Baltimore bridge collapse is ‘a reminder of what’s at stake’ in Vancouver

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British Columbia officials have been aware of the risk of a ship colliding with the Lions Gate and Ironworkers Memorial bridges for almost a decade, but plans to install improved collision barriers on both bridges are still in the early stages.

The focus on Metro Vancouver’s bridges comes after a freighter lost power and crashed into the Francis Scott Key Bridge in Baltimore on Tuesday morning. Six construction workers who were fixing potholes in the bridge deck when it collapsed are presumed dead.

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In 2016, a group of retired engineers identified the risk of a ship collision on the Ironworkers Memorial Bridge and urged the federal government to make a decision. complete risk analysis before approving the Trans Mountain pipeline expansion. A short video released with the group’s report showed an oil tanker with a rudder failure hitting the CN Rail bridge before collapsing the Ironworkers bridge.

Eugene Kung, an attorney with West Coast Environmental Law who helped the group with publicity, said he was “horrified” to see the Maryland bridge collapse this week.

“It was exactly the kind of scenario that was envisioned,” said Kung, who regularly crosses the Ironworkers Bridge by car and bicycle. “It’s taken for granted, but this is a reminder of what’s at stake.”

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Peter McCarthy, an activist with the Wilderness Committee, said the provincial government studied the issue independently of the pipeline’s approval in 2018 and confirmed the bridges did not meet certain standards.

“The good news is that the province is planning to address the problem,” he said. “The bad news is that they are still in the design phase.”

Tanker traffic under the Ironworkers Bridge is expected to double when Trans Mountain begins pumping oil in the coming months.

A ship strike would be a “nightmare scenario,” McCarthy said. “It’s frustrating that people have been raising this concern for a decade and we’re still in the same place.”

In it 2018 report Prepared for the Ministry of Transport, engineers found that the south tower of the Lions Gate Bridge faced the greatest risk from the “flared bow” of a container ship or cruise ship. The top of the bow could hit the tower in a weak structural location above the water and cause serious damage.

Last spring, the provincial government issued a request for proposals for a firm to design vessel impact protection works for both North Shore bridges.

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According to a Press release, at the Lions Gate Bridge, the existing concrete collar at the base of the south tower would be enhanced with a water-submerged rock fill berm, similar to that already existing on the north tower. The sloping berm would cause ships to run aground before hitting the bridge tower. At the Ironworkers Memorial Bridge, in-water diversion structures would be installed.

The Transport Ministry did not respond to questions about the status of protection works before the deadline.

But Tony Yang, a civil engineering professor at the University of British Columbia, said “there is no bridge in the world that can lose its foundation and still stand.”

“If you tear down a pier, the same thing will undoubtedly happen to all the bridges,” he said. “The real question is what is the risk of that happening?”

Yang said there are ways to mitigate the risk through operational strategies, including strict regulations to keep ships away from bridge towers, limiting ships’ speed or requiring tugboats to guide them into port.

He said engineers can also design bridges for larger impacts or install countermeasures, such as bumpers, to dissipate or divert energy.

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Yang said engineers around the world are watching the Baltimore disaster.

“We were devastated,” he said.

In a statement, Shri Madiwal, acting vice-president of operations at Vancouver’s Fraser Port Authority, said the port has created traffic control zones that limit ship speeds, as well as transit windows based on height and currents. of the tides, the size of the boat and the air draft. .

In 2017, the port authority changed the navigation channel under the Lions Gate Bridge from a two-way channel to a one-way channel to allow ships to stay in the center of the channel, he said.

Additionally, tugboat support is required, and each foreign vessel over 350 gross registered tons must use a local marine pilot when entering British Columbia waters.

“We have supported the British Columbia Ministry of Transportation and Infrastructure’s planning to strengthen the resilience of bridges in Burrard Inlet,” he added.

The City of Vancouver is responsible for maintaining the three bridges that cross False Creek. In a statement, the city said a previous risk assessment concluded that the impact of smaller vessels allowed into False Creek “could not cause significant structural damage.”

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In a situation where an unauthorized vessel approaches False Creek, such as a loose barge, the city would follow its emergency response procedures and consider an immediate closure of the bridge.

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