BETA was selected by MassDOT to complete the final bridge design of the Central Street Bridge over the Sudbury River. The bridge, and its unique location, not only play an important role in the local and regional transportation network but also assist with the mitigation of flooding in the Saxonville neighborhood of Framingham. The bridge sits just 40 feet downstream of the Saxonville Dam, a high hazard, 24-foot tall, 180-foot-long earthen and masonry structure, and the bridge’s substructure is an integral component of the US Army Corps Saxonville Flood Control Infrastructure.
The original 1930s concrete arch bridge was replaced in the early 1970s with a superstructure comprised of butted pre-stressed concrete boxes founded on concrete gravity abutments. With constant water spray from the adjacent dam, the superstructure quickly deteriorated and needed to be replaced. BETA was asked by MassDOT to complete and finalize the design of the replacement bridge. The new main span of the bridge over the Sudbury River consists of massive 93-foot-long, 5’-3” deep New England Bulb Tee girders each weighing a staggering 88,500 lbs. The crane used to erect the girders was colossal itself with a 60-foot x 30-foot footprint, a 158-foot tall towering boom, and 363,800 pounds in counterweights. The existing substructure elements are being rehabilitated to support the bridge.
Demolition and construction of the bridge required special measures due to its proximity to the dam and its integration into the flood control infrastructure. As such, the project required pre- and post-construction condition survey of the dam and floodwalls, dam and floodwall vibration and movement monitoring, and flood contingency planning in the event of large storms occurring during construction.