Two years after a 6.3 magnitude earthquake struck the Christchurch, New Zealand, the city of 400,000 is still cleaning up from the devastation. Three demolition contractors who were on the ground in the months following the earthquake shared their experiences at the 40th National Demolition Association (NDA) Convention in San Diego in late March.
John Weber, former president of Iconco/LVI Demolition Services, New York, and L. Mark Loizeaux, president of Controlled Demolition, Phoenix, Md., were both part of a team assembled by the U.S. Army Corp of Engineers that traveled to Christchurch in March 2011 to provide advice and assistance to the New Zealand government on how they could develop and implement the orderly demolition of structures and reoccupation of the city.
Weber told the audience he has participated in the cleanup of earthquakes in Los Angeles; Seattle; Anchorage, Alaska; and the San Francisco Bay area, but he said, “I was not prepared for what I saw in Christchurch.”
He describes the city in the aftermath of the February 2011 quake as “virtually shut down and paralyzed.”
“The entire central business district of approximately 1,000 city blocks was fences off and restricted to government personnel or crews of contractors,” described Weber. The area is referred to as “ the red zone” and two years later, there is still a portion of the red zone left that is fenced off to the public.
Some of the buildings were still standing following the earthquake but had sustained serious damage. This included the 27-story Grand Chancellor Hotel which Weber said was leaning so badly that engineers had to had to pour a massive concrete footing to prevent it from tipping over and causing damage to other buildings during the aftershocks.
Over 1,200 buildings have been demolished and several hundred more have yet to come down, said Weber. Several hundred residences may also have to be demolished. Weber also noted that after the earthquake liquefaction created a sea of silty, mucky sand everywhere he looked.
Weber said he asked himself, “How could a 6.3 magnitude earthquake do this much damage to a modern high-rise city?”
The answer in part, he said is PGA or peak ground acceleration, which is defined as how fast a portion of ground is moving compared to the ground around it. The PGA in Christchurch on Feb. 22, 2011 was one of the highest ever recorded, according to Weber only surpassed by the earthquake in Japan one month later.
Peter Ward, president of Ward Demolition, Auckland, New Zealand, also responded to the quake. He explained how a card system was used to let demolition contractors know what buildings needed to be demolished. A red card indicated demolition was needed. Yellow meant to exercise caution and green meant the structure was safe to enter.
He also recalled that 185 people lost their lives in the CTV building. “We pulled far too many bodies out of that building,” he said. “Christchurch was beautiful. We’ve lost our heritage. We’ve lost our city.”
Ward talked about some of the issues that emerged from the high number of buildings needing to be demolished. He estimated that about 160 to 300 contractors were performing work in Christchurch. When a house would need demolished 60-70 contractors would bid on it. There were also issues with insurance companies not paying out.
Controlled Demolition’s Loizeaux remarked that there was “a lot to learn about how much we didn’t know,” when it came to how the cleanup of Christchurch had been handled. One way to learn the lessons, he contended was to bring attention to the problems. He also gave the following recommendations to handle the cleanup from an earthquake:
- Have a response plan in place.
- Have a single person in charge.
- Legal and political authority to act.
- The person or entity in charge has the funds to act and the authority to disperse them.
- The person or entity communicates often and well.
- The political support for the person or entity must not waiver.
Loizeaux ended his presentation by asking several questions of the audience about their communities’ preparedness for a major earthquake. After the session a press conference was held at which time, newly named NDA President Jeff Kroeker, Kroeker Inc., Fresno, Calif., said the NDA would put together a committee to approach government officials with a solid plan for how the demolition community would respond to a major earthquake or other disaster.
The 40th Annual NDA Convention was March 24-26 in San Diego.