Could Atlanta’s bridge collapse happen in Seattle? Yes, says WSDOT

SEATTLE – State transportation officials said they are watching the Atlanta bridge collapse investigation, knowing what happened there could happen anywhere, including Seattle.

“It absolutely could,” said Travis Phelps, WSDOT spokesman, when asked if the I-85 bridge collapse could happen on I-5. “We’re very cautious, very mindful, but it can happen, bridges are exposed to risk all the time, whether it’s things underneath the bridge or just things travel around them, like train cars, tanker trucks, vehicular collisions.”

WSDOT has limitations on what kinds of vehicles can travel where and what’s stored nearby and underneath overpasses and bridges.

“We want to take any lessons we can from that,” said Phelps. “So if this happens here, were not starting from scratch reinventing the wheel we’re taking any lessons we can learn.”

WSDOT is monitoring what happened in Atlanta as new details come to light. They said they are looking for things that Seattle can avoid.

“Whatever caused this bridge to collapse burned very intensely for about an hour,” Phelps said. “It takes a lot to affect the concrete and the rebar that gives these concrete bridges their stability, so that’s something we definitely want to know.”

Washington uses similar concrete bridges, known as girders.

"Inside there’s steel rebar that gives it its stability. If you expose that to high temperatures, it can spall, crack apart, it can also melt inside. That can destabilize the bridge and cause it to collapse.”

Phelps said that was the concern in 2002, when a train car carrying alcohol caught fire near the SR 509 overpass. Phelps said the part of the concrete structure was exposed to temperatures of 2,000 degrees for 45 minutes.

WSDOT was able to stabilize the SR 509 overpass within a day, making the impact to traffic minimal -- unlike what is happening in Atlanta, or what could happen if a portion of I-5 collapsed.

“You cannot have a regular commute the next day, or probably for the next month,” said Phelps. “So everyone in Atlanta is doing their part to change the way they drive until this can get fixed.”

In Atlanta, the flames ignited in a fenced-in area under the I-85 bridge where the state stores construction materials and supplies near the overpass, state Department of Transportation Commissioner Russell McMurry said.

McMurry initially said the materials stored under the highway were PVC pipes, but later said they were HDPE -- high-density polyethylene -- pipes. He said the conduits are used in the "traffic management, cabling, fiber-optic and wire network."

The material had been stored there "for some time, probably since 2006 or -7," McMurry said.