Congestion is expected on Interstates 5, 90 and 405 this weekend, Oct. 15-17, as construction crews close much of State Route 520, including the floating bridge.

All SR 520 ramps and highway lanes close at 8 p.m. Saturday, Oct. 15, from Montlake Boulevard in Seattle to I-405 in Bellevue. Lanes will reopen by 5 a.m. Monday, Oct. 17. SR 520 will remain open between I-5 and Montlake Boulevard, and from I-405 east to Redmond.

Work this weekend includes installing 24 huge concrete girders for a new overpass at Evergreen Point Road in Medina and creating a median work zone for future improvements east of 84th Avenue Northeast.

The closure could affect traffic to two sporting events in Seattle this weekend:

• The University of Washington football game begins at 12:30 p.m. Saturday, giving fans plenty of time to leave Husky Stadium after the game before SR 520 closes at 8 p.m. for construction.

• Soccer fans can cross SR 520 to get to the 7:30 p.m. Saturday Sounders FC game but will need to use an alternate route across or around the lake after the game.

Here are the details:

• SR 520 mainline and floating bridge: All lanes and ramps in both directions between Montlake Boulevard in Seattle and I-405 in Bellevue close from 8 p.m. Saturday, Oct. 15, to 5 a.m. Monday, Oct. 17.

• SR 520 ramps: All SR 520 ramps in the construction zone closed through the weekend, except the 108th Avenue Northeast ramp to eastbound SR 520 remains open.

• Still open: SR 520 remains open to traffic from I-5 to Montlake Boulevard, and from I-405 east to Redmond.

• Closure information and detour maps are online.

• The I-90 express lanes open westbound 9:30 a.m. to 7:30 p.m. and switch to eastbound by 8:30 p.m. Saturday, Oct. 15

• The I-90 express lanes open westbound 9 a.m. to 12:30 p.m. and switch to eastbound by 1:30 p.m., Sunday, Oct. 16.