BAY AREA QUAKE : Caltrans to Inspect Bridges and Overpasses in L.A. Area

California Department of Transportation officials announced Wednesday that they are organizing two teams of engineers to assess the seismic safety of overpasses and bridges in the Los Angeles area, including the Harbor Freeway transitway now in the early stages of construction.

James E. Roberts, chief of Caltrans’ structure division, said one team will concentrate on new construction in the Los Angeles area. He said the second team will review the design plans on older structures bearing a similarity to the mile-long section of the Nimitz Freeway in Oakland that collapsed in last week’s earthquake.

Of prime concern to the engineers, Roberts said, will be the double-decked portions of the Interstate 10 approaches to the Los Angeles River bridge near downtown and a two-mile section of the Harbor Freeway transitway that will be elevated.

Although state engineers say they are still looking at possible causes of the Nimitz collapse, its failure has forced them to focus new attention on double-decked, multicolumned freeways. Several University of California engineers have said that joints in the Nimitz columns gave way, causing support columns to fail and the upper deck of the freeway to collapse on the lower deck, killing at least 39 people.

Roberts insisted repeatedly that officials believe that Los Angeles bridges and overpasses would not collapse in an earthquake but added that they wanted to conduct the additional inspections to allay any fears local residents may have.

“There’s a concern obviously in Los Angeles, and so they’ve asked us to come down and reassure them and that’s what we intend to do,” he said. “We know we have to build peoples’ confidence again.”

Caltrans Regional Director Jerry Baxter told the Los Angeles City Council Tuesday that he had asked that experts be appointed to inspect the Harbor Freeway construction for seismic safety in light of the collapse of the Nimitz Freeway.

Caltrans spokesman Jim Drago said a team of eight engineers will travel to Los Angeles for on-site inspections of new construction and their design plans. He said the team will include four Caltrans bridge engineers, with a combined experience in designing bridges of nearly 100 years, and four private consulting engineers, with expertise in the fields of seismic research and structural design.

“They’re going to look at the plans for any new structures in the Los Angles area that involve any sort of an elevated highway,” Drago said.

He said the second team will work out of Sacramento reviewing the design plans of older, existing elevated structures in the Los Angeles area, with particular emphasis on those that are double-decked and multicolumned.

He said the team will look at structures built before 1971 for any design features similar to the section of the Nimitz Freeway that failed.

“We’re not doing this because we think there’s a problem. We’re doing this to be cautious and make sure there isn’t a problem,” he said.

Roberts said the portions of Interstate 10 at the Los Angeles River will get attention first because those structures are more like the Nimitz Freeway than any other in the area.

Even so, he said he believes that there is enough difference in the design of the two structures to make the Interstate 10 bridges safe in an earthquake. The Interstate 10 approaches, for example, were built much later than the Nimitz Freeway and include much more steel and less concrete in their construction.

By the same token, he said, the new Harbor Freeway construction will be built according to a design that is considered state-of-the-art for seismic safety.

The following Times staff members contributed to earthquake coverage. In Oakland: Stephanie Chavez, Ashley Dunn, George Ramos and Ronald L. Soble. In San Francisco: Larry Green, Charisse Jones, Norma Kaufman, Suzette Parmley, Tracy Wilkinson and Victor F. Zonana. In Santa Cruz: Charles Hillinger. In Los Angeles: Kristen Christopher, Cathleen Decker, Myrna Oliver and Bob Secter.