Stay Cable Vibration Testing at the Leonard P. Zakim Bunker Hill Memorial Bridge

The Central/Artery/Tunnel (CA/T) project cost roughly 15.6 billion dollars and is the largest public works project in the history of the United States. The project originated as a result of traffic forecasts for Boston, Massachusetts indicating that by 2010 there would be at least 16 hours per day of stop-and-go traffic along Interstate 93. In addition to traffic congestion, the existing Interstate 93 elevated roadway effectively separated the North End and Waterfront areas from the remainder of the city. Planning for the CA/T project started in the 1980's with construction starting in 1991. Construction was substantially complete by 2007. The two primary objectives for the project were the relocation of the Interstate 93 underground and the extension of Interstate 90 east to Logan Airport. In order to meet these objectives, the CA/T project included a massive amount of infrastructure including on-grade roadways, bridges, tunnels, buildings, and ancillary structures. In all, the project included about 7.8 miles of highway. In order to support the physical structures, the project also included extensive electrical, mechanical, and communications systems. The scale of the CA/T project has been compared to construction of the Panama Canal, English Channel Tunnel, and Trans-Alaska Pipeline.