How strong are Bay Area bridges? Here's what ABC7 I-Team uncovered

Thursday, March 28, 2024
How strong are Bay Area bridges? Here's what ABC7 I-Team uncovered
In the wake of Baltimore's Francis Scott Key Bridge collapse, the ABC7 News I-Team took a look at the durability of Bay Area bridges.

SAN FRANCISCO (KGO) -- The I-Team went through thousands of records looking into inspections, condition ratings and structural evaluations of Bay Area bridges. Here's what we found.

Overall, around 36% of Bay Area bridges are listed as in good condition. That's less than the percentage statewide - about 46.1% of California's 25,818 bridges are in the good condition category, according to 2023 national bridge inventory data from the Federal Highway Administration (FHWA).

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Golden Gate Bridge

According to the Golden Gate Highway Transportation District, the Golden Gate Bridge has the most robust ship collision protection of any bridge on the West Coast.

"The North Tower sits half on land and half in the water, and a large vessel would run aground before colliding with the pier," the district told ABC7 News in a statement. "The South Tower, which is anchored to bedrock beneath the water, is protected by a concrete fender ring extending 40 feet deep, the same depth drawn by a large ship. The concrete fender is filled with sand, similar to a highway crash barrel, and is 27 feet thick at its base, providing significant protection against collisions."

However, the Golden Gate Bridge is considered to be in fair condition, according to the FHWA data.

Paolo Cosulich-Schwartz, Director of Public Affairs for the Golden Gate Bridge Highway Transportation District, said the designated inspection timeframe for the bridge is every 24 months.

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"The Golden Gate Bridge was built with rivets, not welds, and we perform inspections every two years," he said.

The data, which was released last June, shows the last inspection recorded was in December 2020 -- meaning it appears the bridge is not meeting the federal inspection standard of 24 months. But Cosulich-Schwartz said the most recent report is not in the released FHWA dataset and the latest Golden Gate Bridge inspection was completed in December 2022. As of that date, the bridge had no structural deficiencies.

"The FHWA gave the Bridge's structural elements -- the roadway, superstructure, and substructure -- all either a 'good' or 'fair' rating," Cosulich-Schwartz added.

The December 2022 inspection included the entire underside of the suspension spans, all 255 bridge floor beams, the entire underside of the steel deck totaling 400,000 square feet, nearly 13,000 feet of stiffening trusses and over 4,000 deck support pedestals.

The bridge is currently undergoing the final phase of a seismic retrofit that will be completed in 2029.

Bay Bridge

The last recorded inspection for the west span of the Bay Bridge was in December 2022. The east span of the bridge was last inspected in September 2021, according to the national bridge inventory data.

The San Francisco side, built in 1936, is listed as in fair condition. The eastern span, built in 2013, is listed as in good condition.

Both spans of the bridge are required to be inspected every two years.

In 2007 there was a close call involving the Bay Bridge and the container ship Cosco Busan, but a Metropolitan Transportation Commission spokesperson said the fenders made a huge difference in protecting the bridge.

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"The fenders did their job in that case," John Goodwin, MTC Assistant Director of Communications, said. "So there was no damage to the bridge itself. That said, there was heavy damage to the fenders, not to mention to Cosco Busan and to the Bay."

MTC and Caltrans are applying for a $167 million federal grant from the U.S. Department of Transportation to upgrade the fender system - also known as the Ship Collision Protection System - on Bay Area bridges.

Which bridges are in the worst condition?

We found 332 Bay Area bridges - about 8.2 percent - are in poor condition. That area spans about 839,909 square meters.

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Alameda County has the highest number of bridges in poor condition, with a total of 67 in that category. Santa Clara County is not far behind with 60 and Contra Costa County is third, with 55 bridges in poor condition.

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At least a dozen bridges in the Bay Area are supposed to be inspected once a year at a minimum.

"Annual inspections are required for some welded steel bridges, since they can be prone to fracture," Cosulich-Schwartz said.

The majority of bridges in the nine counties are required to be inspected every two years, but over 600 only have to be inspected once every four years.

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