Watson Generating Station - Braintree, Mass.
As the signature of Boston’s Big Dig project, the Leonard P. Zakim/Bunker Hill Bridge (Zakim Bridge), completed in 2002 and fully opened in 2004 is not only the world’s widest asymmetrical cable-stayed bridge, but it is also the first asymmetrical cable-stayed bridge in the nation. The bridge, which spans from Boston’s North End to Charlestown, MA, consists of ten lanes, and merges I-93 and U.S. Route 1 traffic across the Charles River, into and out of the Thomas P. O’Neill Jr. Tunnel.
The bridge design is comprised of the hybrid composition of steel in the 745-foot main span and concrete in the bridge back spans, supported by the two, 270-foot inverted Y- shaped towers. The installation presented unique challenges throughout the construction process. One major challenge was having to build the bridge within a busy transportation corridor, consisting of the existing I -93 highway and the Massachusetts Bay Transportation Authroity’s Commuter Rail, subway and bus systems, all of which had to operate continuously and seemlessly during construction.
MEC was responsible for the bridge’s aesthetic lighting, lighting protection, navigation guides and interim power for construction. The work included the installation of over 100,000 feet of conduit and more than 200,000 feet of wire. Over 100 metal halide flood lights, of up to 1000 watts each, wash the structure with blue and white light.
The Zakim Bridge is impressive as an entrance to Boston for drivers coming down from the North, and has become a New England landmark. At night, the lighting effect is nothing short of spectacular.