Constructed in 1951, the John Greenleaf Whittier Bridge is currently in the process of being replaced by a new bridge compliant with current safety standards. The high traffic bridge connects Newburyport and Amesbury via I-95 over the Merrimack River.

Constructed in 1951, the John Greenleaf Whittier Bridge is currently in the process of being replaced by a new bridge compliant with current safety standards. The high traffic bridge connects Newburyport and Amesbury via I-95 over the Merrimack River. Walsh Construction is employing a rail mounted gantry crane system to simplify the placement of the steel bridge girders and precast deck to create the approach spans. Two 6 foot tall, 960 foot long temporary support steel box girders will be launched across temporary piers to create a rail system for the gantry crane to operate on during the approach span construction. The steel box girder arrangement will be moved after the placement of each approach span. It’s critical that the two 550 ton temporary steel support box girders move in unison in order to prevent binding or misalignment of the gantry crane operating on top of the rail system.