The concept for this five-storey, 10,000m2 library was inspired by the 2010-2011 earthquakes that affected Christchurch, New Zealand, where the majority of buildings remained safe, but a great number were uneconomic to repair and required demolition.
Tūranga’s hidden beauty lies in its level of seismic resilience, such that after a serious seismic event, the shock absorbing systems could be readily replaced and the building would be re-usable.
The massive concrete core walls, some weighing around 140 tonnes, were cast flat on site and then “tilted up”. They provide stability to the building and in a seismic event are able to “rock” due to their connection to the foundations and to adjacent components being made with replaceable shock-absorbing devices. They work in conjunction with a perimeter steel moment resisting frame which also has rocking base connections.
The engineers were instrumental in encouraging plant, that would have been positioned in a basement, to be placed on the roof, allowing the proposed basement to be removed from the scheme. This enables the building to be constructed off a shallow gravel layer, avoiding both the expensive basement and costly piled foundations.
A great example of how structural engineers can make such a crucial difference to a building, this is in every sense - a building that rocks!