U.S.

Building A Better Bay Bridge

By CBSNews.com staff CBSNews.com staff

September 13, 1998 / 8:28 PM EDT / CBS

The Bay Bridge carries 280,000 vehicles a day between Oakland and San Francisco, reports CBS News Correspondent Bob Orr. However, its towers of steel have proved no match for the whims of nature.

On opening day in 1936, the world marveled. The Bay Bridge was the longest structure of its kind and the deepest anywhere. It consumed more than 6 percent of the nation's steel and its builders thought it would last forever.

But in 1989, an earthquake 60 miles away sheared off a huge section of the upper deck.

"You have adjoining towers where one sits on rock and one is on soft sediment. They vibrate differently," says engineer Denis Mulligan. "One vibrates very slowly, the other quickly. And there's a bridge between those two towers, and that's very challenging from an engineering standpoint."

Engineers decided the only way to make the bridge safer for future earthquakes was to build a new one, replacing the weak span between Yerba Buena island and the East Bay -- where the bridge supports rest on mud, and where the bridge snapped.

The new bridge will have a single steel tower divided into four tapered columns. But the planned billion-dollar bridge only seems to make engineers happy.

The loudest criticism is being leveled by newly elected Oakland mayor Jerry Brown who calls the new bridge a "roadway on stilts."

"We need a bridge of a tremendous design," he says. "It ought to be as memorable as the Golden Gate Bridge."

Brown has zeroed in on the main reason that the new bridge raises such passion: The Bay Bridge has always seemed like the ugly sister to its neighbor at the Golden Gate. Drivers heading east from San Francisco travel through what is at best a big metal cage. The new design promises a different experience.

"...Instead of being under the bridge that was going west, you are now side by side and afforded quite beautiful views to the entire East Bay," says bridge architect John Kriken.

Many residents are not convinced that the "perfect" design isn't out there waiting to be imagined. But the bridge engineers are realists -- they know the current Bay Bridge is not likely to withstand another severe quake. They know that the clock is ticking.