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Two big highway closures, Eastside lane closures, a solstice festival and a marathon will make this another good weekend to stay home, cross the city on a bicycle, or at least find a detour.

The Highway 520 floating bridge will be closed all weekend, from 11 p.m. Friday until 5 a.m. Monday.

This will allow workers to lay 10,000 tons of asphalt just east of the bridge, from Lake Washington to Interstate 405. And over the lake, concrete pouring will resume for the tall West Connection Bridge, where a new floating roadway will meld with the fixed highway in 2016, near Foster Island.

Other blockages:

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• The northbound Alaskan Way Viaduct and Battery Street Tunnel will close from 10 p.m. Friday until 5 a.m. Monday, so temporary lanes of Highway 99 in Sodo can be shifted. That will make room to build ramps for the future Highway 99 tunnel.

• In addition, one southbound lane of Highway 99 will close at South Lake Union, from 4 p.m. Saturday until 5 a.m. Monday, for utility work between Republican and Thomas streets.

• The Fremont Fair and Solstice Parade will occupy several streets just north of the Fremont Bridge, causing bus and car detours. Partygoers are urged to ride transit. Just getting there from south of downtown will be especially tough because of the viaduct closure.

• The Rock ‘n’ Roll Seattle Marathon, which starts at 7 a.m. Saturday, will close many streets, as the race passes through Seattle Center, Rainier Valley and Mercer Island.

The Interstate 90 express lanes will close from 3 a.m. to 2 p.m. Saturday, while one lane of the Interstate 5 express lanes and the Cherry/Columbia street ramp will close from 8 to 10 a.m. Also, the South Dearborn Street ramps to and from I-5 will close from 5 to 9:45 a.m.

• King County Metro Transit says more than 40 bus routes will be delayed or detoured Saturday, so riders should look up their individual routes on Metro’s service alert page:

Some motorists are fuming about the idea of having a marathon at the same time as the other closures.

State officials say the multiple Highway 99 closures were coordinated betweeen WSDOT and Seattle.

“Instead of doing two separate closures for the work, we’re doing them in one weekend,” said WSDOT spokesman Bart Treece.

Schedulers’ hands are tied, he said, because Highway 520 needs construction closures now, so that later this summer 520 will be open while I-90 undergoes expansion joint repairs on the East Channel Bridge. And then, Memorial Day, July 4 weekend, Seafair weekend and Labor Day are all off-limits.

You don’t have a lot of other choices when you’ve got these projects,” he said.

The marathon includes part of the Alaskan Way Viaduct, north of the Sodo construction zone, where cars won’t be traveling this weekend.

In updates issued Friday:

• Interstate 405 ramps and lanes are being restriped, as a phase of long-term road widening. This means up to three lanes of southbound I-405 will close from 7 0p.m Saturday until 9 a.m. Sunday, at Kirkland from Northeast 85th Street and Northeast 70th Street. And the southbound on-ramp at Northeast 85th Street will close from 3 a.m. to 7 a.m. Sunday, while the southbound exit at Northeast 70th Street will close from 3 a.m. to 8 a.m. Sunday.

• Snoqualmie Pass rock blasting resumes next week, causing one-hour closures in both directions at around 8 p.m., Monday through Thursday. Various single-lane closures or bridge repairs will be underway next week through the pass, at Price Creek, at Elk Heights, and the Vantage bridge over the Columbia River.

Mike Lindblom: 206-515-5631 or On Twitter @mikelindblom

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