Earthquakes and existing buildings New Zealand experience 1968 to 2008

摘要

Ever since the Napier earthquake in 1931, New Zealand has taken earthquake engineering seriously.Developments in design standards and seismological knowledge over the years have resulted in acurrent building stock with a wide variety of expected performance when compared with new buildingstandards. This paper traces the main developments in design since 1935 and the efforts to addressdeficiencies in older buildings, from the first legislation in 1968, which covered masonry buildings, tothe latest experiences with the implementation of the Building Act 2004. The 2004 provisions coverall buildings except small residential building and define the level at which and existing building isregarded as earthquake-prone and thus could be subject to a requirement to “reduce or remove thedanger”. The Act required each of New Zealand’s 73 territorial authorities to develop a policy onearthquake-prone buildings, to consult publicly before adopting it, and to submit it to the Departmentof Building and Housing. The approach, priorities and details of policies were up to each territorialauthority.The paper outlines how New Zealand has sought to reduce earthquake risk in existing buildings overthe last 40 years and to deal with the complex mix of technical, social, heritage and economic issuesinvolved. It is hoped that this examination of the New Zealand experience will be instructive to thosein other countries seeking to address the risks represented by existing buildings.The author is a past president of the New Zealand Society for Earthquake Engineering and a formerDirector of IAEE. Since the mid-1980s he has been closely involved in the development of two sets ofguidelines for assessing and retrofitting existing buildings (in 1986 and 2006). He had a key role inpushing for the 2004 legislation on behalf of NZSEE and since 2003 has provided advice to the NewZealand Department of Building and Housing on earthquake-prone building legislation, including thedevelopment of guidance material for territorial authorities to help them write earthquake-pronebuilding policies.