JR undee CHAILVJGING $031. FOR THE TU Dundee House. 50 North Lindsay Street Dundee 1L8 Tel: 01382 434000 If calling. please ask for Fergus Wilson. 01382 434000 Email: fergus.vrilson@dundeeclty.gov uk Our Ref: FWIJM Your Rat Date: 11 November2016 Recycled Paper Dear Sir Independent lnguigy into Construction of Edinburgh Schools refer to your letter of 30 August 2016 requesting information relating to the stability of masonry walls in buildings under the control of Dundee City Council. Please accept my apologies for the delay in reporting but at the time for the request, the majority of investigations had not concluded and it was not considered appropriate to give a substantially incomplete response. Following the incident in Edinburgh, Dundee City Council arranged for investigations to be undertaken of its estate. focusing on properties of similar construction and age to Oxgangs Primary School. For clarity. the properties surveyed were steel/concrete framed structures with an external envelope of "non-load bearing" walls built since 1996. In recognition of the likely direction of any future inquiry. these investigations comprised and properties including education and non-education sectors. Properties Investigations of properties were co-ordinated by Discovery Education pic and were undertaken by the original designer. veri?ed by an independent consulting engineer. The investigations comprised eight schools. In these schools, cavity masonry construction is primarily limited to games halls with timber/metal stud framed wall panels used elsewhere such as the accommodation wings. In line with the initial information from the Edinburgh Schools investigation, investigations in Dundee focused on these areas of cavity masonry wall construction and the interaction of wall panels with the principal structural frame. Initially, non-intrusive visual surveyslinspections were carried out. backed up with reference to as-built drawings. Supplementary intrusive investigation was undertaken where record information was unavailable or where defects were encountered If you have about! understanding {mun please contact the address below digitf?t?fdz?fvf? 1:21:11 man trudnosci jezyka angiclskicgn. skunlakluj of: no ponizcj podsny odrcs: a wage unmeimulmion a. Interrelation Mitchell Street Centre. mu 5m Dudes om 2U 53? I a 19L 01302335815 Fax 01352 435305 {0 Fur information aboul Dundee City Emmi! our website - mlunlluciluoulr 10 November 2016 not obviously attributable to cosmetic issues such as shrinkage or differential thermal movement. In summary. there were no stability issues observed such as lack of plumb, distortion, lateral movement or similar distress. Intrusive investigations were carried out at all the schools. partly due to these being less well documented by construction record photographs. partly to conclude on the cause of observed localised cracking in some of the properties and partly at the additional request of Discovery Education plc. These intrusive investigations, in principle. con?rmed appropriate build quality throughout the prOperties including suitable provision and embedment of wall ties as well as the presence of bed joint reinforcement and wall head restraint. However, at three schools. some de?ciencies were encountered. At two schools. isolated wall panels were found to be missing some bed joint reinforcement andlor some wall head restraint ties. both required by design and speci?ed as part of the construction drawings. The reason for these components being omitted at the noted locations is not apparent but their incorporation in other areas in the same buildings does not immediately suggest an inherent construction issue. The as-installed structural capacity of the affected wall panels was reviewed by Discovery Education's appointed engineers and three wall panels were found to be operating at a factor of safety less than structural design codes require. Retro?tted head restraint was installed to the affected properties in the summer of 2016 and supplementary steelwork in lieu of missing bed-joint reinforcement installed in October 2016. The intent of the steelwork is to subdivide the affected wall panels into smaller areas such that these will operate fully within their original code-compliant design intent. At one school. wall tie embedment was found to be below minimum design requirement at some locations and several wall panels were missing their speci?ed wall-head restraint ties. This has been addressed through installation of retro-?tted wall ties and provision of head restraint to the steel steelwork. Intrusive investigation has still to be completed at one school but this should be completed shortly. Properties properties were inspected by Dundee City Council's in-house structural engineering team. led by an experienced chartered civil engineer. The inspections comprised seven schools and six properties, such as of?ces and car parks. In Dundee?s schools. cavity masonry construction is primarily limited to games halls with timber/metal stud framed wall panels used elsewhere such as the accommodation wings. In non-education sector properties, a similar construction strategy has been adopted with cavity masonry construction generally only used in areas requiring more robust construction such as plant rooms and stairwells. In line with the initial information from the Edinburgh Schools investigation, inspections in Dundee focused on these areas of cavity masonry wall construction and the interaction of wall panels with the principal structural frame. These inspections were in addition to the scheduled cyclical inspections routinely undertaken as part of the management of Dundee City Council's estate by in-house construction professionals. 10 November 2016 Inspections were non-intrusive visual surveys. backed up with reference to as-built drawings. calculations and extensive record photographs/reporting taken by in-house clerk of works during construction. These construction records allowed suf?cient veri?cation without the need to undertake disruptive or intrusive investigations. In summary. there were no stability issues observed such as lack of plumb. distortion. lateral movement or similar distress. Some super?cial cracking was observed at several properties, attributable to non-structural causes such as thermal movement and considered not to be unusual in this form of construction. No de?ciencies were encountered that indicated a need to further examine by intrusive investigation. If you need any further information. please let me know. Yours faithfully x? wit/M? Fergus Wilson Head of Design Property and City Engineer