Assessing the Seismic Performance of Existing Reinforced Concrete Buildings in New Zealand

The 2011 Canterbury earthquake in New Zealand motivated a revision and enhanced standardization of protocols for the assessment of the earthquake risk of existing buildings across the country. The resulting document arising after significant consultation and discussion is the 2017 publication “The Seismic Assessment of Existing Buildings Technical Guidelines for Engineering Assessments”. The document provides guidelines on determining whether a building should be rehabilitated after an earthquake. This article is written primarily with the objective of providing a notion of how seismic assessment practice has changed in New Zealand since the Canterbury earthquakes in the context of these new technical guidelines. The procedures within the ISA (Initial Seismic assessment) and DSA (Detailed Seismic Assessment) are discussed. Two cases of the assessments being applied are then presented, the first example being that of a four-story reinforced concrete building in Auckland, an area of relative low seismicity, and the second example which is a four-story reinforced concrete building in Wellington, an area of very high seismicity.