Making an expensive judgment call

Last updated 12:58 30/04/2014
Trafalgar Centre.
MARTIN DE RUYTER/FAIRFAX NZ
OUT OF BOUNDS: Question marks remain over the closure of the Trafalgar Centre.

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As the debate over the closure of the region's main indoor venue continues, Kate Davidson looks at the earthquake risk issues faced by councils throughout the country.

What is an acceptable level of risk to human life, and how can this be managed? These are questions councils around New Zealand must ask themselves when dealing with buildings at risk of earthquake damage.

Nelson city felt the impact of this question with the city council's decision to close the Trafalgar Centre last December.

The move has been questioned, with former councillor Kerry Neal leading a group calling for the centre to be reopened. It says the council made the decision based on incorrect information, especially regarding the depth of the building's piles.

Senior structural engineer and director of Centraus Structural Consulting, Michael King, says the council made the right decision, but he describes the estimated $27 million repair cost as "silly".

King, who has worked in post-quake California, Haiti and Christchurch, travelled north to speak to the council free of charge. He says his mission is to make complicated engineering-speak understandable to those receiving it.

"They did what they thought they had to do, and I totally agree with their rationale."

He uses basic analogies to explain the dilemma facing councils.

"If it was your child being put in that building as it was, would you be comfortable to say, ‘I want my child in there'? That's what council have to do."

He points out that people take risks every day, employing precautions as they drive, walk and cycle, but there is always potential for harm or death.

"You could be hurt tomorrow or drive for 30 years and never be hurt - that's the same thing with buildings."

However, there is always the question of how much risk people are willing to accept. King says the council made a reasonable and prudent decision in this regard.

"It's a difficult situation to be put in, because they are not engineers."

Nelson Mayor Rachel Reese says all the professional advice the council received was that the risk of loss of life or serious injury in the Trafalgar Centre was at a point where the building had to be closed until that risk was reduced.

The weakness lies with the northern wall, which everybody has to pass through to enter and exit the building.

"It needs to be closed, because the point at which you have to get a whole lot of people out of the building is the point where it is most likely to collapse."

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It might be a very different situation if the weakness was not at the exit point, she says.

The decision to close the building was based on the best evidence at the time the decision had to be made, but if other evidence comes to light and the risk is reduced, then the decision could be amended, Reese says.

She says the council did not want to close the centre right before Christmas, but there was no other information that came forward to say it should stay open.

The Building Act 2004 gave local governments the authority to define their policies for how they manage earthquake-prone buildings.

Local Government New Zealand president Lawrence Yule says that despite different policies, he would expect different councils to arrive at the same decision when looking at a particular building.

Reese does not believe the council's decision was out of kilter with good practice.

"It always depends on who is sitting around the table and the information received, and we make a judgment call on the information we receive," she says.

"In terms of the decision-making process, if the information we had was placed in front of another council, I think the decision would have been most likely to close."

She points out that the Hastings District Council closed the Hawkes' Bay Opera House in March after it received an adverse engineering report.

Reese says councils are liable for their decisions, which are not taken lightly.

"We are sitting in governance roles, like the board of directors of a company, and if we knowingly have a risk and are allowing that risk to continue, then we should be held liable.

"Once you know, you can't pretend you don't know."

Advice from engineers, lawyers, and council staff was that the building needed to be closed, she says.

Councillors could not then say, ‘Oh no, the public is going to be upset about that, we won't do it', because if the building failed and people were killed, the council would be in front of a Royal Commission with nowhere to go.

"[The] community will then say, ‘How did you ever make that decision, faced with all of that evidence? How could you possibly let people go into that building that killed them?'."

King says the engineering reports so far show that the Trafalgar Centre is "not that bad". He told the council that the proposed $27m cost of repairs was scary and silly.

"I don't see that anything could cost that much to fix that building up.

"They are not going to get a new building out of it, but they have what they've got, and they want to make it better and reduce the risk to people - which is fantastic. That's what they should do."

He advised the council to bring in different engineers and hold a workshop with them to try to find a solution that suits the region's needs.

"There are no straightforward answers. It's not like when your car is broken and you know what to fix."

It's about finding what's best for the council, for Nelson, and for those who use the building, he says.

Other councils are facing similar issues.

Wellington City Council seismic assessments manager Steve Cody says Wellington has left yellow-stickered buildings open with signs letting the public know of the structure's condition, as it is about "personal choice". However, some buildings have been closed.

The Christchurch City Council this year changed its position on closing all buildings that fail to meet 34 per cent of the Building Code.

Under a new policy, the council has reopened some previously closed buildings with signs stating that they are below 34 per cent but have been assessed by engineers as fit to occupy.

All buildings without "significant damage" and with no threat of any part collapsing can be occupied. Buildings with significant damage, which puts them under the 34 per cent mark, should not be.

The council is setting up a specialist engineering panel to advise on the occupancy of council-owned buildings with ratings below 34 per cent, which have the potential for partial or full collapse.

"Buildings that fit into this category but are deemed fit to occupy by the engineering panel will also remain open," says community services general manager Michael Aitken.

Cody says that under normal circumstances, a number of Wellington buildings are not dangerous - they will only become dangerous during an earthquake.

Many Wellington buildings proved themselves during last year's Seddon earthquakes, which also shook the capital.

Cody and King say every building is unique, and a lot of things have to be considered.

Reese agrees, saying each case is unique and a number of factors have to be taken into account, including a range of regulations and laws.

King does not believe New Zealand is being too risk-averse. He points out that what is happening here now happened in California following a 1994 earthquake.

The ground moving rattled people's sense of security and assurance, as solid ground "dances like the ocean in a storm", and it took time for people to come back to normality and find an equilibrium, he says.

"At some point, things will calm down and there will be a new way of looking at things, and it will have this experience ingrained in the new way of looking at it."

One size fits all?

nconsistent policies on earthquake-prone buildings are to get a shake-up, with a new bill making its way through Parliament, but Local Government New Zealand is opposed to what it sees as a "one size fits all" approach that does not take into account the unique situation of each local authority.

However, engineer Michael King says it is the "nature of the beast" to have such a system after a big event such as the Canterbury quakes.

The Building Amendment Bill passed its first reading in March, and is a result of earthquake-prone buildings not being "managed in a consistent, timely and cost-effective way", with the current system "not achieving an acceptable level of risk in terms of protecting people from serious harm in moderate earthquakes".

A national time frame of 20 years will be set for buildings to be strengthened or demolished. Local authorities will have five years to assess all buildings, and work will have to be completed on them within 15 years of the assessment.

It will also allow councils to issue building consents for required work on earthquake-prone buildings without requiring other upgrades in certain circumstances.

Building and Construction Minister Maurice Williamson says the bill will "ensure earthquake-prone buildings are dealt with in a timely manner by way of a nationally consistent system".

"It strikes a balance between protecting people from harm in an earthquake and managing the costs of strengthening or removing such buildings.

Under the changes, central government will have "a greater role in providing leadership and direction in relation to earthquake-prone buildings".

However, Nelson Mayor Rachel Reese says that while there are advantages in having consistency, the new law will be much harder on some places than others.

Rural communities in particular could be hit hard financially and socially if they have to close core community buildings, she says.

"I think one of the things we have to think about as a country is not to overreact and become a risk-averse nation, so we have to mange the risk in a way our communities are comfortable with."

- Nelson

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