LOS ANGELES (CBSLA.com) — The dramatic collapse of a heavily-traveled bridge in Washington state has raised questions about the safety of bridges in Southern California.
KNX 1070′s Margaret Carrero reports some of the region’s aging structures face increased scrutiny following the bridge collapse that sent two cars into the water, but miraculously, left only three people injured.
On Thursday, a truck hauling an oversized load hit the overhead girder of a bridge on a major thoroughfare between Seattle and Canada, sending a section of the span and two vehicles into the Skagit River.
While initially the cause of the collapse was unclear, authorities now believe the too-tall cargo hit an upper part of the four-lane Interstate 5 bridge near Mount Vernon, about 60 miles north of Seattle.
The bridge had been classified by a Federal Highway Administration database as being “functionally obsolete,” which is the same classification given to a span of the Santa Monica (10) Freeway near the 110 Freeway in a 2011 study.
Safety concerns have also been raised about other bridges in the Southland, including the Commodore Schuyler F. Helms drawbridge in Long Beach and the East Fork Road bridge over the San Gabriel River.
The Helms bridge is currently being replaced, but engineers say the process could take years to complete.
A 2009 report by Transportation for America, a public policy coalition, concluded that 12.8 percent of bridges statewide are rated “structurally deficient” according to government standards.
Dr. Navid Nastar, an engineering professor at the University of Southern California, said it could be a variety of factors that are ultimately responsible for compromising a bridge’s structural integrity.
“Keep in mind, when the impact happens, usually the weak points of the bridge…are more susceptible to showing failure and eventually leading to the whole bridge collapsing,” Nastar told CBS2.
Professor James Moore, the vice dean of the USC Viterbi School of Engineering, said the state has done a good job of finding the structures in most need of retrofitting and finding economical ways to get the job done.
“What really comforts me is California is one of the few states to really invest resources in the fundamental question: ‘Given that I can’t do everything, how do I prioritize?’” he said.
Moore also said that catastrophic events, such as the 1994 Northridge quake, helped make the state a safer place.
“I think that these sorts of events do have an upside. After the Northridge earthquake, I took a close look at what Caltrans had done in terms of the choices it made about retrofit and I’ve come away very impressed with what Caltrans has done locally and on the state level,” he said.
Some Southland drivers, however, think it’s time for public officials to take charge of the region’s roadways.
“Sometimes I just drive past these bridges and I don’t even think about it,” said one man.
“They probably all need to be reinforced by now,” another driver said.
Last August, an investigation into safety testing practices used on Northern California bridges raised questions amid alleged improprieties involving at least one Caltrans safety inspector.