SHOWN ON ONE SIDE TOP OR BOITOM ARE ~. 2. 3. OATE VISUALLY INSPECTED: _ FLOOR: — . TO BOTH SIOES, TOP AND BOTTOM. SEE PLAN DEfAILS FOR ADDITIONALlNFORMAnON. REFER To OAMAGElYPE 013AIL/SCHEDULE FOR EXPLANATIONOF OAMAGEFIAGS. DATE TESTED: _ FRAME DESIGNAmON (PER SEPARATE PM SKETCH) : JOIF4TLOCATION IN FRAME (DEscRIBE OR REFER TO SEPARATE ELEVATION) : AT THIS FLOOR ANO FRAME, DAMAGE SHOWN IS — MOST SIMIIAR JOINTS ON THIS FLOOR w — lwlu NO DAMAGE, _ B-13 _ WORST CASE LESS DAMAGE, _ SIMIIAR DAMAGE SURVEY OF STEEL NIRF BUILDINGS AFFECTED BY THE JANUARY 1994 NORTHRIDGE EARTHQUAKE Wilding Name/ID: Firm: Survey Engr: Orig Date: Revn Date: SECTION W: SPECIFIC DAMAGE Page: DETAILS Instructions to Survey Engineer: Complete details shown for one or two specific conditions per building. Show damage and identify by type according to Reference Schedule above. CONT. PL / WELO, / I BACKING aAR / t : 1 # I I I, c:=====:: I * I GIRDER WEB \ : k: :=-==:==3 , 1 8 1 & I I : I : a I H Y I I : # I I , 1 : : I I I 1 I , 1 i I I I --l I 1 o JOINT DAMAGE <> ) BOTTOM FLANGE TEMPLATE DETAIL - STRONG AXIS PLAN NOTES: :: SEE COLUMN ELEVATION FOR MEMBER SIZES, DIMENSIONS, AND ADDITIONAL INFORMATION. REFER TO OAMAGETYPE DETAiL/SCHEDULE FOR Explanation OF DAMAGE FLAGS. FLOOR: _ FRAME DESIGNAnON (PER SEPARATE PIAN SKDCH) B-14 : SURVEY OF STEEL MRF BUILDINGS AFFECTED BY THE JANUARY 1994 NORTHRIDGE EARTHQUAKE Building Name/ID: Fim StJwey Engc Orig Date: Revn Date: SECTION Vl: SPECIFIC DAMAGE Page: DETAILS details shown for one or two specific conditions per building, Show damage and identify by type eccording to Reference Schedule above. instructions to Survey Engineer: Complete BAY SPAN(Ft) BAY sPAN(Ft) — _ [ %MH$TION + .— GIRDER _ ~NONFIF ONE-SIDED) Fy(Ksi): — \ GIROER” .— STORY HT. ABOVE (Ft): A — —— —. .— —— u 1STORY HT BELOW (Ft): Fy(Ksi): — II 7F ‘ I _ 10 10 I <‘ I 10 I v 1° 10 PL t: . I I —— —— + I L 10 —— —— WELD PROCESS A FIELD 1 #BOLTS:— OR SHOP? I BOLT OIA — aOLT TYPE: — JOINT DAMAGE TEMPIATE DETAIL - WEAK AXIS COL. ELEV. w NOTES: 1. 2. 3. U.N.O., AS-BUILT DIMENSIONS ANO SJZES SHOWN Oti ONE SIDE TOP OR BOTIOM ARE m. TO BOTH SIOES, TOP AND BOllOM. SEE PLAN OETAIL FOR ADDITIONALINFORMATION. REFER TO OAMAGETYPE O~AIL/SCHEDULE FOR EXPU1’JAnON OF OAMAGE FLAGS. DATE VISUAUY INSPECTED: — FLOOR: . OATE TESTEO: — FRAME DESIGNATION (PER SEPARATE PIAN SKflCH) JOINT LOWTION IN FRAME (Dt3CRIBE OR REFER TO sEpARATE swAnoN) AT THIS FLOOR ANO FRAME, OAMAGE SHOWN 6 MOST SIMIUJ? JOINTS ON THIS FLOOR HAD _ — TYPICAL, NO DAMAGE, _ _ ; : WORST CASE LESS DAMAGE, _ SIMILAR OAMAGE SURVEY OF STEEL NIRF BUILDINGS AFFECTED BY THE JANUARY 1994 NORTHRIDGE EARTHQUAKE Building Name/ID: Survey Engc Orig Date: Page: Revn Date: SECTION Vi: SPECIFIC DAMAGE DETAILS shown for one or two specific conditions per building. Show damage and identify by type according to Reference Schedule above. Instructions to Survey Engineer: Complete details WELO BAR / , \p~ 1 i 1, I : 1 GIRDER WEB ------------- -- a! : : 1 1 I (> : I t 1 I I t I o DAMAGE I t I t I I 8 I : I 1 o JOINT I t 1 : 1 1 1 I 1 I I 1 I, c--------: -------- (2 : s TOP FLANGE ROTTOM FIANGE TEMPI_ATE DETAIL - WEAK AXIS pUN NOTES: j: SEE COLUMN ELEVAnON FOR MEMBER SIZES, DIMENSIONS, AND AODlnONAL INFORMATION. REFER TO DAMAGE NPE D~AIL/SCHEDULE FOR EXPLANATIONOF DAMAGE FLAGS. FLOOR: — FRAME OESIGNATlON(PER SEPARAE pm B-16 SKErCH) : SURVEY OF STEEL MRF BUILDINGS AFFECTED BY THE JANUARY 1994 NORTHRIDGE EARTHQUAKE Building NamellD: Survey Engc Firm: Orig Date: Revn Date: Page: SECTION Vii: PLAN SKHCH Instructions to Survey Engineer: Provide a plan sketch of the building showing compass direction, Principal Directions, basic floor plate dimensions, relative locations of frames, and frame names/designations as tabulated above in Section V. B-17 SURVEY OF STEEL MRF BUILDINGS AFFECTED BY THE JANUARY 1994 NORTHRIDGE EARTHQUAKE Suilding Name/ID: Survay Engc Firm: Orig Date: Revn Date: Page: (Optional) Instructions to Survey Engineer: Provide frame elevations showing frame