Residential Houses - Performance in the Darfield Earthquake (M7.1) 4th September 2010

A report by Andy Buchanan and Michael Newcombe, Department of Civil and Natural Resources Engineering, University of Canterbury

Scope

This report covers the performance of residential houses (mainly single-storey and two-storey houses) in the Darfield earthquake on 4 September 2010. The report is mainly observations of seismic behaviour, although some research areas for remediation and resilience are identified. The report does not cover insurance or building code issues.

Summary

Overall the residential building stock, consisting predominately of light timber frame construction, performed very well.
Very little structural damage occurred due to ground shaking.
The most significant structural damage to houses was from differential settlement of foundations, induced by soil liquefaction and/or lateral spreading.
Many older buildings (more than 20 years old) suffered damage due to falling chimneys.
Close to the fault rupture, in areas such as West Melton and Rolleston, there was significant damage to building contents due to strong shaking, and a few broken windows.
Away from the fault zone, very few windows were broken in any buildings,illustrating the very low level of inter-storey drift.

Building Stock

Liquefaction Induced Damage

Shaking Induced Damage

Damage Due To Fault Rupture

Mitigation Issues - Remdiation and Resilience

Download the full Report as a PDF

Acknowledgements:

This report was prepared by Prof. Andy Buchanan and Michael Newcombe at the University of Canterbury. Assistance with field observations and expert opinion was provided by many people, including the following:

Bruce Deam, David Carradine, Debra Gardiner, Greg MacRae, Greg Cole, James O’Neill, Vinod Sadashiva (University of Canterbury), Andrew King (GNS), Angela Liu, Graeme Beattie, Roger Shelton (BRANZ), Antony Cook, Steve Coll (MiTek), Steve Walker, Warwick Banks (CHH), David MacFarlane, Jeff Parker (Lockwood), Hans Gerlich, Richard Hunt (Winstone Wallboards), Henri Gavin (Duke University, NC, USA), Roger Lough, Members of the Christchurch Earthquake Clearing House.