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News / Clark County News

Could fatal collapse of Interstate 5 Bridge happen?

‘Anything of that size that hits a bridge will cause major damage,’ ODOT spokesman says

By Scott Hewitt, Columbian staff writer
Published: March 27, 2024, 6:04pm

Huge cargo ships do not pass underneath the Interstate 5 Bridge, so a crash and collapse on the scale of what happened Tuesday to the Francis Scott Key Bridge in Baltimore isn’t likely here.

“We never see ships of that size going up and down the Columbia River — no farther than the Port of Portland,” said Don Hamilton, spokesman for the Oregon Department of Transportation, which operates the I-5 Bridge. Upriver, Hamilton said, the water gets shallower and the ports smaller.

The Port of Portland is a few miles west (downriver) of the I-5 Bridge. When a new record was set, nearly one year ago, for the largest ship ever to dock there — a 1,200-foot-long cargo ship with 12,400 shipping containers — it didn’t have to pass under the I-5 Bridge. Neither did a pair of 951-foot-long military cargo ships that docked at the Port of Vancouver in 2020 and 2021.

River traffic that does pass below the I-5 Bridge “consists of small vessels such as tugs, barges, marine construction equipment, cruise ships and recreational vessels,” according to a document about river navigation from the Interstate Bridge Replacement Program. “Large commercial ships do not currently pass under the Interstate Bridge, as terminals for cargo ships are located downstream (west of the bridge) at the Ports of Portland and Vancouver.”

There are no plans for that to change, according to the document.

But if a massive cargo vessel ever did hit one of the unprotected support structures beneath the I-5 Bridge, Hamilton said, that might well result in disaster.

“Anything of that size that hits a bridge will cause major damage,” he said. “That was a monster ship.”

The 985-foot-long Dali was leaving the Port of Baltimore with 4,700 shipping containers, according to The New York Times, when it lost power and issued a mayday call. Within minutes, as its crew struggled to steer, the Dali drifted into a support pylon below the Francis Scott Key Bridge, which collapsed.

Some bridge supports are supplied with solid protective structures — such as rock walls, whole islands of rock or concrete “fenders” — that are designed to ward off crashes. But Baltimore’s Key Bridge had no such protections around its piers. It’s now being debated whether protective devices could have buffered against the Dali’s hard strike.

The I-5 Bridge over the Columbia River has no protective devices or fenders. Consisting of two separate spans, the bridge sits upon 10 concrete support structures set perpendicular to the roadway. They’re essentially load-bearing walls that run east-west, parallel to the river.

What’s complicated about approaching the I-5 Bridge by boat, Hamilton said, is the differing spaces between these supports and the need for river pilots to line their vessels up just right. The smallest width between bridge supports is 260 feet. The largest width is 531 feet.

“That’s where it can get tricky,” Hamilton said. “There’s a wide span for wide loads. They may have to swerve to get under the crossing.”

The St. Johns Bridge in north Portland, near the Port of Portland, doesn’t have protective devices either.

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There is one defensive factor in the I-5 Bridge’s favor, Hamilton added: It’s staffed 24/7.

“It’s a lift bridge. There are people up there responding to calls from ships,” he said. “They are watching the river for trouble, around the clock.”

Downriver in Astoria, Ore., where the largest cargo ships do come and go, the Astoria-Megler Bridge features protective wooden features called “dolphins,” which guard against floating river detritus, such as logs, but not against ships, Hamilton said.

“Probably not capable of standing up to a hard strike from a ship,” Hamilton said by email, “but maybe lessening the damage.”