name/designation, SECTION VIII: FRAME ELEVATIONS Principal Direction, basic bay and story dimensions, and indications of inspected and damaged connections. B-18 & SURVEY OF STEEL MRF BUILDINGS DAMAGED BY THE NORTHRIDGE EARTHQUAKE, JANUARY, OF GI OSSARY Wlif.fins &gin. r%m oat% 1994 Page TFRMs USQ A- Apartment House @ndominiums Emergency (police, fire ambulance. Hospital/Clinic Hospital wKXHPD compliance Hotel Manufacturing/Industry Office Parking c- EHHOHL!4: P- R s Retaif School Schoolw/DSA compliance TheaterlChurch/Public Assembly Utility Warehouse SD T etc.) Other Plan shaDe~ uDO . %’% . . Dsw DEBF DCBF . . . Foundation sF - G- MPPc - PF- Eccentrically Braced Frame Concentrically Braced Frame Special MRF Ordinary MRF Dual System SMRF with shear walls Dual System SMRF with E13F Dual System SMRF with CBF Floor Constructon TVIMW spread Wooddiaphragm w- footings MContinuous or combined footings Mc Mat McL Piles or caissons with individual pile caps Piles or caissons with combined or continuous pile cap P - Other - FcAw SMAW SAw GMAw o . . . Fhdjy Pinned base FKed base or cxmtinuous into stiff wall element Cantinuous into basement frame columns c- TVD e q Individual - Column Lateral ~oad Resistlna s~stems EBF C8F lkr W-Shaped Doughnut (center cotmyard) Other Flux-Cored Arc Weld Shielded Metal-Arc Weld Submerged-Arc Weld Gas metal-Arc Weld Other B-19 with wood or metal floor joists Bare metal deck with steel beams or floor joists Metal deck with normaf weight concrete fill Metal deck with lightweight concrete fill Precast concrete planks with topping slab Descriie SURVEY 13AKIIAGED BY THE NORTHR!DGE JANUARY. 1994 INSTRUCTIONS; 1) Completeentire surveyform for 2) auildrig OF STEEL IW?F BUiLDINGS EARTHQUAKE. -~ firm Oata Page original building. 3) For major renovations or addtiions, complete the applicable portions of a separate survey form. Please respond to all items. Where necessary, use “W (for unknown) or dashes ‘—” to show that information is not available. 4) Do not leave blanks without explanation. Where not specified, the following abbreviated responses maybe used Y = yes, N = no, Us Unknown, or N/As not applicable. SECTION k Procedural 1) 2) Date of original survey 3) Person Completing Survey 4) Agency/Firm 5) 6) m’m’m’”’ Date of thisrevisionto survey J I I 102 1 I I I I I I I I I I 104 I . Phone Number * . 105 I Building Looation Number I I I I 106 I I I 10s 107 Street CQ 109 Zip Code Cross Street I I I I I I I I I I Is this survey for the original building (0), for a pre-Northridge renovation (R), or an addtiion (A)? Enter O, R, (Note: For each major renovation/addition, complete the applicable portions of a separate survey form) 8) Basis of survey responses (enter Y, N or N/A to each): 113 114 Structural Drawings Fabrioatior@’ection Firsthand Drawings post-Northrige 115 visual inspection Post-Northridge visual inspection report by other engineer 116 Post-Northridge test report 117 !’ B-20 %4 RmidM 4. W lAW K. MarAraUiw@ty 110 111 Vicinity/Neighborhood 7) 103 d SO@JwnCal!hnb or A. U112 SURVEY DAMAGED OF STEEL MRF BUILDINGS BY THE NORTHRIDGE JANUARY. auiknng: -. EARTHQUAKE= 1994 % oate: auwllglok Page l~jctv (bri!mmd.alq) ; CTION 11: Buildina fiistom rErri20f 1) Year Designed 2) Year Constructed 3) Yeara of Major Renovations/Additions 4) 8uilding Use: (Enter the ap ro rfate choioe for eaoh from the glossary of terms, building use section) ~= ~~~(Note: For each major renovation/addition, complete the applicable portions of a separate survey form) Prfnoipal Use 204 Secondary Use If other, please describe If other, please deeoribe Tertiary Use If other, please describe B: 5) Is this primarily a government building? (Enter Y or N) 6) Pre. NorhrkfoeTeam c1 207 Engineer of Raoord: 206 ArchitecL 209 Source of Steel (i.e. US, Japan, etc.) ~ Steel Fabricator 2fo Steel Erectoc 211 Permit Granting Authority 212 Post . NWhdcfae Tea Inspecting Engineec lnspectio~esting . I 213 214 Lab 215 Repair/Retrofit Engineec 216 Repair/Retrofii General Contractor Permit Granting Authority B) Building status before Northridge earthquake: OC = occupied, 9) W = limited occupancy, L I V = vacated, 217 I I J218 UC = under construction, O = other Current Building Status Enter OC for occupied, Lfvt for limited ocoupanoy, or V for vacated: Is an investigation or testing in progress (1P), completed fe the repair or rehabilitation design in progress (1P), oompleted (C), or not yet started (NS)? Is the repair or rehabilitation construction in progress (1P), completed (C), or not yet statted (NS)? 