Rebuilding Christchurch following the Canterbury earthquakes – implementation of geotechnical lessons learnt

Abstract

Liquefaction during the Canterbury Earthquakes caused significant damage to the built environment of Christchurch and posed a significant challenge to the rebuild effort. This paper describes the process the geotechnical engineering community went through to overcome this challenge, and how the lessons learned and the new knowledge acquired has been used to design and construct new buildings in Christchurch. The first part of this paper describes key lessons learnt from the earthquakes, summarising information from land damage mapping throughout Christchurch from four major earthquakes. The second part of this paper summarises research projects carried out by MBIE in 2011 to assess foundation performance using blast‑induced liquefaction techniques. One key finding from both the damage observation and the research projects was that the thickness and strength of the non-liquefiable crust layer has an enormous impact on the occurrence and severity of land damage in the earthquakes. The final part of this paper describes how this lesson has influenced the foundation design for new ‘anchor projects’ in the Christchurch CDB, including the Justice and Emergency Services Precinct, the Christchurch Hospital Acute Services Building, Canterbury Multi Use Arena, Te Pae Christchurch Convention Centre, the Tūranga Central Library and the repair of the Christchurch Town Hall.