Pontoon Construction Hits Another Milestone

ABERDEEN, Wash. – Pontoons for a new State Route 520 floating bridge are shaping up from the inside out, and media are invited to get an up-close look at the first concrete walls.


Last week, the Washington State Department of Transportation (WSDOT) and Kiewit-General (K-G) began constructing the first interior wall sections for 33 pontoons needed to help build a new SR 520 floating bridge in Seattle. The walls are 27 feet high by 11 feet long and 8 inches thick and weigh about 29,500 pounds each.


The walls will later be raised and placed by crane inside the pontoons. The larger pontoons, which will house 90 walls apiece, will weigh as much as 11,000 tons, measure as tall as a three-story building and be as long as a football field. 


The interior walls are just the latest benchmark WSDOT and K-G have reached at the SR 520 Pontoon Construction Project. Work at the 55-acre Aberdeen project site started in February when crews began building a pontoon casting basin and concrete batch plant.