221 B: m Additional description of building status: o) Date of above status repoti 219 (C), or not yet started (NS)? Cnlm’m=’ B-21 SURVEY OF STEEL Mt7F BUILDINGS DAMAGED BY THE NORTI+RIDGE JANUARY. 1994 auikri~ EARTHQUAKES *neec mm Oate 1) Did the building sustain non-stmtural damage h previousearth 1971 San Fernando Earthquake uakes? (Y or N) 301 302 1987 Whittier Narrows Earthquake 1992 Big Bear Earthquake 2) Page B. or N) Did the building sustain structural damage in previous earthquakes? 1971 San Fernando Earthquake 1987 Whittier Narrows EaRhquake 305 1992 Big Bear Earthquake a: 3) Was any previousdamage repairedpriorto the Northrigde Earthquake? 4) Was the building tagged after the Northridge Earthquake? (R=red, Y=yellow, G=green, N=none) 5) Was the building voluntarily evacuated? 6) Describe any Northndge anchor bolts, diagonal [307 l“_lsrxr (Y or N) structural damage braces, I (Y, N, or N/A)’ obsewed (other than steel MRF joints discussed below). Consider base plates, members, shear walls, diaphragms, etc. non-MRF 310 7) Classifystructural damage (including MRF joints) in terms of its distribution as None (N), Isolated (1)or Widespread (WJ 8) Classify structural damage (including MRF joints) in terms of its impact on the building’s overall life-safety 0 c1 311 312 as None (N), Minimai (M), or Substantial (S). 9) as None (N), Cosmetic Classify overeil damage (including MRF joints) in terms of repairabiiii D 313 (non-structural only) (C), Moderate (repairable without substantial demolition) (M), or Heavy (H). 10) Was ther permanent iateral defection? (Y or N) 0314 if Yes, please describe 11) Was there apparent pounding? (Y or N) 12) Was there apparent foundation faiiure? Was there apparent liquefaction? Wes there apparent differential Was there apparent settlement? 0315 0316 (Y or N) (Y or N) 317 ground movement? (Y or N) (Y or P$ 318 319 H 13) List/describe any Northridge life-safety related non-structural damage. Consider blocked exits (inofuding stairs and elevators), faliin9 hazards over exits and sidewalks, hazardous 14) List/describe equipment any other Northridge faiiures (inciuding material non-structural spiis, loss of fire protection systems, etc; damage. HVAC/Eiectrfcai/Plumbing), consider overturned exterior ciadding, parapets, glazing, p~~ons, sheiving, B-2! /$4 ~ 4, W1lM. K. MwuwUdwnsky 01%J!JWMCdih?4@ etc.: 320 ceilings, lights, S21 SURVEY DAMAGED OF STEEL MRF BUILDINGS BY THE NORTHRIDGE Suw Enginetm Film Oate: EARTHQUAKE. ~4 Suilding10* _ Iv : Build ina Descrintion and Des ian F&~oN 1) 3) Total #of stories above ground: 4101 Total #of storfes below ground m 4102 Maximum ~feet roof height above ground Total Length 5) Total Width m~::; Total ground floor enclosed area Q B) 2) #of Steel MRF stories above ground #of Steel MRF stories below ground Sq. ft. 410s Sq. ft. 4109 Plan shape of building at ground flooc (See glossary of terms, for choices) describa II other, q Plan shape of buiiding at typical MRF floon (See glossary of terms, for choices) M 4111 II orher, desaii. o) Design Code Used (U= UBC, T = Titfe 24,0 1) Year of Design Code = Other UBC ConstrurMon Type (1,11,Ill, IV, or w 3) ASO or LRFD for steel MRF? 4) Wss a dynamic analysis used for the design of the building? 