The Canterbury Earthquakes Royal Commission (CERC) was formed in recognition of the importance of reviewing the performance of buildings in the Christchurch central business district (CBD) during the earthquakes. It considered the adequacy of current legal and best-practice requirements for building design, construction and maintenance. Issues considered in detail included:
a) seismicity
b) soils and the seismic design of buildings
c) the performance of CBD buildings
d) low-damage building technologies
e) earthquake-prone buildings
f) building management after earthquakes
g) roles and responsibilities within the current regulatory
h) framework.
The CERC Final Report on the lessons learnt and recommendations provided was published in June 2012. The seven volumes contained 189 recommendations, of which 175 were assigned to Ministry of Business Innovation & Employment (MBIE) to action. These seven reports can be found on this link: https://canterbury.royalcommission.govt.nz/Final-Report—Summary-and-Recommendations
Volume 1 covered many of the issues most relevant to geoprofessionals although a number of geotechnical recommendations are scattered throughout the other volumes as well. The full list of recommendations is included in Volume 7. Table 1 below summarises the CERC recommendations.
Subsequently MBIE prepared a formal CERC response to outline what actions had been taken to address the recommendations, and this report was published in February 2017. For the MBIE responses, you need to follow this link: https://www.mbie.govt.nz/assets/27c53c4193/responses-cerc-recommendations.pdf.
It is strongly recommended that all geoprofessionals familiarise themselves with the background behind the CERC geotechnical recommendations – for easy reference the relevant recommendation numbers are collated in pages 1 to 12 and 70 to 81 of the MBIE response report, where most (but not all) of the geotechnical recommendations are well summarised. In reality, there is more to be learned by reading the background to each recommendation than the recommendation itself as these were necessarily economic in their wording.
The Society can take great pride in being closely involved in the response to the majority of the geotechnical related recommendations, as most obviously demonstrated by the preparation of Geotechnical Earthquake Engineering module series 1 to 6 as well as other initiatives – commonly in partnership with MBIE and EQC.
The modules provide internationally reviewed state of practice guidance on many aspects of earthquake geotechnical engineering in New Zealand, and would not have been possible without the support of MBIE and EQC. We are fortunate to have them, and the ongoing task now is to keep them in regular use and to periodically update them to keep them current.
Reading the CERC report it was clear that there was a trend over many years towards insufficient attention and investment being given to fully understanding the performance of the ground under seismic shaking and appreciating its relationship to the overall performance of buildings. Recognition of the importance of good quality geotechnical advice in structural design has risen substantially as a result of the Canterbury and subsequent Kaikoura earthquakes. It is important that we collectively as an industry don’t let time and complacency dilute this position. Once the current modules are formally finalised over the coming two years, the Society will need to plan for their ongoing maintenance and periodic updating.
Table 1. Summary of CERC’s geotechnical recommendations
