Construction crews will block all lanes of the eastbound Highway 520 bridge from 11 p.m. Friday until 5 a.m. Monday, while they begin to build a landscaped lid at the Montlake interchange.

This is the first of four weekend closures to set a total 114 girders, similar to other lids east of Lake Washington. Drivers may go eastbound from I-5 but must exit at Montlake Boulevard. The floating bridge walk-bike trail will remain open, with detours near the work zone.

A similar closure is planned Feb. 5-8 in the westbound direction, then westbound Feb. 26-28 and eastbound March 5-7.

Later in 2021, north-south Montlake Boulevard traffic will temporarily be detoured onto the unfinished lid, while crews demolish and replace the old Montlake overpass.

When completed, the three-acre lid will hold greenery, walk-bike trails, and bus lanes for a transit station. The lid, new interchange and bridge spans over the Lake Washington shore will open in mid-2023. Those are a $455 million phase of the overall $4.6 billion Highway 520 project.

Also this weekend, the state will close all but one lane of northbound I-5 from the I-90 junction to University Street, from 11 p.m. Friday until 5 a.m. Saturday. Crews will inspect the fire-safety systems below the state convention center. Express lanes will stay open, as will the separate entry-exit lanes to the right of the mainline.


In a late change, the Washington State Department of Transportation (WSDOT) spokesman Joe Calabro says its crews found pavement peeling away from I-5 near Lake Union, and must perform urgent night repairs. Two lanes of southbound I-5 and the I-5 onramp from westbound Highway 520 will close from 10 p.m. Saturday until 6 a.m. Sunday.

Sound Transit’s announced closure of Highway 99 (International Boulevard South) in Des Moines on Friday night is cancelled, because contractors can move equipment without blocking traffic, a Friday afternoon update said.

A planned late-January rebuild of the southbound First Avenue South bridge deck bearings will be postponed until March, because the contractor has yet to obtain materials. The job requires all-day lane reductions to two lanes, and full overnight closures.