SEATTLE -- Plans are underway to construct a pair of temporary steel bridges across the Skagit River in northern Washington state where a highway span collapsed into the water this past week.
The Associated Press has learned from an official who spoke on the condition of anonymity ahead of a formal announcement that the bridges will go up next to the original span and will allow limited travel over Interstate 5.
Planners hope to have the temporary structures in place within three weeks. Repair work would then begin on the damaged bridge, with a goal of finishing that work by fall.
The federal government is expected to cover 90 percent of the cost of the temporary bridge and the replacement.
On Thursday, a semi-truck carrying an oversize load clipped a steel truss, starting the collapse of the span and sending cars and people into the cold river waters, authorities said. The three people in the cars survived with non-life threatening injuries.
But the collapse cut access to one the most important highways in Washington state for trade, commuters and travelers.
Meanwhile on Saturday, barges arrived at the river with equipment ready to remove the mangled steel, pavement and cars in the water.
National Transportation Safety Board Chairwoman Debbie Hersman on Sunday said the bridge had withstood other over height collisions with vehicles in the past, with the most recent reported collision happening last October. She said evidence of other collisions can be seen in the spans still standing over the water.
Hersman also said a second truck with a similar cargo was traveling behind the truck involved in the collision. She said investigators are inspecting that cargo and truck to take measurements. The truck involved in the collision has also been moved off the highway on-ramp where it has been parked since Thursday.
Hersman also said investigators have traveled to Alberta, Canada to inspect the trucking company's records.
The NTSB head also said that if the truck had been on the left lane of the southbound lanes, it likely would have cleared the bridge without a collision, but added that more precise measurements need to be taken. The bridge's height clearance varies across it.
"We know the company was required to establish that they could clear the entire route," Hersman said.
The truck's cargo from Canada was headed to Alaska. Its plan was to load its cargo onto a barge in Vancouver, Wash., about 275 miles south of the border crossing.