Just as Washington state is opening up from the COVID-19 pandemic, travel through Seattle becomes harder this weekend when the southbound mainline of Interstate 5 will close for repaving in Sodo.

It’s the first of 16 weekends when most southbound lanes will be blocked during 2021 and 2022.

This weekend, only a single lane, on the collector-distributor road to the right, will continue through downtown toward Boeing Field.

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Lane reductions are planned from Friday at 7 p.m. until Monday at 5 a.m. There will be no southbound express lanes access this weekend, and ramps from Interstate 90 into southbound I-5 will also close. Drivers can expect delays and diversions a couple of miles sooner, as they approach downtown.

If people drive as usual, southbound I-5 might be stop-and-go for 6, 8, even 10 miles, said Tom Pearce, spokesperson for the Washington State Department of Transportation (WSDOT).

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As of Monday, highway traffic had rebounded to 98% of pre-COVID levels statewide, and 93% on I-5 through Sodo, state data shows.

“People need to do something else,” Pearce said. “They need to go around. They need to ride transit. They need to postpone their trips until off hours.”

Express lanes will stay pointing north, giving drivers that direction a break on Saturday and Sunday late mornings when congestion normally appears.

WSDOT will accommodate Sounders FC fans Saturday night, by temporarily opening the Sodo entrance ramp from eastbound I-90 (near Edgar Martinez Drive) onto southbound I-5, after the 6 p.m. match against Vancouver.

Contractors this weekend will spread a thin layer of polymer concrete over pavement that’s worn out after 55 years to the left side of the southbound freeway.

Then on the July 9-12 weekend, the job flips, so crews repave the right side of the 1 1/4-mile corridor. Only the far left lane will be open through downtown and Sodo.

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Fortunately, Sound Transit this month has restored normal light-rail frequency, to a train every 10 minutes between the University of Washington, downtown and SeaTac.

On the other hand, light rail service will be severed Sunday morning from 5 a.m. to 11 a.m. north of Sodo Station, while WSDOT conducts routine inspections of bridges over the light rail tracks. This work requires turning off overhead power lines to the trains. . Shuttle buses will carry train customers to downtown and Capitol Hill stations.

“In previous years this work has finished earlier, and we’re hoping that will be the case,” Sound Transit CEO Peter Rogoff said Thursday.

From WSDOT’s view, it’s hard to find summer weekends to make daylight inspections, without overlapping with other roadwork, and Sunday morning usually doesn’t draw many rail riders, said spokesperson Bart Treece.

After WSDOT’s new pavement layer is finished, additional freeway lane closures are expected the July 16-19 and Aug. 6-9 weekends, Pearce said, as the focus shifts to expansion joints between elevated road decks.

Over the next two years, 40 steel-covered joints will be replaced. Each requires 55 hours of work, as workers chip away old steel edges and insert waterproof silicone joint fillings.

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WSDOT performed the same improvements in August 2007 in the northbound Sodo lanes of I-5. The road surface cures in only three to four hours, and it’s more watertight than conventional concrete. After 14 years, the polymer concrete remains in excellent shape.

The southbound lanes needed work a decade ago. But money was tight, as the agency and Legislature devoted new gas-tax dollars to launch the Highway 520 rebuild and the Highway 99 tunnel.

This year’s work is covered by an 11.9-cent gas tax increase the Legislature passed in 2015. C.A. Carey of Issaquah is prime contractor for the $27.5 million job.

“Most people don’t think about it, but this section of I-5 is a bridge supported by columns and has expansion joints to help the bridge adjust to changes in weather and the weight of vehicles,” said WSDOT Project Engineer James Harper in an announcement. “We’ve had to do several emergency repairs on joints in this area in the middle of workdays during the past few months. Replacing these joints during planned closures will reduce the need for emergency repairs.”

Broken steel joint covers sprung into I-5’s Sodo traffic lanes in 2014 and 2015, requiring emergency repairs and blocking traffic for miles. WSDOT has repaved segments of I-5 since then but others remain bumpy, including the Ship Canal Bridge.