(George Nikitin/Associated Press
SAN FRANCISCO - When an earthquake collapsed two 50-foot sections of the San Francisco-Oakland Bay Bridge during the 1989 World Series, the nightmares of hundreds of thousands of commuters who cross the Depression-era span each day were brought to life.
On this 20-year anniversary of the 6.9-magnitude earthquake that killed 63 people, injured about 3,800, and caused up to $10 billion in damage, the bridge reconstruction has become the largest public works project in California history and is still years from completion.
Although thousands of buildings, highway bridges, and landmarks such as San Francisco City Hall have been fortified, other earthquake safety problems are far from fully addressed in this region where specialists say another major temblor is certain.
Some schools that the state says are at risk of collapse still have not been repaired. And vulnerable apartment buildings that house hundreds of thousands of people have not been seismically retrofitted by their owners.
“The Loma Prieta earthquake is always referred to as a wake-up call, and we’re fortunate over the last 20 years that we’ve had no other major earthquakes,’’ said Jack Boatwright, a seismologist with the US Geological Survey. “Much work has been done, but we cannot rest in these efforts.’’
It took only four years during the Great Depression to build the Golden Gate and Bay bridges, but the reconstruction of the eastern span of the Bay Bridge has been plagued by costly delays and political gridlock over its unconventional design. Originally the cost was put at $1.3 billion with a 2004 completion; that has ballooned to $7.2 billion with a 2013 opening.
“What this region and the state is trying to do here is unique,’’ said Bart Ney, a spokesman for the California Department of Transportation, who is managing the project. “We’re trying to build a world-class structure, an architectural icon, and a seismic innovation all at one time in one of the most seismically challenged areas of the world. Because of the complexity of all of that, it’s taken us a long time to do it.’’
Some bridge specialists, however, say the decision to rebuild rather than strengthen the existing bridge was a pricey mistake.
A team of 40 researchers sponsored by the National Science Foundation and Caltrans to study the Oct. 17, 1989, earthquake’s effects on the bridge recommended in 1992 that the current bridge be retrofitted, not replaced, for an estimated cost of $230 million.
But a 1996 study by the Seismic Advisory Board at Caltrans disagreed with these findings, saying the cost of replacing the bridge was comparable with retrofitting it.
The new span wound up costing billions of dollars and is less quake resistant than the existing bridge, said Abolhassan Astaneh-Asl, a civil engineering professor at the University of California, Berkeley.
“You are going to get a bridge, in my opinion, that is less safe than the existing east span. The bridge didn’t need to be replaced,’’ said Astaneh-Asl, who was the lead investigator in the National Science Foundation and Caltrans five-year study of the seismic performance of the bridge’s east span, and who submitted an alternative design after officials chose to replace it.
But Ney of Caltrans said the new bridge is the safest of the designs that were aesthetically pleasing to local leaders and others who had a say in the final choice.
While cost and delays have been troubling, Ney said, there is no question the right decision was made. “The bridge is 70 years old,’’ he said. “It’s reaching the end of its life span.’’
The Bay Bridge is not the only complicated public safety project to move slowly.
In 2003, years after a newspaper investigation exposed thousands of vulnerable public school buildings in California, a state audit determined California schools could need at least $5 billion in seismic work.
But in many districts, expensive retrofitting projects are not feasible in these challenging economic times.
In 2006, a voter-approved measure set aside $200 million to help districts with seismic projects, but only five school districts have applied for the funds.