Epicentral Distance (miles) 22.5 22.0 22.0 14.0 17.0 20.0 20.0 22.0 24.0 20.0 22.5 20.0 22.0 20.0 20.0 22.5 20.0 22.0 20.0 23.0 22.5 20.0 22.5 22.5 22.5 22.0 22.5 22.5 24.0 24.0 Building Equipment ev. broke loose from track ev. cable wts. moved AC fan shifted Beacon light fell ev. cablesjumped ev. wts. moved ev. cables damg. Elev. cables damg. None AC out of adjust None ev. damg. Cable in elev. damg. Slight damg. elev. wts. AC boilers moved None None Elev. wts. loose Slight elev. damg. None AC yoke broke Slight to elev. None None None None None AC moved None None Interior and Contents Earthquake Damage lntr. walls crkd., books fell, furn. damg. All firs. crkd., ceiling tile fell File cabinets, books, light ?xtures fell L&l? walls crkd. all flrs. Filing cabinets over, part. crkd. Part., ceiling tiles damg. Crkd. bsmt. walls (conc.), crkd. Books, lamps, ?le whinet fell Crkd. Walls thruout Slight cracking to crkd. all firs. Slight crkd. Conc. flrs. crkd. 2lst to 25th walls crkd. all flrs. Crkd. all tlrs. cores crkd. stairs elev. Crkd. core, books fell 2 cracks in books fell Crkd. 4th to 14th Crkd., all firs. Stairwell conc. wall crkd. Ceiling tile fell, books fell walls crkd. all firs. stairwell crkd. 4th to 6th Crkd. all flrs. 97,000 Lobby walls crkd. 4th thru 7th part. crkd. Restr. damg. 2nd 45 ,000 Windows lst, 4th, 8th 100,000 Front window Books, pictures fell So. stairwells damg. Crkd. 3rd to 9th Crkd. walls TABLE 14 HIGH RISE STRUCTURAL STEEL BUILDINGS Buildings in course of construction not listed Exterior and Ornamentation Ara? 350,000 Marble facing crkd. *Arca is total square footage above grade 280,000 Windows broke shifted 102,000 Windows 2,5, 6, 8, 9 356,000 Ext. cone. walls crkd. 605 ,000 Window seals broken 700,000 Tile damage ext. walls 750,000 Marble broke in lobby 700,000 None 92,000 Windows 5th 7th 475,000 None 85 .000 Windows 3rd 110,000 Ext. cone. wall crkd. 159,000 None 95,000 Windowsall?rs. 453,000 Marble crkd. in lobby 200,000 Tile loose 231,000 Window crkd. 8th 128,000 Tile facing crkd. 140,000 None 110,000 Cone. ext. walls crkd. 200,000 None 100,000 None 188,000 None 340,000 None 160,000 None 90,000 None 210,000 None Stories Above] Below Grade 6/3 8/1 8/1 8/0 8/1 9/3 10/0 10/1 11/2 12/1 12/1 12]! 12/1 12/1 13/0 13/1 14/0 15/ 2 15/1 15/3 18/1 19/3 22/1 22/1 22l1 24/4 31/1 31/4 32/2 42/ Building information Date 57-59 1955 59-60 63-64 64-65 63-64 63-64 62-63 58-59 55-56 61-63 69-70 67-69 1968 1963 65-67 60-61 62-63 60-61 65-67 55-56 57-58 68-69 61-62 63-64 68-70 63-64 61-64 59-61 60-61 Constr. District Location 9 Downtown LA. 10 HollyWOod 11 Miracle Mile 12 Sunset Strip 13 Westwood 14 Hollywood 15 Hollywood 16 Wilshire 2 Beverly Hills 3 Beverly Hills 4 Van Nays Sherman Oaks 1 Wilshire 6 Sunset Strip 7 Hollywood 8 Beverly Hills 17 Hollywood 18 Westwood 19 Sunset Strip 20 Century City 21 Miracle Mile 22 Hollywood 23 Miracle Mile 24 Wilshire 25 Wilshire 26 WestWOod 27 Wilshire 28 Miracle Mile 29 Downtown LA. 30 Downtown LA. Bldg. No. EARTHQUAKE RESISTIVE HIGH-RISE CONSTRUCTION observed damage patterns were about the same. Flexibly framed buildings, whether concrete or steel, suffered most- ly cosmetic damage on February 9th when relatively stiff stair-elevator and utility cores within the frame experienced large story-to-story relative movements. Elevator cables and the containment of elevator counterweights in the taller buildings were damaged and caused damage, and these fea- tures necessarily must receive more design attention in the future. The greatest reported dollar loss to a completed steel frame building occurred in a 42 story building in downtown Los Angeles, 24 miles from the epicenter. Here, a $200,000 loss to plastered partitions and elevator equipment resulted. Considering a $20,700,000 original investment in 1965-67, the loss represents almost 1% of value. A 