Replacement of Whittier Bridge over Merrimack river

Steere Engineering was responsible for designing the multi-functioning precast pier base panels associated with Piers 1 & 2 of the Southbound Bridge. The Whittier Bridge carries I-95 NB & SB over the Merrimack River between the cities of Amesbury and Newburyport, Massachusetts. The structure has a total length of 1300 ft consisting of three (3) approach spans and a 480 ft main span network arch.

The multifunctioning precast panels served as support for the granite clad finish, formwork for the pier bases and cofferdams which aided in the construction within the river. Pairs of opposing panels were connected on a barge using bracing frames and struts. The partially assembled pier base panels were then lowered around the micro-pile foundation template. This process was repeated until the outer shell was complete.

Following completion of this outer shell, a concrete tremie seal was poured forming a watertight base which could then be dewatered. Upon dewatering, the rebar cages were set, and the pier base concrete was poured completing the pier bases within the river. In addition to the design of the panel bases, Steere Engineering was also responsible for additional temporary works including formwork and shielding designs.

Location: Amesbury-Newburyport, Massachusetts

Owner: Massachusetts Department of Transportation (MassDOT)

Timeline: Design Completed in 2015; Construction Completed in 2016