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I-5 to Medina: Bridge Replacement and HOV Project


Medina to SR 202: Eastside Transit and HOV Project

Pontoon Construction Project groundbreaking
Pontoon Construction Project Groundbreaking

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April 9, 2015


All SR 520 pontoons now on Lake Washington!

The final three pontoons needed for the new SR 520 floating bridge arrived Thursday, April 9 on Lake Washington, their new home for the next 75-plus years. The final three pontoons, which were built in Aberdeen, arrived after a three-day journey from Grays Harbor and a trip through the ship canal in Seattle. You can check out photos on Flickr, or enter our pontoon-photo contest (pdf 317 kb) by submitting your top shots on Twitter (@wsdot_520) via #520Pontoon, for the chance to win a tour of the new floating bridge!

This milestone brings the total number of pontoons on the lake up to the full 77 needed for the new floating bridge. 

Crews on Lake Washington have made tremendous progress building the new floating bridge. To date, more than 60 percent of the pontoons are bolted into their final locations, and installation of bridge elements such as high-rise bridge deck and low-rise roadway deck sections continues. The new bridge, featuring six lanes and a bicycle/pedestrian path, is designed to resist stronger windstorms than the existing bridge. The new bridge is scheduled to open in spring 2016.

In the meantime, work continues on the West Approach Bridge North, which will link the new floating bridge to the Montlake interchange. This project also will extend the regional bicycle/pedestrian path to Seattle. The new approach bridge is expected to be complete in summer 2017. WSDOT continues to work with the Legislature to identify funding for the remaining project elements in Seattle to complete the corridor all the way to I-5. 


Pontoon F enters the Montlake Cut early Thursday evening, April 9 en route to Lake Washington.