Demolition experts say one of the lessons learned in the ongoing recovery efforts after the 2011 earthquake in Christchurch, New Zealand, is that contractors should have more involvement in emergency preparedness.
Meeting on March 23-26 in San Diego—in a state that potentially has much to learn from the New Zealand experience—the National Demolition Association (NDA) released a six-point guide to improve disaster recovery and preparedness. "There were a lot of good takeaways that we can apply in California," says Stephen Sellers, assistant secretary with the California Emergency Management Agency.
However, NDA representatives questioned whether governments in disaster-prone areas are fully prepared. "There is no doubt in my mind that a major earthquake in a highly urbanized area will be the ultimate test for any city, state or the U.S. government," says Mark Loizeaux, president of Phoenix, Md.-based Controlled Demolition Inc.
While Christchurch experienced a magnitude-6.3 quake, relatively low on the Richter scale, its shallow depth and the area's sandy soil led to the second-highest level of peak ground acceleration ever recorded, second only to the 2011 quake in Fukushima, Japan.
"I was not prepared for what I saw in Christchurch," says John Weber, retired president of ICONCO/LVI Demolitions Services, Oakland. In March 2011, Weber was part of a team assembled by the U.S. Army Corps of Engineers to assist the New Zealand government with recovery. Christchurch was virtually shut down. The entire central business district of 1,000 city blocks was fenced off and restricted, he says.
While 1,200 commercial buildings have been demolished to date, a large chunk of the central business district is still off-limits and several hundred more commercial buildings and thousands of residences wait to be demolished.
Much of the city's paralysis over the past two years could have been reduced through better demolition planning, Weber believes. Main city thoroughfares remained closed for months because nearby buildings waited for demolition. "You can't pick and choose a building here and there and not do them all because you can't open the street until all the imminent danger is gone," he says. To minimize post-disaster arguments, the association recommends that communities plan which major arterial roadways should be cleared of dangerous structures first.
After the quake, a flood of inexperienced demolition contractors caused other problems. "When we started out, there were only a handful of demo contractors in the city," says Peter Ward, managing director with Auckland, New Zealand-based Ward Demolition Co., the firm responsible for demolishing the highly unstable 26-story Hotel Grand Chancellor. Now, there are at least 160 registered with the city, he says. "Anybody who had a digger, ever thought about demolition or knew how to spell the word became competition," Ward says.
NDA President Jeff Kroaker says the group needs to rekindle efforts to make sure demolition contractors are prequalified and that their types of equipment and services are made known to local disaster planners. Other measures include establishing a way to deal with violators and a clear indication of which agency will let contracts.
An inventory of building heights and area cranes—as well as the cranes' reach capacity—can help speed immediate rescue efforts, the association advises.