The new permanent below-deck girder bridge span to replace the 160-ft-long section that toppled into the Skagit River in May won’t have any vertical height clearance concerns. And soon the remainder of the 1,112-ft new Skagit River Bridge will have a more worry-free uniform vertical clearance to help reduce potential collisions.
Washington State Dept. of Transportation officials announced this week a plan to eliminate the curves in the bridge’s current support structure that offers 18 ft of vertical clearance at the center of the bridge, but only 15 ft 6 in. of clearance as the supports curve downward at the fog line, making the bridge the state’s lowest steel structure over Interstate 5.
A $4.5 million project funded by the Federal Emergency Fund and Washington State Dept. of Transportation’s bridge preservation program will remove the curvature of the 18 horizontal supports, giving the bridge a uniform 18-ft vertical clearance along the entire width of the four lanes and shoulders.
“We expect the volume of oversize loads to continue to grow into the future,” says Jay Drye, WSDOT acting assistant regional administrator. “By raising the vertical clearance above the right lane, we hope to reduce the chances of a similar bridge strike in the future.”
Contractor crews will remove the outside portion of each sway member and portal that currently arcs down, Drye says. They will then replace the removed sections with straight horizontal supports. Bridge supports will also be retrofitted with reinforced steel components to add strength in case the bridge is struck again.
During the work, crews will also perform maintenance activities such as replacing rivets below the deck and painting.
WSDOT plans to close the bidding process on Aug. 7, with work commencing in September.
An oversize semi truck traveling southbound in the right lane on May 23 struck the bridge. Guy F. Atkinson Construction opened a temporary replacement span on June 19 and workers with Max J. Kuney Co. are now building a $6.87 million permanent replacement in the water adjacent to the temporary bridge. They expect to slide the new bridge into place shortly after Labor Day.
Work on the vertical clearance project will occur during the night, finishing no later than Nov. 23.
WSDOT made no mention of the project until this week, after learning federal funding was available to ensure that the Skagit River bridge will no longer be the lowest on I-5.