Tuesday, December 11, 2012

The Christchurch Earthquake Royal Commission report

The Royal Commission investigating several specific building issues around the February 2011 earthquake in Christchurch has reported back. And unsurprisingly, The Press devotes its editorial this morning to the report:

They are grim reading but the conclusions of the Royal Commission into the collapse of the CTV building are unsurprising. The hearings that guided the investigation were reported in detail, held the public's attention and pointed to faulty design as the cause of the disaster - a cause the commission has confirmed. But the lack of surprise does not lessen the shocking reality of the CTV collapse: 115 people killed in terrible circumstances, their families traumatised and forever scared, the deaths the result, largely, of appallingly poor design.
For the families, the commission's report provides a detailed account of the building's lethal failings, and it is such facts that can lessen grief. Some of the dreadful speculation that surrounds the deaths has been lessened, and more will be when the coroner reports. The families can thus start to deal with the emotion of their experience and not have to wonder about what exactly happened.
They, though, and the wider community, now need to bring into focus the business of ensuring the shonky consenting and design that doomed the CTV building does not happen again. It would be intolerable were New Zealand's inevitable future earthquakes made worse by deaths from ill-designed buildings. That is so obvious that moves are under way nationally to identify structures that have the weaknesses of the CTV and PGC buildings, the Government is considering the degree of strengthening required for buildings and local bodies are paying more attention to dangerous structures. But those welcome moves seem unco-ordinated with lack of clarity about the division of responsibility between the Government, councils and engineers and builders. It is the Government's job to clarify issues of responsibility, as it is to enforce the inspection procedures needed to certificate a build's quake-proofness, and to decide the quake-proofness required.
The CCC controversially wants buildings strengthened to 67 per cent, and is being challenged about that in court by the Insurance Council. The commission and the Government say the existing 34 per cent standard is sufficient. If uncertainty and legal proceedings are to be avoided, the Government will have to impose a standard.
Maurice Williamson, the Building and Construction Minister, clearly favours the lower standard, on the grounds that it provides a reasonable level of safety at an affordable cost. He parts company with the commission on its recommendation that unreinforced masonry buildings be assessed within two years and brought up to standard or demolished within seven. Williamson thinks the 15-year period recommended for most other buildings is sufficient. Unreinforced masonry buildings killed people in Christchurch and pose a risk throughout the country because significant numbers exist. Many New Zealanders would welcome their rapid strengthening or demolition, and the minister's lack of backing for that is already causing a backlash in Christchurch. That message is bound to come through in the four months that the recommendations are open for comment. It will increasingly be felt by landlords as their unreinforced properties lose popularity.
These disagreements are minor, though, in the context of New Zealand rapidly learning the tragic lessons of Christchurch and beginning to act on them.

It was not the Royal Commission's role to establish liability for the failure of the CTV building in particular. But a number of parties including the Christchurch City Council will be nervous at the Royal Commission's findings, and the subsequent referral to the Police for investigation of any criminal liability.

The CTV building seems to have been an tragedy waiting to happen. The Royal Commission has concluded that its design and construction in the late 1980's was inadequate, that strengthening work identified in 1990 and carried out in 1991 was insufficient, and that the engineer who inspected the building after the September 2010 earthquake was unaware of its shortcomings, and unable to get access to detailed plans.

The Christchurch City Council will be especially nervous. The report has concluded that the CTV building ought never have been consented. There is now a real issue of both civil and criminal liability for the CCC based on the Royal Commission's conclusions.

The Government has accepted the report from the Royal Commission, and will now take advice on how to proceed from this point. That ought not be done in haste; as the Press notes, much of the report is highly technical in detail, and expert input will be required.

Lastly, our thoughts and prayers are with the families of those who were killed in the CTV and PGG buildings. The release of the Royal Commission's report will have reopened old wounds for many. We hope that the report, and the Government's response to it will be important steps in the quest for closure and peace.

1 comment:

Ciaron said...

I have to say, I just cringe when I hear this absurd term "quake proof" you cannot make a building "quake proof" because, to do so you need to know in advance the lateral and vertical accelerations, cycles & duration the building will be subjected to during it's operational life. Now, to do this you really need a talent for crystal ball gazing, which sadly, they don't teach you when doing your degree or diploma in engineering.

So what we have is the next best thing: a design event. Given known parameters and historic seismic activity, we look at what kind of event can be reasonably expected during a building's operational event and design accordingly. Due to various assumptions made on the reliable strength of materials, practicality of construction and other contributing factors, most designs are in fact quite conservative, resulting in building strength somewhat above what is required by the code.

What people MUST bear in mind and in some cases comprehend, is that if a building experiences shaking that significantly exceeds the design event, a range of failures is to be expected. local phenomena such as soil conditions and building form (natural frequency etc.) will also be contributing factors.

In short, "quake proof" is an utterly useless and misleading term.