Three northbound lanes of I-5 will close Friday and Saturday nights from 9 p.m. until 9 a.m. for deck repairs at the Ship Canal Bridge.

The freeway will be narrowed from Harvard Avenue East on north Capitol Hill, until drivers cross the bridge and reach the University District.

Traffic jams could begin long before the bridge, so drivers should look ahead and also pay attention to I-5 electronic messaging signs, said Angie Millar, spokeswoman for the Washington State Department of Transportation (WSDOT).

The Express Lanes will stay open northbound until 11 p.m. both nights, which will relieve some traffic congestion, WSDOT said. They’ll close afterward, until the normal 8 a.m. reopening southbound — as a precaution so materials from the repair job can’t fall down onto vehicles below, Millar said.

The Ship Canal Bridge deck occasionally crumbles, so crews must chip loose concrete to pour patches over the rebar, as in this 2018 photo by WSDOT.
The Ship Canal Bridge deck occasionally crumbles, so crews must chip loose concrete to pour patches over the rebar, as in this 2018 photo by WSDOT.

The deck patching, and repairs to expansion joints, are considered normal maintenance on the aging bridge, and take place four to six weekends a year, Millar said. The crossing was built in 1962 and carries 265,000 vehicles per day.

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The Ship Canal Bridge needs a complete deck overlay, which last occurred in 1985. But the $55 million job won’t happen until around 2026, WSDOT has predicted.

The two-deck, steel truss bridge boasts a respectable “sufficiency rating” of 68 out of 100 points, for its combined strength, traffic and navigation purposes, according to the National Bridge Inventory. Besides making a smooth surface, regular deck patches reduce the threat of seeping water and grit that might corrode steel beams.

One lane of southbound I-5 will close in Seattle on Sunday morning, from 4 a.m. to 8 a.m., between the Lake City Way onramp and Northeast 45th Street, for other repairs.

This weekend’s Seattle disruption is in addition to the overnight closures to both directions of I-5 just north of Tacoma, where record-length concrete girders will be set across the freeway for a future extension of Highway 167.

Highway 203 at south Duvall remains closed, requiring drivers to take a signed detour. WSDOT is continuing there to replace a fish culvert under the highway.

Interstate 90 through Snoqualmie Pass will be near full capacity, following asphalt paving to replace 42 broken concrete panels last week.