The 2010 and 2011 Canterbury earthquakes caused significant liquefaction and lateral spreading to the land beneath the Christchurch Town Hall, which resulted in subsidence and damage to the superstructure.

Christchurch City Council embarked on a $167M+ conservation project that included novel ground improvement, a new raft foundation, re-levelling and strengthening of the superstructure, and interior refurbishment. The restoration project would ensure that the building became a focal point of the Performing Arts Precinct.

The New Zealand Historic Places Trust lists the Town Hall as a Category One building and has been acclaimed worldwide for its architecture and acoustics.

Tonkin + Taylor and Holmes Consulting were engaged to understand how much damage had occurred during the earthquakes to enable estimates for repair. Both engineering consultancies then worked together on the remediation.

Using ground-breaking techniques, our innovative foundation design used 1100 underground cement-mix columns to help stabilise the soil and protect the building from future earthquakes. The work required a delicate touch, as the concrete was jetted seven metres into the ground from inside the auditorium – an architectural and acoustic masterpiece.


  • Geotechnical support to resolve insurance claims
  • Geotechnical design of ground improvement solution in collaboration with Holmes Consulting’s design of the foundation elements
  • Collaboration with the structural engineer and construction team to develop methodology to determine the quality/consistency of the jet ground installation and provide confidence in the solution for the public.
  • Construction observation


  • Christchurch City Council


  • 2011 – 2019


  • 2020 – Silver ACE Award

Explore More Projects

PwC Centre

PwC Centre

Downtown Infrastructure Programme (Quay St)

Downtown Infrastructure Programme (Quay St)



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