5) Describe 6) Code Static Design additional ) design cnleria (MPE, d~ m~“’ (Y or N) cl” ml limits, etc.), if any. EE3= Importance Factor, 1,used Soil Factor, S, used Principal Direction 1 (PDl~ Compass direction for Principal Direction 1 (N-S, NE-SW, etc.): Steel Letersi Load Resisting System (See giossary of terms for choices): K (pre-1988): Coefficient RW Base Shear Coefficient VIW (if avsilabie] Principal Direction 2 (PD2): Compass direction for Principai Direction 2 (N-S, NE-SW, etc.): 4010 Steei Lateral Load Resisting System (See glossary of terms for choices): 421f Coefficient K (pre-1988): 4312 Coefficient Rw. Fundamental Period T used for design, in seconds 4s13 Baee 4314 Shear Coefficient WV/ (if available): x B-23 ~4. 73$ 4307 - Fundamental Perfod T used for design, in seconds: I nd~l ~“ 2) 18) rMlm 41M l,l, Totaf building floor area (not inctuding roof area): Coefficient m 41U3 4’” 4110 7) ibrb9mmilnaciwfJ Ground Floor Dimensions Approximate 4) 6) Crr13 K.Matk#wurhmny Olsa#mnlcalilOlnb 4315 euadiq IZnguteec SURVEY OF STEEL MRF BUILDINGS DAMAGED BY THE NORTHRIDGE JANUARY, 1994 EARTHQUAKE. h oat= Page {Section IV Co ntinued] 19) Potential Structural Imegularities (indicate Y, N, or WA): PD1 Discontinuous ColumnsWeak PD2 4407 4’401 Story soft story Plan setbacks!out-of-plane Diaphragm Torsional Fieentrant 20) offsets 4410 Discontinuity 4411 Irregularity Comers 4412 B’ Ii Grade of Steel Specified: (36, 50, or sire) Frame Columns Frame Girders Diagonal Braces 4501 B. 4502 21) Ground level column fixity, P, F or C (See glossary of terms for description): D- 22) Foundation Types (See glossary of terms for choices): 04= Describe the following non-structural components. Consider materials, vertical suppo~ lateral support, abilii to accommodate interstory drifts, etc. 23) Exterior Cladding/Glazing/Curtain WallsJParspets 450e 24) Interior Partitions, including stair and shaft enclosures: 4s07 25) Ceilings 4504 B-24 6/14 f?wkh 4. WI liE4 K. tiaM4w&iY d SMIUWM CFMmia SURVEY DAMAGED euiidhg: OF STEEL MRF BUILDINGS BY THE NORTHRIDGE Engmwwc %111: Oww EARTHC?UAKE% allikfing10 * Pwge: Crnaf ‘~q ;omplete tiere 1 set of Section V data for each floor with inspected connections, i.e. provide sets 1, 2, 3, etc., the floor number becomes the last digit of the database entry number below) Floor Numbec m“”” Story height above: ~feet 510ZX Story height belowc Mfeet “m floor Area EEnz=i’qfeet Approximate Floor Dimensions: Length I Width I “ax feet 5105X feet 51MX Does floor have disoontinuities or reentrant comers as noted above? Total numberof MRFs intersectingth~ floor in Prinapal Direction Total number of MRF’s intersecting Direction 2 1: B-25 C4SIMM4, W11MKklUWxwUInwdW d SUWIMI Cd#m’$B ~15~ozx If other, describe Floor Construction (See glossary of terms for ohoioes): T[5KWX this floor in Prinapal (Y or N) Cnsf@’ m5f’@f .==-* Y auiiding SURVEY OF STEEL MRF t3UlLDlNGS DAMAGED BY THE NORTHRIDGE JANUARY. 1994 EARTHQUAKE Engineer firm Oate Building Fage ID& lzIIz~’ @’-w* ~ECTION V: Continued Complete for each inspected frame at this floor, i.e. provide data sets a, b, etc. for floors 1,2, etc. the following information FloorNumber,X (i.e. 1,2,3, etc.)= Frame Number,x&e. &B, C, etc.)= n n 10) Principal Direction: 11) Total Frame Length ~ “et ~ 12) Length of diaphragm openings adjacent to frame ~ ‘eet -’ 13) Column Strong or Weak MIS (S or W): c1 14) %x Columns (Y or N): n m=’” 1!5) Number of Bays 5204XX S205Xx m- 16) Total number of beam-column connection.% L-lJ~ 17) Total number of connections visually inspected: r-( 18) Total number of connections tested: 19) Minimum bay wicftix m m==’ 20) Typical bay width: EIzIa 21) Maximum bay w“dtfx 22) Typical end column section: 23) Typical interior column section 24) Typical girder section: 25) Is the girder expected to act composite with the deck? (Y or N) ‘ Complete the following for a typical inspected Connetilon l=lfi “et - ‘eet ‘“ us30exx at this frame and ffocm S401xx 26) Top flange Complete (C) or Partial (P) penetration weld? n 27) Was the top flange backing n~ 28) Bottomflange Complete (C) or Partial (P) penetration weld? u~ 29) Was the bottom flange backing bar left in place? (Y or N) c1 5404XX 30) Wwe run-off dams used? El 540SXX 31) What weld process was