Skagit collapse papers: Did pole strike bridge?

NTSB report offers conflicting accounts of incident

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The oversize load that struck the Skagit River Bridge was part of an oil drilling rig headed from Alberta, Canada, to Thompson Metal Fab in Vancouver's Columbia Business Center. The load was to be consolidated with the rest of a barge shipment and shipped to a customer's site in the far northern oil fields.

The oversize load that struck the Skagit River Bridge was part of an oil drilling rig headed from Alberta, Canada, to Thompson Metal Fab in Vancouver’s Columbia Business Center. The load was to be consolidated with the rest of a barge shipment and shipped to a customer’s site in the far northern oil fields.

SEATTLE — A pilot driver escorting an oversize load that triggered an Interstate 5 bridge collapse north of Seattle told investigators that the clearance pole mounted on her car never hit the structure. But in documents released by federal investigators Wednesday, one witness reported seeing the pole strike the Skagit River Bridge several times.

The National Transportation Safety Board will have to sort through the conflicting accounts as it determines what likely caused the May 23, 2013, collapse. The agency, expected to release its final report this summer, made public more than 2,000 pages of documents, including interviews, cellphone logs and incident reports.

A section of the span fell after a truck carrying a tall load hit the bridge in Mount Vernon, 60 miles north of Seattle. Two other vehicles fell into the river, and three people were rescued with minor injuries.

William Scott, who was driving the truck with the tall load, told investigators that a freight truck “came up very fast on the left” and “squeezed me as we were coming to the bridge.” He told investigators that he moved his vehicle to the right, which had a lower vertical clearance than the center lane, the NTSB said.

Scott told investigators that the pilot car driver, Tammy Detray, was in the right lane when she entered the bridge. He says “the pole went through” and that she didn’t say anything about the pole hitting the bridge. The two drivers could communicate via radio.

The vertical clearance was 18 feet above the center lanes, but it tapered to 15 feet, 5 inches at the fog lines on the right side of the roadway. The lowest portion measured over the shoulder of the roadway was 14 feet, 8 inches, according to the NTSB.

Scott said he thought his load was 15 feet, 9 inches. A Washington State Patrol report notes that the right front of the load was later measured at 15 feet, 11 inches. The top of the load collided with the far right side of the overhead truss.

The trusses have since been reconfigured, giving 18 feet of clearance for all traffic lanes.

According to the NTSB, Detray said the clearance pole mounted on the front of her vehicle was set at 16 feet, 2 inches. A state trooper measured it at 16 feet.

Detray told investigators the pole did not strike the bridge. She also said that she was using her cellphone on a hands-free device at the time of the accident, according to a report.

The driver of a Ford Ranger, Dale Odgen, who was passing both vehicles, told investigators that “saw the pole strike four or five of the bridge elements.”

Scott cleared the bridge and stopped on the right shoulder, not realizing that the bridge had collapsed until he was told by another driver who had also pulled over, according to the documents.

The 59-year-old bridge carries an average of 71,000 vehicles a day over the Skagit River on I-5, Washington’s major north-south roadway between Oregon and Canada. Workers installed an emergency span and replaced it with a permanent one in September.