The state Department of Transportation is giving the green light to the new 520 bridge – literally.
Four “sentinels,” large pillars on each side of the bridge at the east and west ends, will be aglow at night with a green light topped by an amber beacon. The column-line sentinels will mark where the bridge transitions from land to water.
It’s just one of several new features planned for the bridge, the longest in the world.
In addition to six lanes for vehicles, the bridge also will include a 14-foot-wide path for walkers and cyclists. Because the bridge is so long, five viewing points will be built along the length and include benches where people can take a break.
Also planned are noise barriers that will extend out from the land portion of the bridge to the water portion.
These and other aspects of the bridge will be shown in an open house from 4:30-7:30 p.m. Tuesday, March 27 at Three Points Elementary School, 7800 NE 28th St., in Medina.
A similar open house will be the time time Wednesday, March 28 at the Museum of History and Industry, 2700 24th Ave. E., in Seattle.
The Washington State Department of Transportation received the 18th and final major permit needed to allow construction on March 23. The permits cover the bridge itself and the the Eastside corridor from Bellevue to Redmond.
One new aspect of the bridge will be noticed by both drivers and workers who maintain the bridge – the roadway will be elevated on the pontoons. That not only will mean drivers no longer will be hit by spray during high windstorms, but also that maintenance crews will have access to the pontoons without having to shut the bridge.
The bridge also won’t have a draw span. Instead ships will have clearance at the west end of the bridge.
Large marine equipment will be arriving at the bridge site Thursday, including a large crane on a barge. Later this summer, the first batch of 77 huge floating pontoons will be towed into Lake Washington and assembled north of the existing 1963 bridge. It will take contractors four days to tow the pontoons from Aberdeen to the lake.
The target date for completing the bridge in the end of 2014.
Including highway construction on the Eastside, an estimated 900 people have worked on the SR 520 corridor to date. More are expected as floating bridge construction ramps up on Lake Washington.
The new bridge has a lifespan of 75 years, but should, in fact, last twice as long and be able to withstand a “significant wind events,” according to John White, WSDOT SR 520 Floating Bridge Design official.
The bridge also will have crack-free pontoons, said Mike Cotten, WSDOT SR 520 Floating Bridge Director.
“We’ve learning a lot in 50 years (of building bridges),” White said.
WSDOT has $2.43 billion of $4.65 billion budgeted to build improvements in the 12.8-mile SR 520 corridor between Seattle and Redmond.
