The Boston Central Artery included many viaducts and ramps, divided into multiple manageable and coordinated construction contracts. The segments were erected using both the balanced cantilever and span-by-span methods. The project included the I-93/I-90 Interchange, Southbound Viaducts, and Ramps, consisted of 1,900 ft. of segmental concrete ramp structures integral to the I-90 mainline through Boston. It also included: 1 ramp of precast segments erected using a span-by-span method with overhead gantry (approximately 84 segments) and 2 ramps of precast segments erected using a balanced cantilever method (approximately 120 segments).
A 2003 National Finalist in the Engineering Excellence Awards from the American Council of Engineering Companies, these multi-level ramps and viaducts efficiently move 200,000 cars daily into and out of Boston’s “Big Dig. The $187 Million project features the tightest curvature of any precast concrete segmental bridge in America with horizontal curve radii down to 212’. The total bridge deck area is 520,000 square feet. Spans ranging from 100’ to 200’ were built in span-by-span and balanced cantilever construction over numerous active railroad lines and roadways.
The Big Dig combines the Central and Southbound Central Artery, along with the Leonard P. Zakim Bunker Hill Bridge, Leverett Circle Connecter Bridge, and the Ted Williams Tunnel which is considered to be one of the most technically-challenging infrastructure developments and ever undertaken in the US.