Cianbro

Scope Of Work

Cianbro replaced the 80-year-old Gut Bridge, a bobtail swing bridge in South Bristol, ME connecting Rutherford Island to the mainland, with a single leaf bascule bridge. This project was constructed in two phases: (1) Installation and removal of several cofferdams of varying sizes and construction of retaining walls to serve as the abutments for the temporary bridge and (2) Installation of a temporary bridge, demolition of the existing bridge, installation of new bridge abutments, bridge substructure and superstructure, bridge machinery, and bridge control house, and removal of the temporary bridge. 

Project Details

Installed seven very complex cofferdams (one with double walls, many with complex tie back systems) for a total excavated quantity of 2,027 cubic yards

Constructed retaining walls and abutments concrete 1,714 cubic yards

Set 128 tons of bridge steel

Constructed a two-story bridge control house

Ran 33,000 linear feet of electrical cable

Installed 35 Rock Anchors

Constructed 900 linear feet of composite timber fender systems

Lean, Innovative, and Unique Project Solutions

Cianbro performed this work in a tight work area, measuring 80 feet by 100 feet.  Live traffic existed on one side and power lines on the other. There were residential buildings on all four corners of the bridge. Some of the cofferdam sheet installation work had to be done within inches of residential structures. The team was also challenged with the tidal zone schedule. The tidal shift in this area was as much as 14 feet. On any given day, crews would have as little as 30 minutes to access the work, while at other times there would be 4 hours of access for the shift to work. Every minute was carefully planned. The project team successfully worked within the project in water work windows and prescribed channel closures to open the bridge and channel to the community on schedule.

Awards

2017 ENR New England Best Projects Merit Award & Safety Merit Award

2017 Roads & Bridges Top 10 Bridge (No. 8)

2018 NSBA National Prize Bridge Award Winner