Abstract
Construction is under way on a double leaf concrete swing bridgeacross the duwammish river in seattle, washington. This bridge represents a revival of a type of movable bridge long out of favor and incorporates some new concepts in machinery and movable-bridge technology. The structure and its site are described and some of the factors that led to this novel design are detailed. Construction progressto date is reviewed. This paper appears in transportation research record no. 1275, Bridge research 1990.