Freeway May Be Closed for Monday Commute

The three-mile section of the Hollywood Freeway that was closed Friday because of the subway tunnel fire will not be reopened this weekend and might not be open for the Monday morning commute, California Highway Patrol officials said.

A 150-foot section of the roof over the stricken tunnel collapsed to within 10 feet of the freeway, and officials are concerned that heat from the fire might have weakened the 18- to 20-foot-thick wall of soil directly between the tunnel and the freeway.

Jerry Baxter, head of the state Department of Transportation district encompassing Los Angeles, said the agency would not be able to make any decisions about reopening the freeway until civil engineers were able to enter the tunnel and assess the strength of the soil above it. The fire directly under the freeway was extinguished Friday afternoon, but engineers were driven back by the heat when they attempted to enter the tunnel.

According to Los Angeles Fire Marshal Dave Parsons, engineers were planning to enter the tunnel Friday evening, if it had cooled sufficiently, to begin shoring it up with a timber frame. By mid-evening, however, the tunnel was still too hot for a thorough inspection.

If the freeway segment remains closed Monday or later, it is expected to create problems for commuters because the route, U.S. 101, is the main artery linking downtown Los Angeles to Hollywood, the San Fernando Valley and Orange County.

The El Monte busway that runs adjacent to the Hollywood Freeway in that section will most likely be reopened by Monday, according to Dave Roper, deputy district director of Caltrans. The busway is 50 feet above the ground and officials are not particularly worried about its structural integrity.

They did not reopen it immediately, however, because they feared that vibrations from traffic would be transmitted through the soil and cause more of the tunnel to collapse. It will not be reopened, Roper said, until the tunnel is shored up with timber.

Engineers reported being concerned about the safety of the freeway because it is not built on bedrock in that area. Rather, it is supported by compacted earth and sand that have been injected with cement-like grouting for bonding. The bonded material is not as strong as either concrete or rock, and engineers feared that the bonding may have been weakened by the intense heat from the flames.

Temperatures inside the tunnel reached about 1,800 degrees Fahrenheit.

The tunnel roof that collapsed had not been reinforced with grouting because there were no structures above it.

Engineers took some of the bonded material--from a section that had not been affected by heat--to a laboratory where they planned to heat it and measure the loss of strength, if any. If that test shows little effect from the heat, Caltrans officials expressed more confidence about reopening the freeway quickly.

Civil engineer Ed Kavazanjian of Earth Technologies Inc. in Los Angeles said that engineers have had little experience with the effects of heat on the grouting, but that “most likely” it would not be damaged by the heat.

But the reopening date will not be determined, experts said, until engineers can get inside and inspect the tunnel.

Once inside, they will be looking for any evidence of settling, which would be an immediate indication that the safety of the freeway is threatened. If no visible evidence of danger appears, they are expected to bore holes into the compacted material to assess its strength and to remove samples for testing.

The freeway itself is almost certainly not damaged, officials said, because of the insulating properties of the soil between it and the tunnel.

METRO RAIL’S TROUBLED HISTORY September, 1986--The Southern California Rapid Transit District begins construction. January, 1987--Problems related to contaminated ground water and land acquisition delay construction for almost six months and raise cost $3 million to $5 million. January, 1988--Discovery of contaminated soil at Union Station, apparently left behind by old coal gasification and synthetic rubber plants, forces realignment and delays construction nine more months. July, 1988--Six members of a DWP work team are injured in an underground explosion. The team was trying to reconnect a 4,800-volt line shut down temporarily for Metro Rail construction. July, 1988--An 83-year-old man who had walked away from a retirement home falls into a 23-foot-deep excavation at a Metro Rail site on 7th Street downtown. August, 1988--An underground fiber-optic line is accidentally cut by a Metro Rail construction crew at 1st and Hill streets. Automatic bank teller machines and Inter-Track wagering at Santa Anita Race Track, and other services connected to Pacific Bell data lines, are affected. May, 1989--Two Metro Rail construction workers are slightly injured when part of a tunnel-digging machine collapses. June, 1989--One worker suffers smoke inhalation in a fire at a Metro Rail construction site beneath 1st and Hill streets. The fire began when an electric arc welder came into contact with wood and plastic. July, 1989--Dispute over soils data and RTD’s construction plans causes a contractor to threaten a work stoppage and ends up costing the RTD an additional $800,000. September, 1989--An audit report reveals millions of dollars in Metro Rail funds had not been accurately accounted for by RTD bookkeepers and managers. October, 1989--Two Metro Rail workers are injured when a cable snaps as a construction locomotive hauls a piece of digging equipment. March, 1990--Los Angeles city firefighters rescue a Metro Rail worker who slipped and fell in a subway tunnel. April, 1990--Two underground workers are slightly injured when a rubber cement chute breaks and hits them at 5th and Hill streets. May, 1990--State Court of Appeal rules it is unconstitutional for RTD to have commercial property owners pay part of the construction costs for the first leg of the $3.6-billion subway. Compiled by Times researchers Tom Lutgen and Cecilia Rasmussen