High Steel fabricated 1,100 tons of steel for the new 426-foot arch bridge connecting Chesterfield, NH and Brattleboro, VT on Route 9 over the Connecticut River. The bridge was constructed adjacent to the existing 1937 historic steel arch bridge, which remains in place for pedestrian use.
In total, the new bridges’s arch ribs consist of eighteen 43-57’ curved box sections weighing up to 35 tons each. Twenty-eight hangar assemblies with four wire ropes each suspend the roadway superstructure from the steel ribs.
To avoid impacting the waterway during the erection of the bridge, the contractor, Cianbro, constructed a temporary support structure consisting of two 110 foot temporary steel towers at each abutment. Wire ropes and an anchoring system were used to tie back the towers during the erection of the steel arch ribs from barge–mounted cranes.
The bridge construction was completed in October 2003.
Bridge Type: Arch
Steel Tonnage: 1,100 tons
Steel Type: Grade 50
Project Owner: New Hampshire Department of Transportation
Designer: New Hampshire Department of Transportation
Steel Fabricator: High Steel Structures Inc.
Steel Erector: Cianbro