Scope of Work
Cianbro constructed a new 426 ft steel arch bridge.
- Constructed the project adjacent to the existing historic steel truss bridge that will remain in place for pedestrian use
- Realigned 4,200 ft of Route 9
- Blasted 8,500 cy of rock to construct the west (VT) abutment and wingwalls
- Constructed a 61 ft by 73 ft sheet pile cofferdam with a soil-anchored tie-back system to construct the east (NH) abutment and wingwalls
- Drove 132 pipe pile and placed a concrete mat footing to construct the NH abutment
- Constructed a temporary support structure by erecting two 110 ft temporary steel towers at each abutment—using wire ropes and an anchoring system to tie back the towers—to erect the steel arch ribs
- Erected 1,100 tons of structural steel including eighteen 43 to 57 ft sections of steel arch ribs weighing up to 35 tons each
- Installed 28 hangar assemblies—four wire ropes each—to suspend the roadway superstructure from the steel arch ribs
Lean, Innovative, and Unique Project Solutions
The Cianbro team designed an innovative, overhead, cable-stay temporary support structure to help erect the 43 to 57 ft sections of arch ribs weighing up to 35 tons each. Erecting the steel arch ribs from barge-mounted cranes, this unique overhead system avoided impacting the waterway.