Media release issued by the Department of Building and Housing: Technical Investigation report released
30 September 2011
Strong ground shaking and extremely high vertical accelerations were among the principal reasons why three key Christchurch buildings failed in the 22 February earthquake, the Department of Building and Housing announced today.
The Department today released its report from its technical investigation into three large multi-storey Christchurch buildings - Pyne Gould Corporation (PGC), Forsyth Barr and Hotel Grand Chancellor buildings.
The investigation has been conducted by leading New Zealand engineering consultants and their findings peer reviewed by a panel that includes experts with international experience and standing.
Department Deputy Chief Executive Building Quality, David Kelly, said the technical investigation into the fourth building – the Canterbury TV (CTV) building – was still ongoing and that report and the final recommendations from the expert panel involved in the investigation would be released when it was completed.
“The investigation into the CTV building is incredibly complex. It’s important the time is taken to conduct a thorough investigation to ensure the findings are robust.”
Mr Kelly said the recorded ground accelerations in the 22 February earthquake were markedly greater than those in the 4 September 2010 earthquake. The recorded values of peak vertical accelerations in the Port Hills were among the highest ever recorded anywhere in the world.
The report released today found the PGC, Forsyth Barr and Hotel Grand Chancellor buildings failed principally because 22 February was an extremely violent earthquake and, when they were built, design requirements were not as rigorous as they are now.
“In the case of the PGC building, where there was tragic loss of life, the shaking was much more intense than the building was designed for when it was built in 1966. The building lacked resilience and the ability to move and respond without losing strength.
“Based on the findings, the expert panel has made a number of recommendations to improve building standards and best practice. The Department is taking action on all the recommendations with immediate focus on the panel’s priority recommendations,” Mr Kelly said.
“Today we issued an alert to structural engineers and local authorities to ensure that owners of multi-storey buildings have all the main exit stairs checked. This is to ensure they have sufficient allowances for movement.
“We are also working with the Structural Engineering Society of New Zealand (SESOC), the design profession, and Standards New Zealand on aspects of design, building detailing and construction.
“The report and its recommendations have now been referred to the Royal Commission of Inquiry looking into the Canterbury earthquakes.”
A copy of the technical investigation reports released today can be downloaded from the DBH website: http://www.dbh.govt.nz/canterbury-earthquake-technical-investigation