Permanent I-5 bridge replacement on target for early September

By David Tanner, Land Line associate editor | Thursday, August 15, 2013

The Washington state Department of Transportation says it’s on track to bring a permanent replacement of the Skagit River Bridge on Interstate 5 online just after Labor Day. The agency spent this week moving large steel girders into place alongside a temporary span that was erected after a 160-foot section of the bridge collapsed in late May.

“We’re still on schedule to replace the temporary span in early September, shortly after Labor Day weekend,” WSDOT spokesperson Jay Drye said in a statement.

Crews spent the summer driving piles into the river to create work platforms next to the temporary span. Once the girders are in position, contractors will slide them into their permanent home using a manufactured rail system.

Drye said the agency must close I-5 to complete the job, but hopefully not for long and with minimal disruption. Total cost for the permanent span is estimated at $6.9 million.

During the early evening hours of May 23, a truck hauling a permitted over-dimensional load was crossing the bridge behind a pilot car when it struck supports above the bridge deck. Seconds after the strike, a 160-foot section of the bridge collapsed behind it. No one died, but three people had to be rescued from the river after their vehicles fell in.

Federal and state investigators have released only preliminary reports so far and the investigation continues.

The National Transportation Safety Board released a statement this summer saying the driver of the oversized load reported that he was forced to stay to the right by a truck that was passing or attempting to pass him as the vehicles arrived at the bridge. The overhead clearance was lower at the right shoulder than it was down the centerline.

The investigation revealed that the bridge was classified as fracture critical, a design term that rates a structure’s ability to withstand an incident such as a natural disaster or strike by a heavy vehicle.

Prior to the collapse, the bridge carried 71,000 vehicles per day.

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