Release time : 2015-06-11 08:41:32
By Bearing Manufacturer>Bearing News>Push for Kiwi bearings in quake city rebuild
Only one building in Christchurch, the city's women's hospital, was protected by Kiwi "base isolating" technology using lead-rubber bearings to allow it to move as the earth moved.
Invented by Dr Bill Robinson and developed by Wellington- based Robinson Seismic, the bearings have proved their worth during major earthquakes, including Kobe in Japan and the 1994 Los Angeles quake. But outside of Wellington, use is limited, partly due to cost.
The bearings work by isolating buildings from the ground, allowing the structure to move flexibly during violent shakes.
Robinson Seismic business development executive Geoff Leech says using lead rubber bearings in key buildings should be strongly considered during the rebuilding of Christchurch.
"I think it would be almost a crime if serious thought wasn't given to using them," he says.
However, he says, changes are not likely until after technical reports and commissions of inquiry have been resolved.
"I wouldn't expect to see any major changes until those are largely dealt with," he says.
Although only one building in Christchurch was fitted with the bearings, many key buildings in Wellington are base-isolated, including Parliament, Te Papa and Wellington Hospital.
Leech says the high uptake in Wellington is related to people's perception of risk.
"In Christchurch, for example, people's mindsets have changed in the last nine months," he says.
The only building in the city with lead rubber bearings was Christchurch Women's Hospital, which was built in 2005.
Leech says he understands the hospital survived the quakes with no structural damage.
"The building performed very much as expected," he says.
"It continued to function during the earthquakes and was functional straight afterwards."
He says the contents of the hospital were also protected.
"You didn't have lots of things falling off shelves or machines tipping over."
Dr Quincy Ma, a civil engineering lecturer at the University of Auckland, says the main barrier to using the system is cost. "It is hard enough to convince building owners and developers to spend money on the design process, let alone trying to convince them to spend more money in case of a very rare but disproportionately devastating event."
Lead rubber bearings cost between $5000 and $15,000 each, with 30 to 100 bearings typically installed for a mid-sized building. They can be retrofitted to existing buildings or included during construction.