InfrastructureBridge column withstands 6.9 quake in tests
Engineers in California test a bridge column design capable of withstanding a 6.9 quake; nearly all of California’s 2,194 state-owned bridges have been retrofitted better to withstand tremors; local cities and counties across California own 1,193 with work done on 729 of them
Engineers from across California were in San Diego on Monday to test a bridge column to make sure it can withstand a powerful earthquake. The engineers’ tests simulated a 6.9 quake against a column similar to those used in bridges built in the last fifteen years. For the tests, they used one of the largest outdoor shake tables in the world.
10News.com reports that nearly all of California’s 2,194 state-owned bridges have been retrofitted. Local cities and counties across California own 1,193 with work done on 729 of them.
Engineer Jose Restrepo said bridges that carry a heavy traffic load are up to code but the smaller bridges that are worrisome. “The small bridges that need to be retrofitted are not in populated areas of the state [such as] bridges that are in the desert with very little traffic,” said Restrepo.
The University of California San Diego is partnering with CalTrans to conduct the $500,000 tests. During the series of simulated quakes.
Restrepo said his team pushed the limits. “We want to take this column to near collapse,” said Restrepo. “It [would] be very unrealistic for CA, but we want to do it to get best idea.”
The shaking on the tests was modeled after the Loma Prieta earthquake in 1989 and the intensity was increased every time.
“What we need to make sure is that it does not snap,” said Restrepo. “Snapping is not what we want.”
Engineers said more testing is needed, but once the shaking is done, they will collect the data and compare it with other tests done in Japan and at UC Berkley. Engineers also said the column that was subjected to the tests performed well in the seismic vulnerability test.
