About New Zealand Standards related to earthquakes and buildings

Design Standards for construction materials such as timber, steel, concrete, and earth-building are developed in alignment with loading Standards to guide design tolerances.

The attached timeline (see Appendix A) of Standards related to determining earthquake loading shows that the process is evolutionary. Progressively over the past 75 years these Standards have been improved and revised as knowledge about earthquakes, and how to design buildings to resist them, has improved. The last revision was in 2004.

Standards New Zealand technical committees draw on international, regional, and national Standards, recent earthquake learnings, new technologies, and practices as part of the development process.

The following information was received:

1. IPENZ’s overview noted that:

   'Earthquake records show that some buildings may have experienced shaking more than two times more intense than a new building would be currently designed for …'

2. The Department of Building and Housing (now part of the Ministry of Business, Innovation and Employment) noted that:

    '….early indications are that the earth shaking was probably much more violent than designed for in New Zealand’s Building Code, with vertical shaking that was both extreme and unusual.'

   'The Building Code standards are based on the kind of shaking expected to happen about every 500 years, and experts are saying that the shaking that occurred in Christchurch’s central business district may have been as much a three times greater than this.'

We recognise the importance of taking learnings from the two Canterbury earthquakes, and now the major earthquake in Japan, as part of any review of the Standard. We will continue to work with leading researchers including GNS Science, the University of Auckland, the University of Canterbury, BRANZ (Building Research Association of New Zealand) and other industry experts to consider what changes, if any, are required.