NEW Zealand’s politicians have for years failed to act on expert warnings that the nation’s earthquake building regulations are inadequate and that more should be done to shore up older buildings that pre-date current standards.
Win Clark, executive officer of the New Zealand Society for Earthquake Engineering, said engineers had warned that older earthquake-prone buildings should be upgraded to 67 per cent of the standard for new buildings.
Instead, the government had passed legislation in 2004 requiring they reach only 33 per cent of the modern standard.
Councils had to develop plans for such buildings, but because of the high costs they were giving owners long lead times to comply, he said: “Ten, 20, 30 years, because the economic impact would be so great that you would bankrupt the city.”
He said it was clear that current international standards produced buildings that withstood even an earthquake of last week’s unexpected intensity: “All the [Christchurch] buildings that were built since the last major code was developed have survived and performed exactly as expected. Sure, they have cracks — there were cracks in the beams — but that was what was expected.”
Mr Clark declined to comment on the safety status of the buildings at three sites that collapsed and killed scores of people.
Jason Ingham, associate professor of structural engineering at Auckland University, confirmed engineers believed 33 per cent was too low. “If you improve your building to only one-third of the building standard, it is still 20 times more likely than a modern building to fall down in an earthquake. At two-thirds, it’s only something like three times as likely to fail.”
He said New Zealand had about 3600 masonry buildings that were at risk because they were unreinforced. Christchurch council’s quake policy says it has up to 7600 earthquake-prone commercial buildings, most of them built before 1976.
After the September earthquake, the council strengthened its policy to include the target of 67 per cent for old buildings. But the policy says: “If the building was not damaged by the recent [September] earthquakes then the owners may have 10 to 15 years, from July 1, 2012, to complete the required earthquake-strengthening work.”
The council was unable to respond yesterday to requests for details about the age and standards of the collapsed buildings.
Retrofitting of old buildings was extremely expensive and could make some businesses unviable, New Zealand Business Minister Maurice Williamson said last night. He said viability would be threatened if owners were asked to do too much too quickly, and then “you send the country bankrupt”.
Asked whether it would not be cheaper to retrofit than to endure again the human and economic cost of the Christchurch quake, Mr Williamson said any reasonable work should be done and done quickly, “but it comes down to how fast and how severe you need to be about that retrofitting”.
He agreed that the inquiry into the disaster announced by Prime Minister John Key might need to examine whether responsibility for building safety should be at the federal level, rather than left to local councils.
The confirmed death toll from last week’s earthquake stands at 160, with the final figure expected to be about 240.