Comparison of seismic standards in Chile and Bay Area

February 28, 2010 12:00:00 AM PST
Chile has some of the highest seismic standards in the world. Still, it's estimated half a million homes were severely damaged or destroyed.

An internationally respected seismic engineer said Bay Area buildings would not hold up as well as the ones in Chile to an 8.8 earthquake -- here's why:

"They have strict regulations," said seismic engineer Eduardo Fierro.

Fierro says the majority of structures, in Chile, have an abundance of reinforced concrete sheer walls.

He showed a typical apartment building:

"They have six walls in the transverse directions and they have six walls in the longitudinal direction. That is a large amount of sheer walls that they have," said Fierro.

American buildings have fewer sheer walls. Pablo Valenzuela says even his modest childhood home, in Chile, was made of concrete and rebar.

"In my life over there, we had two major earthquakes and there wasn't even a crack in the house," said Valenzuela.

Many of the structures that collapsed in the capital city of Santiago were from the colonial era, or made of adobe. The emergence of strict building codes came after the 1960 earthquake which registered a magnitude 9.5 -- the largest ever recorded.

Santiago also has fewer soft story buildings. San Francisco and Oakland alone have an estimated 5,000 soft story buildings. Fierro says the engineers, in Chile, have more influence than the architects.

"In the U.S. you have to please the architect that wants open spaces and little columns and no walls," said Fierro.

Simply put, he says the Bay Area would suffer worse if an 8.8 magnitude earthquake struck here.

"Worse than what happened in Chile?" asked ABC7 Alan Wang.

"Much worse, I would say," said Fierro.

Fierro says he's seen an entire 10 story building torn down because it did not meet the strict codes in that country. Structural engineers and seismologists are now buzzing over this quake because it's showing them what worked and what didn't work under some of the worst earthquake conditions.


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