Rank safety of buildings - engineer
A Kiwi engineer who pioneered earthquake-resistant building design in the United States is backing calls for seismic ratings on Christchurch buildings.
Ron Mayes, a San Francisco-based structural engineer and base-isolation expert with 40 years' experience, was in Christchurch yesterday to give a presentation on better building performance.
His firm, Simpson, Gumpertz & Heger, has joined forces with Christchurch engineering consultants Opus to repair the 126-year-old former municipal chambers on the corner of Oxford Tce and Worcester Blvd, for which base-isolation is being considered.
Mayes backed an initiative being investigated by the Christchurch City Council where buildings would receive publicly displayed ratings based on how they shape up against the building code.
However, it should not be regulated by local or central government, he said.
"It's my opinion, it's a market-driven system where it's imperative that people know what performance the building they live in or work in is," Mayes said.
In Japan, base-isolated buildings were rented and sold at a 10 per cent premium, which paid for the additional engineering costs.
Mayes moved to the US in the early 1980s to promote base-isolated design, which allowed buildings to move with quake shaking.
The technology caught on there and in other quake-prone countries, but not New Zealand. However some notable examples include Christchurch Women's Hospital, Wellington's Te Papa museum and a retrofit of the capital's Parliament Buildings.
"Selling safety - doesn't matter if it's cars or structural engineering - is the hardest sell in the world, especially if it's higher initial costs," Mayes said.
There were few tests for the technology until a spate of major quakes in the 1990s, he said.
In the 1994 quake in Northridge, California, a hospital sustained $400 million of damage and its new cancer research unit was "trashed".
The neighbouring eight-storey building at the University of Southern California, which had been base isolated, was undamaged. Video footage from inside a four-storey hospital during Japan's 2011 quake also proved the benefits, he said.
"The strong shaking was for two minutes and you see the whole hospital moving. It stopped shaking and they were ready to bring patients in. It was just like what we want a hospital to be after an earthquake," he said.
Software had been developed that could estimate the cost of damage and downtime while buildings were out of action for repairs.
"The benefits have never been quantified before. We as a profession think of the structure, but we don't think of the architecture, the contents, or the mechanics, which is 80 per cent of a building's cost.
"That's the stuff that gets whacked in an earthquake."
The engineering profession failed in the 1980s and 1990s to "really tell people what our [building] codes delivered".
The hardest thing was getting across to owners and architects that a code-designed building was life-safe and "you may have to take it down after an earthquake", Mayes said.
"Most people think, even today I bet, that if [they] get a code-designed building, [it's] earthquake-proof. That's nonsense."
Next week the University of Canterbury will open its Quake Centre, which will become the national hub working with industry on joint venture earthquake engineering research projects.
The centre will be opened at the Westpac Hub in Addington on Thursday. Pro vice-chancellor (engineering) Jan Evans-Freeman said it would "build on New Zealand's established reputation for excellence and innovation in earthquake engineering".
AT A GLANCE
Base isolation is a technique developed to prevent or minimise damage to buildings during an earthquake. A fixed-base building (built directly on the ground) will move with an earthquake's motion and can sustain extensive damage as a result. When a building is built away (isolated) from the ground, resting on flexible bearings or pads known as base isolators, it will only move a little or not at all during a quake.