View of the outside courtyard of the Trafalgar Centre; View of the outside courtyard of the Trafalgar Centre;

Trafalgar Centre Revised Hazard Assessment, Nelson

Bringing community back to Nelson

Nelson City Council on New Zealand’s South Island wanted to bring new life back into a local icon – The Trafalgar Centre, an indoor events centre - which had been closed due to fears it would not be able to withstand a moderate earthquake. Arup was brought on as geotechnical earthquake engineer during the project, found a serious issue and designed a customised solution.

Project Summary

67% New Build Standard retrofit

NZ$12.9Mretrofit cost

In a region prone to earthquakes, communities want life to be able to go on, and making sure public buildings are robust if the worst happens is a big part of this. 

The Trafalgar Centre is a multipurpose complex used for sport, concerts and events. An important feature of the city, it had been closed due to heightened concerns of the risk of collapse during a moderate earthquake. The centre was undergoing a redevelopment in 2014 when Arup was engaged to assess issues around liquefaction.

Arup provided Council with advice based on a revised hazard assessment using state-of-the-art procedures, including site specific seismic hazard, ground investigation, liquefaction triggering and foundation damage assessments. 

Arup’s advanced seismic engineering capability helped to develop cost effective solutions that were also safer and more environmentally sustainable to implement than previously proposed alternatives.

Arup provided concept and detailed design services for the ground improvement and foundation retrofit works and support the revised structural retrofit solution to the super structure developed by Holmes. We delivered:

  • targeted ground improvement in the form of deep soil mix columns to isolate the building from the stream channel and potential ground movements associated with lateral spreading and co-seismic slope movement 

  • retrofit of the structural foundation support system to include new augmented shallow foundations, providing redundancy in the event of a loss of pile axial capacity

  • and tension ties to maintain a lateral connection between the seating galleries at the base of the arch, providing additional resistance to potential differential ground movements across the width of the building. 

The solution was not only practical from a performance requirements’ standpoint, it allowed Nelson City Council to meet its timeline and budget.

Life has poured back into The Trafalgar Centre once again as the 50,000-strong community embraces its newly-renovated, safer centre.