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July 13-14: SR 520, northbound I-405 closed

Panel replacement and rehabilitation on northbound I-405
A broken and failing concrete panel on northbound I-405 near Bellevue
A broken concrete panel on northbound I-405 near Bellevue. This is one of more than 900 that will be replaced.

SR 520 Eastside Transit and HOV project
Excavation of a large trench to install a fish-friendly culvert

Crews dug a similar trench under all lanes of SR 520 last August. This trench was 25 feet deep and 80 feet wide at road level. The trench for the culvert that will be installed on July 13-14 will be 34 feet deep and almost 100 feet wide. See more pictures for similar fish culvert installation workl

Take 5 poster image 

WSDOT thanks drivers for doing their part to help reduce and managed congestion during the combined closure of State Route 520 and northbound Interstate 405 on July 13-14.

During the closures, crews did the following:
Drivers were urged to "take 5" - take five minutes ahead of time to check WSDOT's online travel resources and plan weekend routes.

Select what you want to know more about:


Closure details

  • SR 520 closed between Montlake Boulevard and I-405 from 11 p.m. Friday, July 12 to 5 a.m. Monday, July 15.
  • Northbound I-405 lanes began closing at 8 p.m. with all lanes closed by 10 p.m. The I-90 ramps to northbound I-405 also closed. Lanes began opening at shortly after 3:30 a.m. Monday with all lanes open by 5 a.m.


What can drivers do?

WSDOT encouraged drivers to stay engaged over the weekend and plan ahead to avoid congestion by:

  • Downloading WSDOT's mobile app.
  • Following WSDOT on Twitter. WSDOT will use the hashtag #Take5 for the weekend closure.
  • Checking the Seattle traffic page for updated road conditions and incidents.

Drivers considered alternatives to their normal commute:

  • Carpooling, vanpooling riding the bus, water taxi, train or light rail.
  • Working from home or adjusting work schedules.
  • Using alternate routes where possible.
  • Delaying or combining trips.
  • Utilizing commute trip reduction

What other resources does WSDOT have available for drivers?

WSDOT offers additional tools to help drivers make informed choices before traveling:

Why did we close both at the same time?

The summer 2013 construction season is exceptionally busy.

There are a limited number of weekends available this summer to accommodate all the necessary closures for construction work. Dry weather is needed for much of this work. With a limited number of weekends available, we were faced with the possibility of highway closures on weekends such as Seafair, the Bite of Seattle, the Bellevue Arts Festival and Labor Day weekend. Combining closures allows crews to get in, get an enormous amount of work done and get out and avoid weekends with big special events.

Much of this work couldn't be done with shorter nighttime closures, either. The new concrete panels on I-405 required up to 10 hours of cure time before traffic could drive on the interstate again. The SR 520 bridge inspection each year must be completed during the summer in case inspectors discover something that needs a repair. Parts for the bridge have to be custom-made. Crews need enough lead time to either fabricate it themselves or order it and then install it before the rougher weather of fall and winter arrives.

How congested will it be?

Drivers encountered heavy congestion, mostly in the afternoons. The most heavily congested routes were northbound I-5 and westbound I-90. Surface streets in and around Bellevue will also experience additional congestion.

What work did WSDOT do on SR 520 and I-405?

For the SR 520 bridge inspection crews:

  • Repaired expansion joints on the floating bridge.
  • Inspected bridge electrical and mechanical equipment.
  • Inspected maintenance walkways and hatches.
  • Cleaned equipment and center barrier.
  • Refueled pumps and generator.
  • Performed additional preventive maintenance.

For the SR 520 widening project, crews:

  • Excavated a trench 34 to 55 feet deep and nearly 100 feet wide at the roadway level across all lanes of SR 520 west of I-405.
  • Installed 250 feet of a 300-foot-long, 11-foot-diameter fish-friendly culvert. The remaining culvert sections will be installed separately.
  • Filled in the trench, repaved and restriped the highway.
  • Learn more about the project at:

On northbound I-405 crews:

  • Sawcut and removed more than 500  hundred broken concrete panels from south of S.E. 8th Street to SR 520.
  • Poured new concrete panels.
  • Ground existing concrete.
  • Performed maintenance work.
  • More information about this project is available at: