New plans for earthquake strengthening
HAMISH RUTHERFORD AND MICHELLE COOKE AND CATHERINE HARRIS
All earthquake-prone buildings will have their seismic assessments made public under changes proposed in response to last year’s Canterbury quake.
Commercial and multi-storey residential buildings across the country will have to be assessed for seismic strength within five years, with the findings of those assessments made available on a public register, government recommendations released today stated.
If owners do not comply with the assessments’ findings – which may include orders to strengthen or demolish their properties – then the Government may enforce measures to ensure the building is unoccupied, Building and Construction Minister Maurice Williamson said.
But the Royal Commission, which released 36 recommendations on earthquake-prone buildings, said local authorities should have the power to demolish the buildings if the owners don’t.
The commission released its findings into the failure of 21 buildings during the Christchurch earthquake in February 2011, in which 42 people were killed. A total of 185 people were killed in the quake, including 115 in the Canterbury Television (CTV) building and 18 in the Pyne Gould Corporation (PGC) building.
The commission’s recommendations include changes to New Zealand’s building legislation. The Ministry of Business Innovation and Employment (MBIE) made its own proposals, which form part of a consultation document.
Consultation on the ministry’s proposals begins today and ends on March 8.
The ministry’s proposals outline recommendations for how to handle the estimated 15,000-25,000 non-residential or multi-unit or storey residential earthquake-prone buildings in New Zealand. An earthquake-prone building is defined as one that is likely to collapse in a moderate earthquake or which is less than 33 per cent of the building standard.
The commission’s document, which follows a year-long review, recommends a national policy for assessing buildings, as well as cutting the time that owners have to strengthen earthquake-prone buildings, from an average of 28 years, to just 15 years.
The commission recommends all unreinforced masonry buildings be strengthened or demolished within seven years and gives a 15 year timeframe for all others, while the ministry recommends 15 years for all.
While most of the recommendations do not relate to stand-alone one-storey residential properties, the commission has also recommended that all “hazardous elements” including unreinforced masonry chimneys, on all buildings should be reinforced or dismantled.
The ministry has said that a number of proposals will become law, but wants to consult widely with the public and key stakeholders before making any decisions.
Crucially, the current threshold for earthquake-prone buildings, often referred to as 34 per cent of the new building standard, will not be raised – a point agreed by both the commission and ministry.
Williamson said it was a matter of balancing safety and cost.
“We finally need to come to a position where we land on that safety versus cost curve...we can’t stay on the level of the curve we are currently at.”
He estimated that raising the standard to 67 per cent would cost more than $12 billion over the next five years.
The new measures were expected to add about $700 million to bringing New Zealand’s earthquake prone buildings up to standard, on top of the $1b cost under the current rules.
Williamson said that 15 years for all assessments and strengthening was a “realistic timeframe” in the ministry’s view.
“We must ensure the earthquake-prone buildings system strikes an acceptable balance between protecting people from serious harm and managing the huge economic costs of strengthening or removing the most vulnerable buildings,” he said.
The cost to strengthen all earthquake prone buildings under the current system, which has a timeframe of 28 years, is $933m. It would be $1.68b under the ministry’s recommendation of 15 years.
“It’s a risk based calculation…what is the probability of this event occurring [again]?” Williamson said.
With some exceptions, the majority of buildings in Canterbury stood up well during the quake, he said.
“Look at Hotel Grand Chancellor, it did its job. It was completely munted…but nobody died.”
The commissioner’s report released today was the fourth of seven volumes.
A report on the investigation into the PGC building where 18 people died has already been released in earlier volumes, and the report into the CTV building where 115 people were killed, was delivered to the Governor-General last month and will be released on Monday.
Today’s report also makes recommendations for best practice, policy and legislation to help minimise the risks to public safety from vulnerable buildings during an earthquakes, but is not binding on the Government.
Most of those killed in the February quake, excluding those who died in the PGC or CTV buildings, were killed by falling debris when they were walking past a building, sitting in a vehicle outside a building, or had run out of a building to escape. Six people were in a neighbouring building when they were killed by falling walls or unreinforced masonry from another building and four people were killed by the building they were in.
Thirty six of the 42 deaths investigated in the report occurred within the CBD and the other six were in Christchurch suburbs.
All but one were caused by older unreinforced masonry buildings or brick or block structures.
Commercial property owners say the Government’s recommendations are on the right track, even though it will cost building owners greatly.
While the government estimates that up to 25,000 commercial buildings may need strengthening, at a cost of $1.7 billion, the Property Council believes the true number could be anywhere up to 40,000 buildings.
Council chief executive Connal Townsend said there would be relief the report was out.
‘‘It’s quite clear that thousands of buildings can’t be tidied up overnight...but it’s a lot greater certainly than there ever was under the old regime.’’
Public safety was paramount, but Townsend said members would be relieved that the proposals did not include raising the building code.
‘‘They’re zeroing in on the things that really matter."
However, the cost of upgrading would still be a struggle for many building owners and the Government had remained quiet on whether seismic work should receive assistance.
Ministers were still discussing the issue, Townsend said.
‘‘We’re concerned that the current tax system is actually artificially stacked against owners, and if anything it actually provides real genuine disincentives to owners to take action.’’
Finding enough skilled engineers to do seismic assessments would also be a problem, as the Christchurch rebuild and Auckland housing plan drew experts away from other centres.
One of the report’s ‘‘stark’’ revelations was that although Wellington did have many at-risk commercial buildings and apartments, Auckland had a larger number.
Whanganui’s high number of heritage buildings also made it an area of concern.
The council said it was noteworthy that the Government had only addressed commercial buildings, whereas the Royal Commission had wanted to toughen controls on residential housing as well.
- Local authorities should order assessments on all unreinforced masonry buildings within two years and all others within five years.
- Unreinforced masonry buildings to be strengthened or demolished within seven years from the enactment of the amendment and 15 years for others
- Threshold remains at 34 percent, but local authorities can order some buildings with high occupancy to comply with a higher standard
- Buildings which are “very seldom used” may be exempt
- The ministry should create a grading system, ranging from A to E, for buildings which is able to be understood by the general public.
- For unreinforced masonry buildings, chimneys, parapets and ornaments should be secured.
- The Building Act should be changed so local authorities can order residential building owners to address hazardous elements, such as unreinforced masonry chimneys, within a specified timeframe
- All non-residential and multi unit or storey residential buildings will have to have a seismic capacity assessment within five years of the changes taking effect, and be strengthened or demolished within 10 years after the assessment.
- Assessments would be faster for certain buildings on transport routes or which are identified as crucial in an emergency and some buildings, such as low-use rural churches or farm buildings would be given longer.
- Information on whether the building is below or above the earthquake-prone building threshold will be made available on a public register
- The current national earthquake prone threshold of 33 per cent will not be changed.
- © Fairfax NZ News
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