Force-based elastic seismic assessment of New Zealand unreinforced masonry buildings

Because of the need for a straightforward procedure for assessing the performance of low rise unreinforced masonry structures in New Zealand a force-based, elastic method of analysis for a critical design earthquake is proposed. The comparatively low value of many URM structures in New Zealand justifies a simplified approach and a force-based method has the advantage of familiarity and simplicity. The criteria which the performance of existing buildings must be measured against in New Zealand is defined as one-third the strength of a design earthquake. The procedure for determining the seismic demand to which an existing structure is subjected, as well as how the structure can be analysed to determine the capacity of masonry walls responding in-plane to withstand that demand, are described. It is determined that an equivalent static analysis (ESA) procedure is appropriate for the seismic assessment of low-rise URM structures in New Zealand.