Engineers call for seismic technology in new construction
Media release – for immediate
August 9 2011
Available, affordable and here. Earthquake engineers call for seismic technology in new construction
Advanced, cost-effective earthquake resistant technology, essential for the rebuilding of Christchurch and all future construction in New Zealand, is already available here says the New Zealand Society for Earthquake Engineering.
NZSEE Executive Officer Win Clark said that base isolation and Precast Seismic Structural Systems (PRESSS) should be considered for all new buildings of up to nine storeys, and other technologies are available for more high-rise construction.
“The base isolation and PRESSS techniques have already been put to the test under extreme conditions in Christchurch,” said Mr Clark. “The Christchurch Women’s Hospital, which is base isolated, and the Southern Cross Endoscopy building, which is built using PRESSS technology, have both performed very well in the recent earthquakes.
“Not only are these technologies effective in mitigating the damage caused by earthquakes, they are also quick to build and cost effective. These should be used, where appropriate, for the construction of all new buildings in New Zealand.
“It is absolutely essential that those responsible for decisions on the rebuilding of Christchurch, central and local politicians and building developers, investors, designers, contractors and the general public countrywide understand how effective these technologies are and that they are already being used in New Zealand.”
Base Isolation, originally developed at Industrial Research at Gracefield, near Wellington, involves the superstructure of the building being separated from the ground by rubber bearings with lead inserts to provide damping of the building’s sway motion.
It is now used worldwide for building protection against earthquakes. As well as the Christchurch Women’s Hospital, buildings constructed using base isolation include the Museum of New Zealand Te Papa and the Wellington Hospital.
PRESSS uses un-bonded post-tensioning to allow controlled rocking of a structure’s joints. This softens the blow of an earthquake, springing the building back to upright without significant structural damage even after a major seismic event.
There are already eight PRESSS buildings in the US and four in New Zealand. The Southern Cross Endoscopy building and the Alan MacDiarmid Building at Victoria University of Wellington were both built using PRESSS precast concrete.
A team led by Professor Andy Buchanan and Associate Professor Stefano Pampanin of the University of Canterbury adapted the PRESSS technology for use with Laminated Veneer Lumber (LVL) using New Zealand grown Pinus Radiata. The Nelson-Marlborough Institute of Technology (NMIT) and the newly-completed Carterton Events Centre in the Wairarapa have been built using this PRESSS timber technology.
“The beauty of PRESSS technology is that it can be used for both precast concrete and timber frame buildings that are quick to build and cost the same, or slightly less, than conventional construction,” said Mr Clark.
“Base isolation is slightly more expensive – around four per cent – to build but life cycle costs are significantly less than conventional construction.”
Mr Clark said that other technologies were required for buildings of ten storeys or more.
“The University of Auckland is carrying out very good research in this area and technology for high-rise buildings, such as the steel frame and slip joint technique, is also already in use in New Zealand,” he said.
“Examples of this include the Te Puni student village at the Victoria University of Wellington. This has used a bolted steel frame with controlled slipping of the beam joint. Under a seismic sway, the bolting of the bottom flange slides relative to the bracket connection to the column.”
The Alan MacDiarmid, Endoscopy building and NMIT building have just been named as award-winners in the Association of Consulting Engineers INNOVATE Awards of Excellence 2011. The Te Puni building was an award winner in 2010.