The construction season doesn’t end with summer for Seattle-area megaprojects, which will cause traffic closures on Highways 520 and 99 this weekend.
The Highway 520 floating bridge will close from 11 p.m. Friday until 5 a.m. Monday, so that crews can demolish unused ramps that fly over the main highway. One lane westbound will close Friday at 9 p.m., and the entire bridge closes at 11 p.m., said spokesman Ian Sterling.
The “ramps to nowhere” were built for the R.H. Thomson Expressway, a crosstown freeway the City Council canceled in 1971 following citizen protests. It will take several months to remove all the ghost ramps, including the 37-foot-high span where summer revelers jump into a silty-bottomed lagoon.
A total 66 of the 77 pontoons for the new floating bridge have reached Lake Washington. All but three of the 23 full-size pontoons have been finished at Grays Harbor and towed to Seattle. Another 54 smaller pontoons are being attached to the sides of the bridge, to add stability.
Meanwhile, Highway 99 closures come in three phases:
- The Battery Street Tunnel and South Lake Union segments will be closed from 10 p.m. Friday until 5 a.m. Monday as far north as Valley Street. Crews will perform utility work, and paving where Harrison Street meets Aurora Avenue North.
- The entire Alaskan Way Viaduct, and lanes as far south as Spokane Street, close from 6 a.m to 6 p.m. Saturday and Sunday for a semi-annual inspection of the 61-year-old roadway.
- The stretch from Mercer Street to the Aurora Bridge also closes from 8 a.m. to noon Saturday, up to North 39th Street, for the 2014 Making Strides Against Breast Cancer walk.
The closures were planned this weekend because the Seahawks will be away playing in St. Louis, instead of attracting traffic into the city.