As seismic engineers study the earthquakes in Turkey and Syria that killed more than 20,000 people this week, it’s becoming clear that a significant cause of the destruction involved a building design common in California and other parts of the U.S.
The flaws of non-ductile concrete construction are found across the Golden State, with many buildings having not been evaluated or retrofitted and at risk of collapse in a serious earthquake.
It can be tempting for Californians to assume that their structures are inherently better than those in Turkey. But the state hasn’t been tested with a magnitude 7.8 earthquake in more than a century. And that event — the great 1906 earthquake — destroyed much of San Francisco.
It will take time for structural engineers to compile a comprehensive report on the damaged and destroyed buildings in Turkey and Syria. But several experts, looking at photos and videos of the pancaked structures, said the primary flaw is already obvious: They were non-ductile concrete buildings, which have an inadequate configuration of steel reinforcing bars that allows concrete to become brittle and explode out of the structure’s columns when shaken.
“The residential apartment buildings in the area are mostly made of brittle concrete and are extremely vulnerable to the shaking caused by earthquakes,” structural engineering firm Miyamoto International said in a statement.
Original Article from Los Angeles Times. Photo by LA Times.