MOUNT VERNON — Now that the I-5 bridge over the Skagit River has a new section in place, crews are working to make sure the span doesn’t suffer another freak collapse.
Starting on Monday night, officials will regularly close the bridge during nighttime hours while they retrofit and reinforce the span’s overhead structure. The primary goal is to raise the clearance height of the bridge to be 18 feet all the way across the span.
A portion of the bridge collapsed in May when an oversize truck load clipped a portion of the overhead structure, sending one 160-foot section and two vehicles with three people into the water. No one was killed.
After the bridge collapse, officials installed a temporary span in June to allow traffic to flow through the area. On Sunday, workers slid a permanent new section into place.
Inspection records show evidence that the bridge has been clipped by big rigs dating back to the 1970s. Because of the design, the current vertical clearance on the bridge is 18 feet above the center lanes, but it tapers down to 15 feet, 6 inches at the fog lines on the right side of the roadway.
Crews plan to complete the retrofit by mid-November. The cost of the project is more than $4 million and is primarily funded by federal emergency relief money.
The bridge carries roughly 70,000 vehicles a day. During closures, traffic will be rerouted off the interstate and over a bridge to the east of the I-5 span. Oversize and overweight loads will be detoured even when the bridge is open.