used? (See glossaty of terms for choices) n 5-$(XXX If other, describe: 32) Was the connection of the girder web to the shear tab welded only (W), bolted only (B), or welded & bolted f,WB)?l~[~W bar left in place? (Y or N) (Y or N) t B-26 W14 Revi6m4. WltM K.h4advtinhmslIv c450uthwn Califcmia I 1 SURVEY OF STEEL lklRF BUILDING~ DAMAGED BY THE NORTHRIDGE EARTHQUAKE, JANUARY, Fw — ~oTAL*o~ ;ECTION V: *& ntinued CO )amage Description t%c Dsra 1994 f%wM& ,—, Ut@6~TIOIW _ @ml&”cmdr For this ffoor and fmme, indi~te ltwELTE the total #Of connections Psw — auwlglD8 Ci333, = P _ showing each damage type. Ind”ate II for conditions not inspected. Indicate NA where appropriate. 34) Damage Type #of Inspected Top Description (see detail) #of Connections Damaged Girder G1 Buckled flange Damage G2 Ytelded flange G3 Flange tear-out G4 Flange crack outside heat-affected zone (HAZ) H 5502XX S503xx 5SOS%X 5507XX B S&#xx S50exx 5SO!?XX Column Cl Incipient flange crack Flange C2 Flange tear-out 55f2xx Damage C3 Full or partiat cross-flange crack h: H&! 5WXX C4 Full or partial CrOSS flange crack outside HAZ C5 hmeilar WI Incipient weld crack Weld W2 Full or partial crack through weld metal Damage W< Fracture at girder interface W4 Fracture at culumn interface Shear SI Weld crack at column (welded web only) Connection S2 Weld crack at shear tab Damage S3 Crack in girder web or shear ptate through Flange Inspected Bottom Connections Damaged 55f lxx t+ H 5513XX 5515XX . 5517XX 5S1SXX flange crack t+ 5519XX 551axx 5S21XX El” 5522XX Sasaxx 5S24XX u~ Ez 5s2axx El, iwmxx u“ < El 5529XX 5531X.X bolt holes wide S4 Plastic deformation S5 Loose, damaged, or missing bolts Panel PI Damage Zone P2 Crack in contiguity plate weld Damage P3 Damage to doubler plate P4 Crack in doubler plafe weld P5 Partial dep~ P6 Full (or near full) depth crack in column web additional descriptions E of web or plate at bolt holes 5SSSXX 5534XX to continuity plate crack in column web (extension u-” I of C3) EL 554 lxx pfoxx El” S544xf of MRF joint damage as appropria~ .. B-27 SURVEY OF STEEL MRF BUILDINGS DAMAGED BY THE NORTHRIDGE EARTHQUAKE. JANUARY. a 13gmeec mm Date 7994 euiitlg 10 * Pege CcIrlwf .--* SECTION V: Continued - i=- &---6 I I I I I I 10 ---p..J . <-- I ‘/ . (Y G4 * G2 ‘wx3”@ F% P6 REFERENCE 13ETAlL: MRF JOINT DAMAGE TYPES NOTE: sEE SURVEY FORM sEcTION v FOR DEscRIpTKIN B-28 , SURVEY OF STEEL MRF BUILDINGS DAMAGED Ec~oN BY THE NORTHRIDGE JANUARY. 7994 =w-~ mm ** EARTHQUAKE< Page V: Continued Dcl BY TESTING T& I*” I %!? m & 3!!s c3 ONE OR MORE CRACKS WI BY TESTIN REFERENCE DETAIL:MRF DAMAGE TYPES B-29 I ,>. .. pgl SURVEY OF STEEL MRF BUfLD[AfG~ ARTHQUA~ . JANUARY. INSTRUCTIONS mlnu - 7994 TO REPORTING ENGINEER -- : 1. COHPLETE DETAIL FOR SPECIFIC (NOT GEKRIC> JOIW BY ~ILLING IN AU. 2MNKS. 2. S’$T H DAMAGE OBSERVED AT SPECIFIC WIT GCWRICJ ~INT * lKIAL MD ADD ~ $5 TO INDICATE DANAGE TYPE CL TO RE~ERENCE SEPARATE DANAGS TYPE SCHEDM& 3. Cflk!pl El!l INFORMATION BEL13V. BAY SPAN(Ft> _ GIRDER _ (“NOIW”IF ONE-SIDED) MY SPAN(Ft) DIAPHRAGM CQN~TRUCTIU@ _ + ryo(si): — 1 STORY NT. ABOVE CF%)I— 1 J ? —. I - STORY HT BELOW CFt% _ wELDED lo 10 I :1 I I PL t t— 01 0[ 1° 10 10 I I ‘r k.1 2’ * v .BACKING BAR IN PLACE?I _ BOLT DIA: _ CCB4T.PL tI.m,~ 2. 3. U.N.IJ. AS-BUILT 3tMENSf~~ AND sIZEs WWM ~ Stl& SI~ TOP AND BOTTOM SEE PLAN DETAILS fDR ADDITIObL IWORMATION. REFER TO DAMAGE TYPE DETAILls-D~E ~ CXPL~ATIaN DATE VISUALLY FLOOR _ DATE TESTCDI INSPECTED’ _ PROCESS FIELD ~ =? .Dou BLCR P’L %— 0 JOINT DAMAGE TEMPLATE DETAIL - STRONG NOTES: L mll n I I ~ BOLT TYPEI — VSB ~ 01 UBOLT.%_ ( I 01 <~ / ! 7 T AXIS CEIL, ELEV. TOP OR BUTTON m m *GE TYP. T(I BOTH SIDE.