CT's Historic Masonry Arches


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Mystic River Bridge,
Bridge No. 362


Mystic River Bridge, Groton-Stonington


Route 1 over Mystic River
Groton - Stonington
Steel balance-beam (Brown patent) bascule
Length: 4 spans, 223' overall, 85' bascule span
Built in 1922
Thomas E. Brown, engineer
American Bridge Company, fabricator


'Bull wheels' of the Mystic River BridgeFew bridges are as much fun to watch in operation as the Route 1 bridge in Mystic, because unlike many bascules, its mechanical parts are all out in the open. Power to raise the bridge comes from electric motors, which drive large "bull wheels" connected with linkage arms to the two plate girders which make up the lift span. Huge concrete weights at the ends of overhead rocking trusses counterbalance the bascule through another set of linkages.

This configuration was patented in 1918 by New York City consulting engineer Thomas E. Brown. Besides being economical to build, the design had many advantages: accessibility of major parts for maintenance, automatic Date plate on Mystic River Bridgebraking of the bridge at the top of its movement, latitude for imprecise motor control, and distribution of the bridge and counterweight forces onto separate piers. It also suited its setting well, since the low level of the crossing relative to high tide would have made it difficult to put the mechanism and counterweight below the road. The project immediately won high praise for Brown's design, and Mystic River Bridge was featured in several engineering journals and textbooks of the period.

Upgrading Route 1, the road along Connecticut's shoreline, was the top priority of the Connecticut Highway Department following World War I. This bridge was one of the last links in that effort.

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