The Washington State Department of Transportation (WSDOT) reached a milestone this week on the State Route 520 floating-bridge project, as crews added the first three of many bridge-girder placements to the west of the floating bridge.
This new structure is located north of SR 520 nearby Lake Washington. The crews transported and installed these three large girders on the columns that are established between Montlake Boulevard and the new floating bridge.
The girder delivery has just begun. WSDOT crews will continue to transport and install 350 additional girders. These girders are installed vertically, each one as tall as a 16-story building. If the girders were all placed end to end, they would stretch over 10 miles.
The new road deck with the new girders will lengthen the westbound lanes of SR 520 from Montlake in Seattle to the new floating bridge.
The girders, some measuring 150 feet long and 8 feet tall, will make up a significant portion of the structure for the West Approach Bridge North. The project is expected to be finished by summer 2017.
The girders are built in Tacoma, then are transported using East Lake Washington Boulevard and Interstate 5.
WSDOT has released a schedule of traffic details concerning the closure of SR 520. The most recent closure started on Wednesday at 11 p.m. and will end Friday at 5 a.m. During this time, the state route is closed from Montlake Boulevard to 92nd Avenue Northeast.