The article describes a concrete, segmental, box-girder, swing bridge with twin leaves weighing 7,500 tons (awarded the 1992 Outstanding Civil Engineering Achievement Award), the only one of its kind in the world. The $33.5 million, West Seattle Low-Level Swing bridge has leaves with 173.5 ft tail span and a 240 ft channel span, clearing the channel by 55 ft. It is the only hydraulically operated double-leaf concrete swing bridge in the world. It is a wing structure with 2 pivot piers on the river banks rather than the usual single pivot mid-channel. The span between the center line of the pivot piers is 480 ft, and constructing the leaves in the open position kept the channel open for shipping. Because the new piers and open leaves are well outside the channel markers, it is felt that the waterway is now reasonably collision-proof. Details of the design and construction are summarized. The design of the bridge is earthquake resistant.


  • English

Media Info

Subject/Index Terms

Filing Info

  • Accession Number: 00624088
  • Record Type: Publication
  • Files: TRIS, ATRI
  • Created Date: Aug 28 1993 12:00AM