The New Zealand Building Code - a rethink?

Abstract

Are the regulatory settings for structural and geotechnical design of structures in New Zealand currently appropriate? It is contended that they are not. New Zealand led the world in performance based building regulation when the Building Code was first established in 1992. The Building Code reflects societal expectation of performance, what people are prepared to accept balanced against how much it will cost. Clause B1- Structure has remained essentially unchanged since that time, focused on life safety and not damage. Meanwhile we have experienced a significant spike in seismic activity with historically unprecedented losses and disruption. It is clear that perception of earthquake risk is very different to what it was in 1992. Internationally there has been a significant shift to providing greater clarity and specificity for the regulatory outcomes being demanded within the building code system. The goal of the 2006 Building Code review was attempting to do this. Unfortunately, apart from the C clauses for fire safety causing significant issues in implementation, this has not happened. Standards supporting the Code have however been changed, reflecting improved understanding of system performance and capacity. This cannot be said for seismic hazard, where demand parameters for design are two decades out of date despite our increased understanding. The idea of providing more specific tolerable impacts for various levels of shaking has been proposed, but so far this work has not progressed. The paper proposes key steps to be followed if New Zealand aspires to best practice building regulation.