Construction is under way on a double leaf concrete swing bridge across 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 progress to date is reviewed.

A double-leaf concrete swing bridge across the Duwamish River in Seattle, Washington,
represents a revival of a type of movable bridge long out of favor and incorporates new
concepts in machinery and movable bridge technology. The bridge connects two portions of
the industrial port area of Seattle across one of its major shipping channels.