The I-90/Route 1A Interchange includes six elevated concrete viaducts and ramps designed by GM2’s Complex Bridge team. The interchange, located near Logan International Airport, is part of Boston’s Central Artery/Tunnel Project and provides a key link between the new Third Harbor (Ted Williams) Tunnel, Logan Airport, the City of East Boston, State Route 1A and the existing Sumner/Callaghan tunnels running under Boston Harbor. The structures total 4,890 linear feet and are multicell post-tensioned concrete box girders cast-in-place on traditional falsework, with a total deck area of 212,474 square feet. Bridges vary from three to seven spans with total lengths between 481’ and 1,142’. All viaducts are 6’-6” deep with spans ranging from 123’ to 180’. Cast-in-place post-tensioned concrete construction allowed for the complex roadway geometry necessary in this challenging area.

The I-90 viaducts represent the eastern terminus of this important interstate highway. The sixth and final viaduct on the project was opened to traffic in May 2005 marking completion of all bridge work. In addition to interchange reconstruction, the project features new roadway connections, two new parks, a new light rail station, and a new stormwater management system for the City of East Boston and Logan International Airport