The Niantic River Bascule Railroad Bridge, which connects the towns of East Lyme and Waterford, CT, is located on the main line of Amtrak’s Northeast Corridor between New York City, NY and Boston, MA.
Hardesty & Hanover performed the new bridge design: an off-line replacement of the aged existing structure that involves a two-track, single leaf bascule bridge to be constructed 58 feet south of the existing railroad alignment. Besides the movable bridge span and counterweight tower span, there will be a 65-foot-long west approach span, and a 130-foot-long east approach span. The entire length of the bridge, abutment to abutment, is approximately 375 feet. The track horizontal alignment and profile provides for a design speed of 90 mph on the west approach and 80 mph on the east approach. H&H developed a unique structural system comprised of separate counterweights integral with each of the main bascule girders in order to eliminate complex and costly devices associated with the overhead catenary system during bridge openings.
In the open position, the bridge provides a 100-foot-wide navigation channel with a 75-foot minimum vertical clearance, with unlimited vertical clearance for an 80-foot width. In the closed position, the bridge provides 16 feet of vertical underclearance to mean high water, a more than four-foot increase over the existing bridge condition. A composite materials fender system borders the channel to provide protection from navigation strikes to the bridge piers.
The bridge replacement was part of a major realignment of the railroad. H&H was prime consultant managing the design of the construction of approximately one mile of new, two-track, overhead catenary system electrified railroad. The approach construction included several thousand feet of retaining wall and 100-year storm scour protection. The project also provided replacement of an existing town boardwalk and extensive replenishment of a sand beach on a salt-water bay of the Long Island Sound. Federal and state environmental permits as well as US Coast Guard permits were obtained for the work, and protection of a beach plant “Species of Special Concern” was included with the project. The bridge and beach officially opened on June 7, 2013.