The infant Century Freeway apparently has passed its first tremor test with flying colors, Caltrans officials said.
A preliminary inspection of the 3-month-old freeway found no stress cracks or other damage after Monday's magnitude 6.6 earthquake. The 105 Freeway has some of the county's highest overpasses.
Caltrans engineers said they were not surprised that the 17.3-mile roadway between Norwalk and El Segundo withstood the earthquake, while portions of the Santa Monica Freeway (10) buckled and an Antelope Valley Freeway (14) overpass collapsed onto the Golden State Freeway (5).
"We've learned from every earthquake we've had in California, and we've changed the design standards each time," said Caltrans district director Jerry B. Baxter. "The Century was built using the most modern standards, and obviously, they worked."
Baxter said the key factor is that additional steel bars were used to reinforce concrete columns supporting the Century Freeway's 12 lanes and numerous overpasses, on-ramps and off-ramps.
Caltrans began requiring steel reinforcement in freeway bridges and overpasses following the 1971 Sylmar quake, which toppled freeway overpasses. The agency is in the middle of a $1.5-billion reinforcement program designed to shore up bridges and overpasses with steel encasing.
Columns supporting the bridges and overpasses along the Santa Monica Freeway--including the three that buckled and partially collapsed Monday morning--were scheduled to be retrofitted this spring, Baxter said.
"At least we knew (the Century Freeway columns) didn't need to be strengthened," Baxter said. "They are about as strong as they come, and were built with every safety feature we know of."
In fact, Baxter said, the Century is probably more seismically safe than many homes in the communities it traverses.
"People might be afraid to go back on the freeways," he said. "But most of them are living in homes that were built . . . when earthquake standards were virtually unheard of. If I were them, I'd rather be on the (Century) freeway when the next one hits."
The $2.2-billion highway opened in October, with computerized traffic monitors and closed-circuit television cameras to alert officials to accidents. The freeway was built to serve as another east-west route for commuters, but Baxter predicts it will become a primary thoroughfare as drivers seek detours around the closed sections of the Santa Monica Freeway.