BRIDGE CONSTRUCTION: WSDOT names contractor for S.R. 520 west approach bridge

July 25, 2014

West Approach Bridge North will be supported by solid columns fastened directly to the bottom of Lake Washington

With the contract for the West Approach Bridge North Project awarded, crews are one step closer to breaking ground in Seattle on the S.R. 520 Bridge Replacement and HOV Program. The 6,100-ft-long structure will carry traffic across the westbound lanes of S.R. 520 from the new floating bridge to Montlake.

The Washington State Department of Transportation (WSDOT) received five contactor proposals for the project. Of those, Flatiron West Inc. submitted the lowest bid of $199.5 million, which is below the WSDOT engineer’s estimate. Construction will begin this fall, with the new West Approach Bridge North scheduled to open to drivers in 2017.

“The new S.R. 520 floating bridge will be the world’s longest floating bridge, but it actually ends more than a mile from shore,” said WSDOT S.R. 520 Program Administrator Julie Meredith. “The new approach bridge will serve as a vital connection between the new floating bridge and the commerce centers of Seattle.”

Unlike the new floating bridge, the West Approach Bridge North will be supported by solid columns fastened directly to the bottom of Lake Washington. The new approach bridge replaces a 51-year-old, hollow-column structure no longer suited to today’s traffic conditions and vulnerable to earthquakes. Just like the new floating bridge, the new westbound approach bridge will feature wider shoulders, a dedicated HOV lane and a path for walkers and cyclists.

The contract award announced today is one of many milestones for the S.R. 520 Bridge Replacement and HOV Program:

  • Sixty of the new bridge’s 77 pontoons are now constructed, with the remainder scheduled for completion by early 2015;
  • The Eastside Transit and HOV Project is bringing new highway lanes, transit stops and a regional bike-and-pedestrian path to the east side. WSDOT continues to open these facilities as they are completed this summer, and the full project is scheduled for completion later this year; and
  • This fall will see completion of the new West Connection Bridge, and the new S.R. 520 floating bridge is expected to open to drivers in spring 2016.

WSDOT is working with the city of Seattle and other stakeholders on designs for further S.R. 520 improvements that are currently unfunded. These include construction of a six-lane segment of S.R. 520 from Montlake to I-5, a new Portage Bay Bridge, two highway-overpass lids in Seattle, and a new west approach bridge for eastbound traffic. The plans will be presented to the 2015 state legislature.

Sponsored Recommendations

The Science Behind Sustainable Concrete Sealing Solutions

Extend the lifespan and durability of any concrete. PoreShield is a USDA BioPreferred product and is approved for residential, commercial, and industrial use. It works great above...

Proven Concrete Protection That’s Safe & Sustainable

Real-life DOT field tests and university researchers have found that PoreShieldTM lasts for 10+ years and extends the life of concrete.

Revolutionizing Concrete Protection - A Sustainable Solution for Lasting Durability

The concrete at the Indiana State Fairgrounds & Event Center is subject to several potential sources of damage including livestock biowaste, food/beverage waste, and freeze/thaw...

The Future of Concrete Preservation

PoreShield is a cost-effective, nontoxic alternative to traditional concrete sealers. It works differently, absorbing deep into the concrete pores to block damage from salt ions...