% FLAGS. _ FRAME DESR3NATIDN (PER SEPARATE PLAN SKETCH) * JOINT LOCATION IN FRAME CD=CRIB~ AT THIS FLOOR AND FRAML DAHAK ~ R=CR s~wN HOST SIMILAR JOINTS ON THIS FLOOR HAD _ Is — TO SEIWRATE ELEVATION) TYPICAL ND DAHAGf B-30 _ : VQRST CASE “ LESS DANAGL _ sItI!ILAR DANAGE “, . ,.. w RVEY OF STEEL MRF BUILDINGS MAGED BY THE NORTHRIDGE EARTHQUAKE, W JANUARY. Pim - 1994 -w -~c . SECTION vi. Deta ils Of SOWifiC Damaa~ rrnn’ = J* 1NSTRUCTIONS TO REPORTING ENGINEER : L 2. ~HpLETE DCTAIL FOR SPECIFIC 040T GEWRIC) JDINT BY ~ILLING XN ALL BLANKS. ~=CT H WAGE DBSERvED AT sPCcIrIc MT GENERIcJ ~INT ON DETAIL AND ADD ~GS TD INDICATE DANAGE TYPE CL TO RE~CRENCC =PARATE ~ Ty= S-M&E. 6 CDHPMTE 3. lNrDRHATIDN BCLDV. BAY sPANrt) BAY SPAN(F*) — DIAWRA@! CONSTRUCTION/ — + GIRDER:_ WONE’IF OriE-SIDEDJ fY(KSi), — . / \ STORY HT. ABOVE C~t), — — \ Fll t- STORY UT BELOV JOINT BY FILLING IN ALL BLAMCS. &ET H DA14AGEOBSERVED AT SPECIFIC CNDT GEWRIC> JOINT ON DETAIL AND ADD W TYPE SCkEDUIJL 45 TO INDICATE DANAGE TYPE CL Tt3 REFERENCE SEPARATE ~ C&lPLETE IWCIRMATIDN BELUV. r can. PL. VELD BAR . I I : s GIRDER -B (‘ : 1 I e : : c::::::::! I 8 : I 1 I a ; 8 1 @ 8 I * .. BOTTOM FLANGE JOINT IIAMAGETEMPLATE DETi41L- STRONG AXIS PLAN NOTES: 1. SEC COLUMN ELEVATION FOR NEt4BER SIZES DInCNSIONS, AND ADDITIONAL INFCIRHATIDN, 2. RE~ER 10 DAMAGE TYPE DETAIL/SCNEDULE fLUCIR: _ FDR CXPLANATICIN OF DAMAGE FLAGS. FRAHC DESIGNATION (PER SEPARATE PLAN SKi5YCH) t B-31 SURVEY OF STEEL MRF BUILDINGS EARIFGUA~ PA MAGED BY T’ “ NORTHRIDGE JANUARY, 1994 sEcnoN .D’tail s ‘f vi” =’.-> . tc Damaaed ~.: INSTRUCTIONS .— TO w mm - - Jo- RfPORTING ENGINEER : 2. SPECIFIC (NUT GEMRIC> JGINT By ~ILLIffi IN ALL BLAMCS ~GET H DAMAGEOBSERVED AT SPECIFIC CNDT GENERIC> mINT GM DETAIL AND ADD FLAG& 3. TO INDICATE DANAGE TYPE CL 10 REFERENCE SfpA~ATE h COMPLETE INFORMATION BELOV. I. COMPLETE DETAIL FOR DANA= TYPE SCHE- BAR GIRDER BOTTO!4 FLAN6Z JOINT NOTES: i. SK 2. DAMAGE COLUMN ELEVATION TEMPLATE DETAIL - WEAK FOR MEMBER SIZES. REFER TO DAMAGE TYPE DETAIL/SCHEDULE FLOOR:— FRAME DESIGNATION (PER AXIS PLAN DIMENSIONS, AND ADDITIONAL INFORMATION. FOR EXPLANATION OF DANAGE FLAGS. SF-PARATC PLAN B-33 SKETCH) : SURVEY OF STEEL MRF BUILDINGS DAMAGED BY THE NORTHRIDGE EARTHQUAKE. ~4 , -~ r%llt . Due SECTI ON WI: Plan Sketch of B uilding Provide a sketch of the building plan showing the-P-orientation% epadngs, and frsme designations. streat orientatim ID 8: crcu.- Wemll bu~ng dme~ons. *--=* frame locations and .. . SURVEY OF STEEL MRF BUILDINGS DAMAGED BY THE NORTHRIDGE EARTHQUAKE. JANUARY. 1994 auq Engineec Wllc ma Suikiing ID t E ~q v Psge crrlm *~’--f) f Buil [“ rovide one sketch per frame of the frame elevation showing the fmme designation, floor numbering, approximate stoiy heiiht and bay vddth dimensions, and damage locations with reference to damage type ffited on the attached sheet. . .. . B-35 ~ Appendix C: Inspection Testing Criteria and Report Formats S.MITH-E.MERY The FuU kite Co.VP~x Y k@wndenc Testing Laboractmy,&tablished 1904 Date 781 &ascWashm[tanBlui b Angekr, Cdi@lLa v of Issue: July. 11, 19: (X3) 749-w ‘=(=J74%TWSONiC TEST PROCEDUREFOR SEISMICEVALUATION L SCOPE A THIS PROCEDURE COVERS lHE IvEIHODS AND ACCEPTANCE AND REJECTION CRITEMA FOR PULSE-REFLECHON ULTRASONIC EXAMINATION OF POSSIBLE CRACKS IN COLUMN FLANGES. WELD METAL OR BASE METAL OF WIDE FLANGE BEAM MOMENT CONNECTIONS. B. THIS PROCEDURE COVERS SHEm WAVE (AN= BEAM) TES~G M=HODS ~ LONGITUDINAL (STRAIGHT-BEAM) TESTING METHODS USINGCONTA~ TECHNIQUES WITH HANDOPERATED PROBES. C. PROCEDURE REQ~ SPECIFICATIONS. S TO THIS EXAMINATION SHAU CONFORMTO THE FOLLOWING C.1 MrM E-1 14-90 PIL4CTTCE FOR ULTRASONIC PULSE-ECHO S’IRAIGHT-BEAM TES~G THE CONTACT METHOD. C.2 MTM E-164-M STANDARD P%MXK’E FOR ULHONIC WELDMENTS. C.3 AWS D1.I-94 STRUC’TUML WELDING CODE SHX’ION M AND #8. BY CONTACT EXAMINATION OF , C.4 ., ASNT RECOMMENDED PRACTICE SNT-TC-lA 2. EQUIPMENT A INSTRUMENTS Al B. KMUTKMMER ULTRASONIC DETECTOR (TYPE USK4 AND USK-T) TMNSDUCERS B.1 tRANSDUCERS FOR STRAIG~ BEAM EXAMINATIONSHALL HAVE AN ACTIVE AREA OF N~ LESS THAN 1/2 INCH NOR MORE THAN 1 INCH. TMNSDUCERS SHALL BE CAPABLE OF RESOLVING THE lHREE REFLECI’IONS AS DESCRIBED IN AWS DLI SE~ON #6 PAR 6.21.1 WITH NOMINAL FREQUENCIES OF 2.25 MHZ. B.1.A B.2 XNADDITION ATWINCRYSTAL5 MHZ WITH AN OVEWWL DIAMETER OF 1/2 INCH (lOmm - 12mm) MAY BE UTILZED X AN AID FOR DISCONTINUITY