Mystic River Bascule Bridge

Electric motors raise the Mystic River Bascule Bridge by driving large bull wheels linked to the two plate girders of the lift span, while concrete weights at the ends of the overhead rocking trusses counterbalance the bascule span through another set of linkages. This configuration was patented in 1918 by New York City consulting engineer Thomas E. Brown. The bridge has a channel width of 74 ft. 6 in., a channel depth of 20 ft., a movable span length of 85 ft., a total bridge length of 218 ft., a roadway width of 33 ft., a clearance over the roadway of 18 ft. 8 in., a tower height of 33 ft. 9 in., a total bridge height of 44 ft. 6 in., a movable span weight of 664 tons, and counterweights of 285 tons each. Its average opening time is 7 min., with about 2200 openings per year. From 2000 to 2013, the bridge underwent a two-phase rehabilitation intended to restore long-term reliable operation. The first phase began in 2000 and included replacement of the open grid steel deck system and sidewalk decking, along with structural repairs to the concrete counterweights, sidewalk supports, and pier substructure. The second phase began in 2010 and included complete replacement of the operator’s house, operating machinery, and electrical control systems, as well as repairs to the structural steel and painting of the superstructure. The work was carefully designed to match the historic character of the original bridge, including lowering the electric motors into machinery pits beneath the pedestrian sidewalks in accordance with the original 1920 design, and was successfully completed in April 2013.

Mystic, Connecticut · United States