Inspection reports call into question rapid-assessment placard system.
A system to determine the viability of buildings inthe immediate aftermath of earthquakes has been called into question following enquiries into the collapse of the Canterbury Television building in New Zealand that killed 115 people in February of this year.
That building had been damaged by a magnitude 7.0 quake in September 2010 but, despite the presence of visible cracks in the facade, it was passed as fit for occupation with a green sticker on the door. When a second quake hit on 22 February 2011, the building collapsed killing 115 people and accounting for almost two thirds of the 181 victims of that quake.
That tragedy has exposed shortcomings in a rapid assessment system that was pioneered in California and is used around the world to determine whether buildings can be reoccupied after major earthquakes.
Inspection reports obtained by The Associated Press under New Zealand public records laws show just how cursory the checks can be. They don’t take into account what predictably follows any major earthquake: aftershocks. Christchurch was hit repeatedly, as was northern Japan after its devastating earthquake and tsunami in March.
The problem is that people place more faith in the inspections than they should. A green sticker is no indication a building will withstand future quakes, nor does it require a robust analysis of a building’s structural health – something that was misunderstood by both building occupants and public officials in Christchurch.
The father of the system, Oakland-based structural engineer Ron Gallagher, said it’s often about triage, and officials sometimes make judgment calls based on instinct while trying to juggle assessments of hundreds of buildings. The responsibility for a full inspection, he added, lies with building owners.
On a visit to Christchurch after the February quake, Gallagher found problems. “We heard from a number of people that when the public viewed a green tag, they thought it meant the building was safe from future earthquakes,” he said. “That’s not the way the placard system is used, or is meant to be used.”
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