Identifying Heritage Value in URM Buildings

Abstract

A large number of the heritage buildings in New Zealand are constructed from unreinforced masonry (URM). These buildings were not designed to resist seismic loads and now pose the highest earthquake risk of any building type due to the inherent weakness of the material and several key structural deficiencies. Many of these buildings will require seismic retrofit in order to meet the requirements of The Building Act 2004. URM buildings are a salient part of the culture and landscape of New Zealand, and it is vital that their important aspects are identified prior to any strengthening work. This identification process will inform the selection and design of an appropriate seismic retrofit intervention and ensure that a solution which is sympathetic to the heritage and aesthetics of the building is achieved. The primary aim of this article is to reconcile the engineering goal of seismic strengthening of at-risk heritage buildings with the architectural goal of ensuring that their historic and aesthetic qualities are retained. This article is intended to assist structural engineers in recognising the important heritage aspects of URM buildings, but it is emphasised that this is not a substitute for the engagement of a professional heritage consultant.