22 story steel framed structure built in 1961-63 in the Wilshire District suffered a $100,000 loss, just greater than 1% of value, when an exterior concrete shear wall cracked, ceiling tiles fell and elevator counter balance weights were dislodged. The twin 52 story office towers of the $175 million dollar Atlantic-Rich?eld Plaza Towers in downtown Los Angeles were in the latter stages of construction when the earthquake occurred. Apparently, a 25% increase in the number of cracks in the welds in the two lower stories of both steel framed towers was found after the earthquake, with this increase seemingly due to the earthquake. Minis- cule cracks in the welds connecting heavy metal members occur during the normal welding process and these cracks are normal to this work; routine ultrasonic testing is used to discover these cracks and allow for repairs. It is premature to Speculate very far into this particular case due to the lack of time and detailed information, but the potential problem of earthquake induced weld stress cracks in modern steel frame buildings is disquieting. Additionally, there is no assurance that all welded steel frame buildings will be as adequately inspected as was the Atlantic-Rich?cld towers. The cost of the repair of all welds, regardless of origin, has been placed at $400,000. COMPARATIVE DATA Figures 47 and 48 show dollar losses in terms of cents per square foot of total floor area (above ground) as func- tions of epicentral distance and of types of construction (concrete and steel). Dollar losses include building and equipment repair costs. Occasionally, contents losses were included when they could not be segregated, but these con- tents losses were small and have no significant effect on the conclusions. The following conclusions may be drawn from an examination of ?gures 47 and 48. 39 1. Steel frame and reinforced concrete high-rise generally performed equally well when located 15 to 25 miles from the epicenter, with exception as noted in (4), below. 2. No simple insurance rating or guidelines for story height vs. epicentral distance can be established solely from this earthquake. No doubt, local geology and the building?s natural periods of vibration played significant roles. 3. The loss per square foot was under 15 cents for 82 percent of all examined buildings. 4. Where exceptions occurred to and (3), above, they were usually adverse with reapect to reinforced concrete construction, as follows: Dollar Loss in Cents per sq. ft. Material 680. Concrete 192. Concrete 65.5 Concrete 41.7 Concrete 35.5 Concrete 35.0 Steel 33.3 Concrete 29.5 Concrete 28.3 Steel 28.0 Steel The foregoing experience suggests that reinforced con- crete high-rise buildings will, upon occasion, experience a greater degree of significant damage than will comparable steel frame structures. From a percentage loss standpoint, completed steel frame buildings never exceeded about 1% of value. A total of 5 reinforced concrete structures had losses over and two of these had losses over NON-EARTHQUAKE RESISTIVE HIGH-RISE BUILDINGS Older non-earthquake resistive high-rise buildings per- formed quite badly when compared to modern high-rise construction, based on limited selected information on older structures in the downtown Los Angeles area. The buildings in Table 15 were erected between the years of 1906 and 1916, prior to the enactment of earth- quake requirements in the Los Angeles City code. That is, the engineering design considered only the vertical loadings and not earthquake forces. However, during that construc- tion period, ?reproofing of the steel frames often was a monolithic concrete covering which inherently developed a strong ?composite? structure of steel and concrete. This is not common under present construction methods which employ a sprayed-on light weight asbestos material.