SIZING AND RECOGNTI’ION. TRWJSDKER CRYSTALS FOR ANGLE BEAM EXAMINAITON SHALL BE SQUARE OR RECTANGULAR N SHAPE AND MAY VARY FROM 5/8 INCHTO 13/16 INCHIN HEIGHTAND 5/8 DKHTol INcHINw TmH THE MAXIMUMRATIO OF WIDTH TO HEIGIH SHALL BE 1.2 TO1.OAND THE MINIMUM 1.0 TO 1.0 WTIH NOMINAL FREQUENCIES OF 2.25 MHZ. A 45 “,60” AND 70 “ WEDGE SHALL BE USED FOR ALL WELD EXAMINATION. B.2.A WHERE ACCESSIBILITY IS LIIWT’ED A 1/2” DIAMETEFEF2.25 MHZTRAJISDUCERS MAY BE EMPLOYED UTILIZING ANGLES OF 45 “ 60’ AND 70”. SMITH-EMERY .. COXFAXY BOTH TYPES OF TR4.NSDUCERS SHALL MEET THE MINIMUM REQ~S SPECIFIED INAWS D1. I. BASIC CALIBRATION REFLEaORS (3LOCK). B.3 c. D. C.1 HW-BLOCK C.2 BASIC CALIBRATION BLOCKS AS SPECIFIED IN AWS D1.1 AS COUPLANT D:l COUPLANTS USED TO ASSURE TRANSMISSION OF SIGNAL BETWEEN TRANSDUCERS AND THE TEST SURFACE WILL BE CELLULOSE CXRVL=y~ OR ~ AppRO~ MATERLALS. 3. PERSONNEL A SHALL BE THOSE QUALIHED TO TKE REQWREMENT S OF ASNT SNT-TC-IA AS REQUIRED BY THE QUALITY CONTROL SECTION OF THE SMHH-EMERY COMPANY QUALITY ASSURANCE PROGRAM AND THE REFERENCING SECTION OF THE AWS CODE. PERSONNEL WHO CONFORM ARE PERMITTED TO PERFORM THIS EXAMINATION AND INTERPRET THE RESULTS. 4. JOINT CONFIGURATION A THE WELD JOINT ASSEMBLAGE WILL CONFORM TO SKETCH NO. L 5.%WIWACE A ALL SURFACES MUST BE THOROUGHLY CLEANED OF FIREPROOFING, RUST, HEAVY MILL SCALE AND ~ FOREXGN MATTER THAT WOULD PREVENT POSITIVE COUPLING OF THE TRANSDUCER TO THE SCANNING SURFACE SEE EXHIB~ #$ 6. PRETEST VISWAL INSPECTION A A DETAILED INSPECTION SHALL BE MADE PRIOR TO ANY COUPLING MEDIUM BEING APPLIED. OBSERVATIONS WHICH MAY BE INDICATIVE AS INTERNAL FAILURE SUCH AS BACKING DISTORTION, C’&4CKED TACK WELDS, BACKING BAR SEPARATION, OR MILL SCALE DETACHMENT AND COLUMN BLISTERING WILL BE NOTED ON THE REPORT. 7. CALIML4TION A CALIBRATION Al CAJIBl?k’ION FOR SHEAR WAVE (TRANSVERSE) SHALL BE DONE IN ACCORDANCE WITH AWS D1. 1 SE~ON B. NO. 6 PAR 6.21.2. STRAIGHT BEAM B.1 CALIBIUITION FOR LONGITUDINAL MODES HALL BE DONE IN ACCORDANCE WITH AWS D1.1 SECTION NO 6 PAR 6.21.1. c-4 . SMITH-EMERY COMPANY 8. RE-CALIBRATION A THE PROPER FUNCTIONING OF TKE EXAMINATION EQUIPMENT SHALL BE CHECKED AND THE EQUIPMENT CALIBRATED TO THE REFERENCE BLOCKS AS FOLLOWS: Al WHEN THERE ISA CHANGE OF OPERATORS. A2 AT 30 MINUTE MAxMUM A3 AT ANY TIME THE OPEIU%TORTHINKS THERE MAYBE A M.ALIWNCI’ION. A4 WHEN THE ELECTRICAL CIRCUHY IS DISTURBED IN AFWWAY, CHANGE OF TRANSDU~ BAITERJES, COAXIAL CABLES =C. AS IF DUR!NGACHECK IT IS DHERMNED THAT THE EQUIPMENT IS NOT HJKT’IONING PROPERLY, ALL WELDS TESIED SINCE THE LAST VALID CALIBRATION CHECKS SHALL BE RE—EXAMWED. TIME INTERVAL. 9. E?C4MU4Al10N COVERAGE A ALL WELDS AND BASE MATERIALS ASSOCIATED WITH THE MOMENT F3UWE ASSEMBLAGE AS SHOWN KNSKETCH #l SHALL HAVE 100% COVHUIGE. 10. SCANNTNG A ST’MIG~ BEAM Al SCANNING SHALL BE CONDUCTED SO AS TO REVEAL ALL LAM=LAR DEFECTS CONTAINED IN ALL BME MAlERL4LS AND ALL NDICATXONS INCLUDED IN THE WELD MErAL. A2 COLUMN FLANGES WILL BE SCANNED 8 INCHES BELOW TOP BEAM FLANGE AND 8 N3ES ABOVE AND BELOW B~ BEAM FLANGE. COLUMN FLANGES WILL BE SCANNED FROM BU1’H SIDES OF C(3LW IF POSSIBLE AS SHOWN IN SKETCH #l SCAN “D”. A3 SCANNING (Q)LEVELS SHAU BE AS FOLLOWS: a. CONDUCTTHE EXANfDNA~ONWITH A TEST FREQUENCYAND INSTRUMENT ADJUSTMENTTHATWILLPRODUCEA MINIMUM50 TO A MAXIMUM 7S%OFm SCALEREFERENCEBACKREFLECTIONFROMTHEOPPOSITESIDEOFA SOUND AREAOFTHECOLUMNFLANGE. ANAdditional 1SclbsWILLBEADDEDTO THISREFERENCELEVELFORSCANNfNGPURPOSES. INDICATIONS DETECTED AT THE BEAM FLANGE WELD TO COLUMN FLANGE INTERFACE ANDPROPAGATING INTO COLUMN FLANGE WILL BE FUR’IHER EVALUATED UTILIZDIG 70 “, 4S “ OR 60° ANGLE BEAM TRANSDUCERS AS SHOWN IN SKETCH M SCAN “C”. B. SHEAR WAVE B. I “ THE SCANNING PROCEDURE FOR ANGLE BEAM TESTING OF THE TOP AND BOTTOM BEAM FLANGE WELDS SHALL BE AS FOLLOWS: c-5 SMITH-~ a. MER-Y COMPANY TOP BEAM FLANGE WELD WILL BE SCANNED FROM FACE “B” AND BOITOM BEAM FLANGES WILL BE SCANNED FROM BCYI”HFACE “A” AND “B” UTILIZING A 45 “,70” OR 60 TRANSDUCER DEPENDING ON MATHU.AL TWICICNESS. SEE ● SKETCH #l SCAN “A” AND “B”. b. SCANNING LEVELS FOR SHEAR WAVE WILL BE IN ACCORDANCE WTIH AWS SE~ON 6 AND 8 EXCEPT AN ADDITIONAL 6 dbs WILL BE ADDED FOR SC-G PURPOSES. THE INTENT IS TO BE SURE THE DETECHON OF l%E BACKSIDE OF THE COLUMN WHLE WATCHING FOR ANY CRACK LIKE SIGNALS IN EITHER THE WEL.DMENT OR PARENT MATERIAL. 