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MINNEAPOLIS BRIDGE DISASTER: CALIFORNIA ASSESSES RISKS

Caltrans to inspect bridges

Thousands need to be repaired or replaced, federal records say.

August 03, 2007|Sharon Bernstein and Catherine Saillant | Times Staff Writers

Caltrans officials on Thursday began emergency structural inspections of 69 bridges across California in the wake of the collapse of a span in Minnesota.

Many of those bridges are among nearly 3,000 in the state that the federal government found to be structurally deficient, with inspectors concluding that they must be repaired or replaced.

State transportation officials said Thursday that the federal findings don't mean the bridges are unsafe for vehicle use. Routine inspections have found all spans to be structurally sound, they said.

"If we felt that a bridge was unsafe, we would close it immediately," said Doug Failing, director of the California Department of Transportation's Los Angeles and Ventura County operations.

Caltrans Director Will Kempton said the state plans to inspect the 69 bridges built with steel trusses similar to those that failed in the Minnesota accident. The state owns 22 of those, and city and county governments own the rest.

The failure of the Minnesota bridge -- which was also classified by the federal government as "structurally deficient" -- has sparked concerns about whether other bridges are in danger of collapsing.

The U.S. Bureau of Transportation Statistics, which catalogs federal highway and bridge data provided by the states annually, reported problems with about 6,700 bridges in California. Those include steel-truss bridges as well as other types of spans. Of those, 2,994 were considered structurally deficient, needing "significant maintenance attention, rehabilitation or replacement."

The others were found to be "functionally obsolete," because the spans weren't built to handle today's traffic loads. Federal officials found these bridges in many cases were too narrow or didn't have proper vertical clearance.

About half of the roughly 24,000 bridges in California are owned by the state, and the rest are owned by city and county governments. Of the bridges found to be deficient, about half are owned by the state.

Most of the bridges owned by the state had problems with their surfaces, which officials insisted late Thursday were not critical flaws.

But 63 of those state-owned spans, including 27 in Southern California, had more significant structural problems, according to state records. Detailed data were not available on bridges owned by county and local governments.

State-owned spans in Los Angeles County with structural problems include the Commodore Schuyler L. Heim Bridge in Long Beach, a stretch of Kanan Road at the 101 Freeway, and the 405 Freeway at Temple Avenue.

In Riverside County, several spans were also structurally vulnerable, including Indian Street at the 15 Freeway and Warm Springs Creek at the 15. Structural problems in Santa Barbara County included Santa Monica Canyon at Highway 192, and the 101 Freeway at Oak Creek.

The state's bridges are relatively old -- half were built before 1967. And many are carrying trucks and other vehicles that are much heavier than the ones for which they were designed, causing stresses and crumbling concrete. The Gerald Desmond Bridge in Long Beach -- which has become an important route for port truck traffic -- is wrapped in wire nets that keep chunks of concrete from falling into the water and onto the streets below.

Failing and other Caltrans officials argued that bridges in California are safer than those in other states because most are built to withstand earthquakes.

And unlike bridges in other states, he and others said, bridges in California are built to withstand stresses in several places throughout their structure, so that if one support or joint is damaged by a quake, the others would continue to hold up the span.

But some other engineers said the state should be doing more -- not just inspecting bridges but also moving to fix the thousands that the federal government said are deficient.

"They're taking a whack-a-mole response to these things," said Richard Little, who heads USC's Keston Institute for Public Finance and Infrastructure Policy.

Little said the state should be concerned about the federal findings. "The public isn't interested in whether we have good bureaucratic procedures in place," he said. "The public is concerned whether we have public agencies that are on top of things."

Chia-Ming Uang, a structural engineering professor at UC San Diego, said that inspections are particularly important in assessing the safety of older bridges.

Many older bridges -- including several hundred in California -- are made of steel, Uang said, and can fail as the metal becomes fatigued. Prompt inspection of such bridges, which are more common in the eastern part of the country, is required to determine if there are cracks in the structure.

In addition to the issue of structural integrity, California has had to grapple with the danger posed to bridges by earthquakes.

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