C1 - Boston Central Artery

Notice to proceed for Boston’s first segmental bridge project was given in January 1997 to Modern Continental Construction for their low bid of $108.6 million, of which about 20% is for the segmental superstructure. The superstructure is substantially completed and the entire project is scheduled to be complete in September of 2001.

The C09C1 viaducts extend in a north south direction from the I-93 Mass Avenue Interchange to Charlestown’s Sullivan Square. The superstructure consists of two parallel box girders over most of the 1820-ft. length, and three box girders at the south end where Ramp AS (Albany Street) will provide access to I93SB in its final configuration. The box girders are typically connected by a 2-ft. wide longitudinal reinforced closure joint. The spans vary from 110-ft. to 206-ft., with span lengths dictated by the existing urban conditions. The longer spans at the north end of the project utilize a Type 2 box girder with the depth varying from 7-ft. to 10-ft. at the piers.

There are four distinct phases for erection of the superstructure, each separated by demolition of existing structures and construction of temporary structures.