Seattle I-5 Ship Canal Bridge designed like bridge in Baltimore’s bridge collapse, UW expert says

SEATTLE — A University of Washington professor explained the design of the bridge involved in Baltimore’s bridge collapse and how the structure may have possibly played a factor in the collapse after a massive cargo ship struck it.

The Francis Scott Key Bridge in Baltimore collapsed early Tuesday after a support column was hit by a large container ship that had lost power, sending vehicles and people into the Patapsco River, authorities said.

Called the Dali, the 948-foot vessel that hit the bridge is managed by Synergy Marine Group, a Singapore-based company with over 660 ships under management around the world, according to its website. The group said the ship was operated by charter vessel company Synergy Group and chartered by Danish shipping giant Maersk at the time of the incident.

The outbound ship had left Baltimore and was headed for Colombo, the capital of Sri Lanka, Synergy Marine Group said in a press release.

Six people remain missing and are presumed dead, Rear Admiral Shannon Gilreath of the U.S. Coast Guard said at a news conference Tuesday evening. Two other people were rescued from the water.

All eight people were part of a construction crew that was filling potholes on the bridge at the time, officials said.

During its latest federal inspection, the Key Bridge scored a six out of nine, which is considered “fair,” a condition it had been labeled since 2008, CBS Baltimore reported.

The bridge passed inspection in May 2022, but there was concern with one of its columns. The reinforced concrete column was downgraded from a health index, or condition rating, of 77.8 to 65.9. It is not known whether the column of concern was the same one that was struck on Tuesday morning.

Directly, the port supports 15,300 jobs, while another 140,000 in the area are related to port activities. The jobs provide a combined $3.3 billion in personal income, according to a CBS News report. The Port of Baltimore said Tuesday that it is unclear how long ship traffic will be suspended.

BRIDGE DESIGN:

KIRO 7 News spoke with Jeffrey Berman, a civil engineering professor at the University of Washington who has nearly three decades of experience studying bridges.

“We certainly don’t see structures of this magnitude collapse very often thankfully,” he said. “It’s really scary.”

Berman said the bridge in Baltimore’s tragedy is a steel truss bridge, which was initially designed around the 1930s.

Many cities and counties across the United States have this type of bridge, however, it is no longer produced as often, he said.

“There are more cost-effective ways to do these longer span structures today. It doesn’t really have to do with safety and is really driven by costs,” he said.

Many drivers across the Puget Sound will also see this type of bridge in Seattle.

“It’s a pretty common bridge type. It’s actually similar to in Seattle to the I-5 Ship Canal Bridge. That’s a very similar type of bridge,” he said. “I think the bridge that collapsed in Baltimore, the truss is on top and I-5 ship Canal Bridge where the main structure of the bridge is underneath the roadway, but they transfer loads and are designed using very similar principals.”

In a video capturing the collapse, a large portion of the bridge fell into the water after an enormous ship strikes one area of the bridge.

KIRO 7 News asked Berman about the damage left behind.

“The back spans also collapsed. So, the spans that were not directly supported by the pier that was hit by the ship also collapsed that’s because these steel truss bridges are continuous from end to end. They’re kind of all connected. Each segment relies on the next segment for stability, for load transfer,” he said. “The span is really really really long and you need to use that kind of back spans to reduce the loads and keep the design efficient for the main span of the bridge.”

“It is possible that with a different type of bridge some of those others spans, maybe, wouldn’t have collapsed,” he added.

However, Berman stressed no bridge is designed for a large vessel to strike it.

“There’s not much that’s going to survive. I think any bridge that was struck in the pier, in particular, so the pier is the vertical element of the bridge, any bridge that is struck at its support at its pier by a vessel of this magnitude is very likely to collapse,” he said.

WASHINGTON STATE DEPARTMENT OF TRANSPORTATION:

The Washington State Department of Transportation (WSDOT) inspects more than 7,300 bridges on state, city and county roads.

“We do have some bridges that go across those cross navigable channels where barges or vessels are in the area,” said RB McKeon, a spokesperson for WSDOT.

McKeon said the agency has several tools in place in case a similar emergency were to happen in the Puget Sound to keep drivers safe.

The agency frequently communicates with the U.S Coast Guard, she said.

“If we’re working over water ways that have boat travel, we communicate with the U.S. Coast Guard and we’re under federal maritime law and they have the jurisdiction,” she said. “We’re aware of maritime horn communications. We have maritime radios on our bridges. And we do communicate with the Coast Guard and marine operators.”

Many bridges across the Puget Sound also have cameras in place to monitor for possible emergencies, McKeon said, while local law enforcement patrols the area.

“The folks that are out there sort of patrolling the water ways have our contact information for our Transportation Management Center and they would initiate their own standard operating procedures in case of an emergency,” she said.

KIRO 7 News reached out to the U.S. Coast Guard and requested an interview to learn more about its process and safety protocols.

We’re still waiting to hear back.

PORT OF TACOMA AND SEATTLE:

KIRO 7 News spotted Maersk ships in the Port of Tacoma in recent years past. The company also operates in the Port of Seattle, according to its website.

We requested an interview with the company; however, a spokesperson declined our request.

He shared the following statement:

“We are horrified by what has happened in Baltimore, and our thoughts are with all of those affected. We can confirm that the container vessel “DALI”, operated by charter vessel company Synergy Group, is time chartered by Maersk and is carrying Maersk customers’ cargo. No Maersk crew and personnel were onboard the vessel. We are closely following the investigations conducted by authorities and Synergy, and we will do our utmost to keep our customers informed.”

We also reached out to the Port of Tacoma and Port of Seattle to request an interview to understand the Ports’ involvement with Maersk.

A spokesperson shared the following statement:

“The Washington state port community was devastated to hear news of the collapse of the Francis Scott Key Bridge in Baltimore. Our thoughts are with the families impacted, the first responders, and all who are affected by this tragedy. Safety is the top priority for the Washington Public Ports Association and our member ports and partners, and we join with the worldwide maritime community in awaiting the outcome of the investigation.”

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