The first of the four final projects to complete the SR 520 reconstruction in Seattle will resume in 2019.

Permanent floating bridges are essentially boutique structures that only make sense for certain rare kinds of sites: unusually deep bodies of water and/or bodies of water with very soft bottoms, where piers are impractical.

Transitioning rail to a floating bridge that is constantly bobbing and swaying at the whims of the water required a first-ever solution for Sound Transit.

Seattle’s Sound Transit had a challenging problem: how to get a new light-rail line on and off a nearly 1-mile-long Interstate 90 floating bridge while protecting the rails from the constant movement of the water. 

Design engineer gets technical with post-tensioning during demolition of a floating bridge in Seattle.