Double-Deck Road Safety Stirs Debate

Seismic experts and California transportation officials were sharply divided Wednesday over whether the state possessed the know-how to bolster the Nimitz Freeway in Oakland against an earthquake of the magnitude that caused a double-decked section of the roadway to collapse.

Several seismic engineers argued that studies of structure failure after the 1971 Sylmar earthquake provided the insight for the state to make necessary improvements on older highways like the Nimitz.

“The technology does exist. It’s simply a matter of money,” said John Kariotis, a structural engineer based in South Pasadena who is known around the country for his work on seismic safety.

The controversy centers on the multiple columns that supported the freeway and which gave way during the earthquake. Kariotis and others contend that older freeways like the Nimitz, which was built in the early 1950s, can be substantially strengthened by wrapping the vertical columns with extra steel and then jacketing them with an extra layer of concrete.

The problem in Oakland was exacerbated by the landfill on which the roadway is built, he said. The similar double-decked Embarcadero Freeway on the San Francisco side of the bay appeared to have weathered the quake without a collapse because it is on more solid ground, he said.

The 1971 earthquake centered in Sylmar taught the California Department of Transportation the need for reinforcing the connections between elevated spans of roadway, according to Kariotis. Subsequent quake experience and research should have alerted officials to the possible weakness of the columns under elevated roads and bridges, he said. Yet the state did not do enough on that, he said.

But William E. Schaefer, chief engineer for Caltrans, said that wrapping the columns was not a technique proven effective on freeways with the column configuration of the Nimitz.

“We really don’t have the expertise to know what to do to fix these,” Schaefer said. He added, “We don’t have the technical knowledge, nor does it exist anywhere in the world.”

Schaefer said that research is under way at UC San Diego on the best way to retrofit an elevated freeway like the portion of the Nimitz that collapsed, but it will take at least a year to find a solution.

Moreover, Schaefer said that the lessons learned from Sylmar were applied to the Nimitz. He said that the portion that collapsed had been “retrofitted.” But he said the work that was done only solved the problem of the kind of lateral movement that caused freeway decks to slip off their supports, as they did in the 1971 quake.

About $110 million in federal money has been spent in California in the last 15 years or so as part of a project to seismically strengthen the state’s bridges and highways, according to David W. Frederickson, a spokesman for the U.S. Department of Transportation in Washington.

Frederickson said another $64 million has been earmarked for a second phase, and that phase will involve wrapping the bases of elevated freeways that are supported by single columns, according to Schaefer. He described the Nimitz as a multicolumn freeway.

Among a number of structural engineers, the collapse of the Nimitz along with partial failure of the San Francisco-Oakland Bay Bridge and the severe damage to buildings in San Francisco’s Marina District have aroused more indignation than surprise.

“There were no real surprises . . . no new lessons there, not from this earthquake, none at all.” said Peter Yanev, chairman of EQE Engineering Inc. of San Francisco, a large earthquake engineering consulting firm.

Yanev and others interviewed Wednesday said that state transportation officials have known for years that roads and bridges such as the Nimitz Freeway and the Bay Bridge built before the 1971 Sylmar quake were not as strong as they should be.

“That we have known these things for years and had no concerted push to do something is tragic,” Yanev said after viewing much of the devastation in the Bay Area on Wednesday.

Frank Baron, a retired professor of civil engineering at UC Berkeley, where he taught for 29 years, said that the number of studies on structural failure after the Sylmar quake gave officials the ability to make necessary repairs on older highways and bridges in the state.

“They (state officials) have had sufficient knowledge from the studies to do the remedial retrofitting to ensure that severe damage did not occur,” Baron said.

“The lesson that (Sylmar) taught us was very important. We were not giving enough strength to the piers (columns) of certain freeways, nor sufficient support to the decks,” said Vitelmo Bertero, director of the Earthquake Engineering Research Center at Berkeley.

Bertero is heading a team of structural engineers assigned to survey damage and prepare a report for the Earthquake Engineering Research Institute in El Cerrito.

After examining the Nimitz Freeway Wednesday, Bertero said it was clear that the piers lacked crucial lateral reinforcement.

“There are probably no new lessons to be learned from this earthquake. It just re-emphasizes the old lessons that we haven’t paid attention to,” Bertero said.

As for San Francisco’s Marina District, a well-to-do neighborhood built on soft soil, Bertero said: “I have been preaching for a long time against building on filled land. If it (the area) is rebuilt, it should be done only on special foundations that are very expensive.”

Tim Tobin, a spokesman for the California Seismic Safety Commission, said it is going to take at least five years to replace the overpass section of the Nimitz that collapsed. This will be “a major, major disruption in traffic patterns and highway infrastructure. There will be a fairly significant number of lawsuits in terms of culpability. I’m not trying to paint it too bleak; I’m taking a realistic look at everything. This is another grim reminder of the lessons we should have learned from Mexico City and Whittier. This only confirms what we’ve already known.”

After surveying the damage in San Francisco, Tobin said, “When I see this, it’s terribly sad. I stood on a street corner in Armenia during the quake at a school site where 600 kids died and all you could have done was cried. I get very angry when I see the damage in San Francisco. The government and engineers just have not done what needs to be done. What does it have to take? California has got to face this earthquake problem.”

At a meeting of the state Transportation Commission in Sacramento on Wednesday, Commissioner Stanley W. Hullett predicted the Bay Area’s “economy is going to come to a standstill” because of the highway problems triggered by the earthquake.

“It’s well known we have no money left in the pot with which to build highways, much less fix these highways,” Hullett said. “We’re going to be in difficult straits in order to be able to find the money.”

The Nimitz disaster has struck a blow to plans in Los Angeles to double-deck much of the area freeway system.

Los Angeles County Supervisor Kenneth Hahn on Wednesday called for a halt to the double-decking now under way on the Harbor Freeway that runs through downtown Los Angeles. Assemblyman Richard Katz, a Sylmar Democrat and chairman of the Assembly Transportation Committee, said that the Nimitz collapse “raises legitimate questions about double-decking of freeways.”

However, structural engineer Kariotis stressed that there is nothing inherently dangerous with the concept of double-decked roads, like the one proposed over portions of the Harbor Freeway, if they are built to new standards.

Times staff writers Larry Gordon in Los Angeles, Doug Frantz and Sam Fulwood III in Washington, Ed Iwata in San Francisco and Mark Gladstone in Sacramento contributed to this story.