520 bridge pontoons taking shape on Lake Washington
Local crews are working on Cycle 5 of pontoon construction for the State Route 520 floating bridge, and as 2/3 of the work has been completed for the structure, the bridge is taking shape on Lake Washington.
Late last week, construction crews completed the first joining of two immense, concrete pontoons that will support SR 520 as it crosses the water.
Crews on Lake Washington used 80 bolts, each 16 to 20 feet long and close to 800 pounds, to secure Pontoon V to Pontoon W, both built in Aberdeen.
“With this joining, the new bridge is beginning to take shape,” says Julie Meredith, director of the SR 520 Program . “This is the first of 21 longitudinal pontoons that will be joined to form the backbone of the new floating bridge.”
Pontoon V is one of the bridge’s longitudinal pontoons. Pontoon W is one of the bridge’s two cross pontoons, which bookend the longitudinal structures on either end of the lake.
Fifty-two of the new bridge’s 77 pontoons have been built so far. In coming months, crews will align, anchor and bolt together additional pontoons, said Meredith.
Local pontoon construction is estimated to finish up in Aberdeen in the spring of 2015.
The final cycle is only 3 pontoons and should be finished faster than previous cycles.