Work progressing to identify earthquake prone buildings - 4/04/2011

The Building Act 2004 requires each territorial authority to have an earthquake prone building policy for its district. The policy is intended to address how earthquake prone buildings can be made to retrospectively comply with current seismic building codes.

The Wanganui District Council adopted its initial earthquake prone building policy in June 2006 and adopted a revised version in 2009 during the 10-Year Plan review.

“We have a planned approach to get better information on publicly and privately owned buildings that may be earthquake prone,” Deputy Chief Executive Julian Harkness said.

“Any building that is not up to 33% strength of a new building is seen as a potentially earthquake prone building. We know that Wanganui has a number of potentially earthquake prone buildings by reason of their age and construction.”

The only effective way to determine whether a building is earthquake prone is for a qualified engineer to do an Initial Evaluation Procedure (IEP). As many buildings in Wanganui have not had an IEP it is not known how many earthquake prone buildings there are. However, it is expected there will be a large number.

Over the years, building standards and safety have generally improved and newer well maintained buildings are less prone than older unreinforced masonry buildings. Some significant changes to building construction and earthquake strengthening occurred in 1933 due to the Napier earthquake and in 1976 after a new building regulation was enacted.

“We believe that during the past decade fewer than 10 buildings in Wanganui have had building consents that also required included earthquake strengthening work. The costs of earthquake strengthening are substantial and council acknowledges the impact these requirements will have on building owners. However, we encourage building owners who are contemplating doing work on their properties to consider doing the earthquake strengthening at the same time.

“Wanganui’s Old Town area is part of the district’s unique heritage and we are keen to ensure that is preserved while at the same time ensuring safety.

“The council has started working on a facades and parapets policy for CBD buildings. An initial assessment will be done to determine which buildings have potentially dangerous parapets and facades that could pose a risk to the public in the CBD during an earthquake. A policy will then be developed to detail what work needs to be completed to deal with the risk of falling parapets and building facades in an earthquake. This risk was a lesson learnt from the 2007 Gisborne earthquake which has been demonstrated again in Christchurch.”

Mr Harkness said the council is interested in central government’s response to the Christchurch earthquake and whether there will be any changes to building standards as a result.