Rebuilding after this kind of devastation can take years. Many damaged buildings in earthquake zones are made of brick, with weak bracing. But there are ways of reinforcing these old structures to make them safer.
Five years ago a magnitude 7.4 earthquake destroyed much of Ismit, Turkey, killing more than 17,000. The high number of deaths was the result of inadequately reinforced buildings coming down on people.
Engineers have studied structures in the aftermath of these kinds of strong earthquakes to see how new and existing buildings can be made to withstand seismic forces.
In the U.S., strong structures begin with the enforcement of good building codes, something often lacking in the developing world.
Masonry without adequate bracing is the biggest problem for buildings when earthquakes occur. "There are several types, in general, that require strengthening," said Mr. Wallace. "The unreinforced masonry structures, this is basically a brick building that doesn't have any steel reinforcing in it."
But it is not practical to tear down and replace most of these inadequate buildings. Mr. Wallace adds, "Just because of the shear volume of the number of buildings is a very difficult economic reality to face. Every building is different and each requires it's own seismic solution. With each structure we really have to do some due diligence in evaluating what the strengths and weaknesses of the building are."
Jeff Rouze is a Los Angeles developer who is renovating an 87-year-old historic apartment building in Hollywood that suffered earthquake damage. "It had damage in the Northridge earthquake in 1994. This is a typical earthquake caused crack. This is a supporting beam for what they call a shear wall, which is a wall that would accept earthquake energy. And as you can see it's under stress and it's bowed. And we have had to reinforce it here until we can install a new beam overhead and some columns to transfer the load," he said.
The building requires new support beams and columns.
|Jeff Rouze, points out new reinforced wall|
Seismic resistant building adds cost, cost that poor countries find hard to meet. But the cost in lost lives from earthquakes is even greater.
... Payvand News - 2/25/05 ... --