'Critical factors' in CTV Building collapse during Christchurch earthquake uncovered
A report issued by The Department of Building and Housing in New Zealand into the collapse of the CTV Building on 22nd February 2011 during a devastating earthquake that shook Christchurch has found a number of ‘critical factors’ that contributed to the structure’s demise. In March 2011 the Government ordered an official investigation into the collapse of the Pyne Gould Corporation, Forsyth Barr, Hotel Grand Chancellor and CTV Buildings following the deaths of 184 Christchurch residents. 115 of these fatalities occurred as a result of the CTV Building collapse.
The investigation found the following factors to be instrumental in the destruction of the CTV Building: Intense horizontal ground shaking; Lack of ductility in the columns, making them brittle; Asymmetrical layout of the sheer walls, making the building twist during the earthquake, placing extra strain on the columns. These structural inadequacies also failed to meet the building standards in place when the CTV Building was completed in 1986. Other potential factors mentioned in the report include low concrete strength in some of the critical columns and possible interaction of columns and concrete spandrel panels on the external face of the building making the columns less flexible.
Alan Reay Consultants were accountable for the structure’s initial design and Reay issued the following statement in response to the report findings: “Personally I feel incredibly torn. I have huge empathy for the families waiting for answers, but these reports are technically inadequate. Some of the assumptions made in the reports are highly questionable.” The results of the report - carried out by Hyland Consultants and StructureSmith - have been passed to the police and Institution of Professional Engineers New Zealand for their consideration and possible further action.