11. ACCEPTANCE AND REJECTION CRiTERLA A LONGITUDINAL WAVE SCAN “ Al B. ANY INDICATIONS DETECTED WITH THE STRAIGHT BEAM PROBE IN lHE VICINITY OF BEAM FLANGE WELD COLUMN D4TERFACE AND PROPAGATING INTO COLU$WNBASE MATERIAL SHOULD BE FURTHER EVALUATED WITH 70”, 4S” OR 60” ANGLE BEAM TRANSDUCERS. SHEAR WAVE B.1 45”,70” OR 60” ANGLE BEAM TRANSDUCERS WILL BE EMPLOYED TO EVALUATE DEDICATIONS AT BEAM FLANGE WELD COLUMN INTERFACE AND INTO COLW FLANGE BASE MATERIAL. SEE SKETCH #l SCAN “A” AND “B”. DISCONT3NUHES DETECTED WILL BE CLASSIFIED IN ACCORDANCE WITH ACCEPTANCE’REJECTION CRITEJUA SEE ATTACHED EXHIBIT MARKED 2. 12. REPORTING A ALL WELDS SHALL BE REPORTED ON SMITH EMERY COMPANY INSP’’WHON REPORT FOR SEISMIC EVALUATION AND AS MODIFIED. SEE ATTACHMENT EXHIBIT’ #3. COPIES ARE TO BE DISTRIBUTED TO THE STRUCTUFW.L ENGINEER AND OWNER ONLY. NO REPORTS WLLLBE DISTRIBUTED TO OTHER INDIVIDUALS OR AGENCIES WITHOUT THE EXPRESSED APPROVAL OF THE OWNER OR HIS AGENT. 13. REPAIR OF WELDS A ALL WELDS WILL BE REPAIRED IN ACCORDANCE WITH THE STRUCTUIU%LENGINEERS APPROVAL AND AWS DL 1-94. 14. REINSPE(XION A ANY REINSPECTION OF REPAIRS TO WELDS SW BE SUBJECT TO THE SAME REQUI=MENTS OF THIS ULTRASONIC PROCEDURE UNLESS SPECIFICALLY STIPULATED BY THE STRUCIUILAL ENGINEER SUli!h-gtrlery Companv fll ri@tsruetvedmduding ri@ts of rqoduuicm Copyighl e 1994. el~icormcchanica &via. wks.s pcnnkial ldcwimprio rn and usc in any form or by my mcana rneludingtk making ofc+u by any#xto fxuu$. or by any tedorwrium orcm&mrwording fwsoundorvisual rqoduaicm afauscin myknowledge orretrival~of writing isobimdh the@@t Qropric!om C-6 SMITH-EMERY COMPANY M. PREPARED BY A NIGEL FALLS-H4ND - B. SIEVE GROVE - ~ 17. APPROVED BY. SMITH-EMERY COMPANY - ASNT LEVEL II YcoMPANY-~LEvELII sr@ c-7 . “. . /. ... . SM~-EmRY COMPANY EXHIBIT 1 .. . r’ . ... . .... .. . ..... . .. .. . . . ...... .. ..... ...... . . . .. surl-c- Sau%” T ; SCA?4NINGPROCEDURE FOR i ; ULTRASONIC TESTING ;. .. .............. ..... .. ...... ..................... I I ? I A BEAMFLANGE ----- 1 1 1 I ,- “1 I 1 I SurrB- L mm . 9ua’’13- WSE ?Ue, 60” OR 45” WHEIE APPuCA$LE USiNGATH RECO~ BOTTOM OF WH.D ONMA~ 8“ FROM TOP AND Y4” AND ~ “(GOTOBACKSIDEOF COLUMN FLANGEE POSSIES D_WG ---- ON OBSTRIJC’130NS) r m’C- /+ 1/2- ‘TRANSDUCERS MAY BE REQUIRED DUE TO BOLT CEARMCE FROM BOROM FIANGE OR RXLY ON SC.ANT USD4G1“ ~UCER I 1 . . . SMITH-E.MERY COMPANY SEISMICEVALUATION ULTMSONIC CLMSIFSCATION ACCepMn*RejtUia criteria *CA~ON ~E * FL4W CHARAC’IERISTICSARE SUCH THAT AN AWS TABLE 83 REIECT CLASSIFICATIONS hLkY NOT BE ACHZEVH). EVALUATIONOF SIONAL Notes 5 on TabIe 8.2. IS OF UTMOST D@ORTANCE. class2 39’pesshown Classl 3 possble paaerns 9> . . . . .0 . .. r . C-9 . Re%IA 7-19.94 COMPAN’f S_-E~RY . SEISMIC EVALUATION RECORD Exmmr 3 FLOOR LEVEL GRID LOCATION BEAM LOCATION UPPER FLANGE_ LOWER WOE. PROJECT NAME PR03ECt ADDRESS cm JOB NUh-fBER Wo NUMBER DATE -7 1 COLUMN FLAME L__.-” -. ------- + ------ -------- --- )-------- COS.LMN FLANGE x. .-.-.- . + co . } . INSPECTOR COGNIZ4NT ENGINEER SIGNATURE SIGN m . ..= ,. . S.WXTX=EMSRY COMPANY” . . EXHIBIT 4 1 g, u CLEANING REQUIREME~S FOR SEISMIC “ EVALUATION b 2$’ I I BUFF TO SOUND ME c-1 1 M~AL r . ... TWINING ~~ LRBORRTORIES #’ IL’%~~ & 6% &$’ TEL:310-426-6424 -UWW-89....-~w U&&l ~ a310AiRww * Nov 15’94 ,10:50 No.O’07 P.02 Qlo) 426-s3s 014) 828-32 L.ons Be8ckCAm p.Q.80X47.90$01 FM (310) 426-6424 AN tESTING 4L-----IM-4I m I I u C-12 \ -:-.... m _lo:51 ~lo Al+ Wff Long So8eh CA 40806 tit REPORT STEELFRAME Mobm coNNm Aw,s DmWrNlm ~ B - MEDIUM D!SCOhW!7iES D?WR mm! 1 TOF J . (W@ mANGE lvw FH[R BGT?OM FLANGE (FUN) c oH?@T4 : .. c-n- P:03 .’ P.o. Box 4?*SoEOl POS7-E4RTHQWE lNsPEcnoN 4- No.067 “-