Laying The Foundations – The Building (Earthquake Prone Buildings) Amendment Bill

The following is an article written by Ms Anya Reardon, Solicitor, Litigation and Dispute Resolution Team, Hesketh Henry.

“The Building (Earthquake-prone Buildings) Amendment Bill is currently before Select Committee. According to Building and Construction Minister Maurice Williamson, an estimated 15,000 to 25,000 earthquake-prone buildings will be identified through assessments within five years of legislation taking effect. Those building owners will then have another 15 years to carry out strengthening work or have buildings demolished.

“On 6 August 2014 the Litigation Team at Hesketh Henry hosted a seminar that focused on the discussion of issues around insurance, financing and policy measures in relation to the new legislation and its wider economic and social impact.  The speakers included Alan Sherlock, one of the litigation partners at Hesketh Henry, Sean Gardiner, senior engineer at Spiire, and Brendan Sutherland, regional manager specialising in commercial property finance at ANZ.  

“The discussion centred mainly around the definition of earthquake-prone buildings and what should be done in terms of strengthening to bring them up to the required 34% of the new building standard (NBS).  Mr Sutherland mostly considered financial repercussions for the owners of the earthquake-prone buildings.

“Mr Sherlock defined an earthquake-prone building as one “that will have its ultimate capacity exceeded in a ‘moderate earthquake’ and would then be likely to collapse causing injury or death to persons in or around the building, or damage to other property.”  Mr Gardiner reminded the audience that an earthquake-prone building is one that is less than 34% of the NBS.

“In Mr Gardiner’s opinion, the first thing owners of earthquake-prone buildings should do is talk to a structural engineer or their local council about getting a strength assessment done.  If the building was built before 1976, Mr Gardiner recommended to go with a DSA (Detailed Seismic Assessment).  If it was built after 1976, an ISA (Initial Seismic Assessment) was likely to be sufficient for a start.

“Mr Gardiner then identified the differences between the two methods: ISA was qualitative (based on age, construction type and location, among others).  ISA was usually cheaper to carry out but its accuracy was very coarse and it was more suitable as a tool for identifying whether a building was likely to be earthquake-prone or not. A DSA is quantitative, meaning it was based on specific calculations.  DSA was more accurate and therefore also more expensive. However, its ability to determine the strength hierarchy and optimised target strengthening level was worth the money.

“When discussing options for increased strength and seismic performance, Mr Gardiner stressed that these should be determined on a case-by-case basis, but would generally mean ‘tying the building together’.  This involved the strengthening of the diaphragms, bracing of the roof and connections, installing additional super-structures and foundations and/or fitting of high-end protection devices such as viscous dampers or base-isolation.”

For further information on Hesketh Henry go to www.heskethhenry.co.nz .