After more than 50 years of maintenance of a 22-mile stretch of Interstate 5 south of Seattle, Washington State Dept. of Transportation officials say the time has come for a full rehabilitation.

Between Kent and Seattle, one of the state’s largest projects ever of this kind will take three years to replace worn expansion joints, broken concrete panels and rutted roadway.

“We’ve been maintaining I-5 for more than 50 years, but it’s time for major preservation work so the interstate can continue to serve our region for decades to come,” Lorena Eng, WSDOT northwest regional administrator, says in a statement.

Work started this month on the first of two phases, as Gary Merlino Construction Co. will restore northbound I-5 between South 260th Street in Kent and the Duwamish River in Tukwila as part of a $31 million contract. To complete the 8.9-mile rehabilitation by fall 2018, crews will replace eight expansion joints on two different bridges, repave four miles of all lanes, replace about 440 broken concrete panels and grind concrete sections to eliminate ruts.

Later this year, phase 2—a contractor for this portion has not yet been named—will include work on I-5 between Martin Luther King Jr. Way and Northeast Ravenna Boulevard in Seattle. That work, scheduled to wrap in late 2019 with a budget of $36.2 million, covers a 13-mile section of elevated freeway. It will include replacing 37 expansion joints, replacing all concrete panels from near the West Seattle Bridge to near the express lanes ramp except for on bridges, replacing hundreds of broken concrete panels, grinding concrete to remove ruts, replacing four bridge approach slabs on three separate bridges and repaving 24 on- or off-ramps.

Phase one will include reducing northbound I-5 to two lanes on 10 weekends. The second phase will take place at night, but in 2018 and 2019 could require up to 16 weekends of northbound I-5 lane closures. 

Follow Tim Newcomb on Twitter at @tdnewcomb