Construction
27 Jun 14
Installation begins of hinged span for SR 520 floating bridge
Installation begins today of a 58m-long hinged transition span on what will be the world’s longest floating bridge.
Contractor crews working for Washington State Department of Transportation in the USA are using a large derrick crane to install the span and the operation is due to be completed tomorrow.
Five 58m-long girders make up the span, each of them weighing 45t. Once assembled, the transition span will serve as the threshold between the moveable, floating bridge and the highway’s stationary, elevated segment near Lake Washington’s eastern shore.
“The span is a unique piece of hardware integral to the new floating bridge,” says WSDOT deputy construction manager Greg Meadows. “In the same way a hinge allows a door to move while the frame stays rigid, this span moves up, down and side-to-side along with the floating bridge, while the highway remains stationary.”
Washington state has four of the five longest floating bridges in the world, Meadows noted, and the new bridge’s hinged transition span is bigger than any previously installed there.
The span will support the new bridge’s roadway for eastbound lanes at the east end of the new floating bridge. A wider hinged span for the westbound lanes and a cross-lake bicycle/pedestrian path will be installed later. Similar spans will also be installed at the west end of the floating bridge in 2015.
