DON SCOTT/Fairfax NZ
UNIQUE STRENGTHENING: The Christchurch Art Gallery will be lifted off the ground as part of a planned earthquake strengthening. Base isolators will be fitted to limit its exposure to shaking in a big quake.
The building served as Civil Defence headquarters in the weeks after the September 2010 and February 2011 quakes.A $36.7 million project to earthquake-proof Christchurch Art Gallery will see the striking glass-fronted building lifted and reinforced to protect it from further ground shaking.
It suffered no major structural damage, but it is no longer sitting level.
The city council has decided that since it will have to jack up the gallery to level it, it should also install base isolation technology that should lessen the building's exposure to ground motion in another big quake.
It is negotiating to buy a neighbouring property so that it can start work and provide a one-metre buffer around the gallery so that it can move in a quake without hitting anything else.
Council community services general manager Michael Aitken said the timeframe for doing that work and the other repairs was not yet clear as the project was still in its design phase. It was likely the gallery would remain shut to the public until the end of next year - longer than the council had anticipated.
"The huge advantage with the base isolation is that it will make the building very resilient when an earthquake happens," Aitken said.
That was important not just for the safety of the public but also for the safety of the artworks in the gallery.
It was vital the building was perceived as being strong and safe as the gallery had only a small collection of its own and relied heavily on collections on loan. "We want to be able to give the people who are lending us these fabulous artworks the confidence it is a safe place to put them," Aitken said.
Stefano Pampanin, an associate professor in structural design and earthquake engineering at Canterbury University, said retrofitting base isolation to the gallery was "a brilliant idea".
"It costs more than doing it from scratch, but if the council is lifting the building anyhow it makes sense to do it," he said.
"With modern buildings, the foundations are typically very good, so all they have to do is go underneath the building, jack it up and fit a slider."
Pampanin said the technology was widely used in Japan and had also been used at Christchurch Women's Hospital. It was proven to significantly reduce the accelerations and forces in a building during a quake.
Base isolators are also being used in the construction of a seven-storey office building on the corner of Montreal and Hereford streets.