Why experts say what happened in Baltimore won't happen to a Bay Area bridge

San Francisco Bay Area residents can rest assured: The region’s major bridges have systems in place to protect them from ship strikes, like the catastrophic one that occurred in Baltimore on Tuesday.  

The iconic Golden Gate Bridge has “the most robust protection system of any bridge on the West Coast,” according to Paolo Cosulich-Schwartz, the director of public affairs for the Golden Gate Bridge, Highway and Transportation District, the state agency that manages the bridge. 

Early Tuesday morning, the Francis Scott Key Bridge in Baltimore plunged into the water after a ship lost power and slammed into one of its supports. Cosulich-Schwartz said it would be impossible for any ship to get close to either of the Golden Gate Bridge’s two towers.

“The North Tower is half on land and half in the water, and a large vessel would run aground before colliding with the pier,” Cosulich-Schwartz wrote in an email. 

The south tower is anchored to bedrock underwater and surrounded by what’s known as a fender, a protective shield designed to prevent ships from hitting a bridge’s piers, Cosulich-Schwartz said. 

There are a variety of fender designs, some made from wood. Abolhassan Astaneh-Asl, a professor emeritus of civil and environmental engineering at UC Berkeley, said the fenders are usually attached to the pier and act in the same way that a bumper does on a car.

On the Golden Gate Bridge’s south tower, the fender is a concrete 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,” Cosulich-Schwartz said.

Astaneh-Asl said when the Golden Gate was completed in 1937, its protection system was considered the best of its kind at the time, and it’s still among the best.  

“The Golden Gate Bridge was way ahead of its time,” Astaneh-Asl told SFGATE. “If a ship comes and hits this substantial fender, then probably the fender might crack. The fender will damage the ship; the bridge is safe.” 

Caltrans manages the Bay Area’s other seven major toll bridges: the Antioch, Benicia-Martinez, Carquinez, Dumbarton, Richmond-San Rafael, San Francisco-Oakland Bay and San Mateo-Hayward bridges. All of them have protection systems in place, according to Caltrans spokesperson Bart Ney. 

Ney said the strategy to protect the bridges is mostly the same at all of them — with fenders in place — but that the particular systems are “different for each bridge,” depending on several factors, including the type of bridge and the depth of the bay at that location. 

In the past 20 years, there have been two significant “maritime allisions” — the term used to describe a moving ship hitting a bridge — in the Bay Area. Both occurred at the Bay Bridge. In 2007, a container ship called the Cosco Busan hit the bridge’s fender at the second tower west of Yerba Buena Island.

“The bridge is in fine shape,” Ney told SFGATE at the time. The tower base’s fender system, which is made of composite plastic, “performed the way it was designed,” he said.

Although the bridge was mostly unharmed, the Cosco Busan spilled 53,000 gallons of fuel oil into the bay as a result of the crash.

In 2013, a tanker ship sideswiped a Bay Bridge tower, damaging a fender but not the bridge, SFGATE reported. 

While moving ships are a big risk for bridges, earthquakes are another, particularly in California. Ney said all the major bridges in the Bay Area have undergone seismic retrofitting in the past 20 years. 

As a result, the region’s bridges are particularly sturdy, according to Khalid Mosalam, a professor of civil engineering at UC Berkeley.

“Bridges in the Bay Area tend to be a lot stronger because of their seismic retrofit or initial seismic design, which will safeguard against such a catastrophic collapse,” Mosalam, who is also the director of the Pacific Earthquake Engineering Research Center at UC Berkeley, wrote in an email to SFGATE.

The Dali cargo ship, a 985-foot-long vessel, struck one of the Francis Scott Key Bridge’s supports, causing the span to break and fall into the water within seconds. The crew had alerted authorities via a mayday call that they’d lost steering power, the Associated Press reported, so local officials were able to stop vehicle traffic just before the crash.

Six people were still missing Tuesday afternoon and presumed dead. The individuals were filling potholes on the bridge and could not be alerted in time, AP reported, citing Jeffrey Pritzker, executive vice president of Brawner Builders, which employed the workers. The Baltimore Sun reported that the bridge had been rated by the Federal Highway Administration as being in “good” or “fair” condition for the past three decades. Maryland Gov. Wes Moore told the Sun that the bridge was “fully up to code.”