Featured Movable Bridge Projects
Cianbro replaced the 80‐year‐old Gut Bridge, a bobtail swing bridge in South Bristol, ME connectingRutherfo rd Island to the mainland, with a single leaf bascule bridge. This project was constructed in twophases: (1) Installation and removal of several cofferdams of varying sizes and construction of retaining wallsto 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.
Cianbro performed this work in a tight work area, 80 ft by 100 ft. 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.
2017 ENR New England Best Projects Merit Award & Safety Merit Award 2017 Roads & Bridges Top 10 Bridge (No. 8)
I‐695 Curtis Creek Bridges Rehabilitation
Cianbro was awarded the Curtis Creek Bascule Bridges Rehabilitation on the I‐695 beltway in Baltimore, Maryland through a Construction Manager at Risk (CMAR) contract with the Maryland Transportation
Authority. Cianbro will be performing rehabilitation on the span drive, tail lock, and central lock machinery, in addition to many electrical modifications and upgrades.
Cianbro is performing work within a very tight 11‐month construction schedule. Another challenge will be replacement of the machinery. The machinery will need to be installed in the exact location as the original
machinery, meaning the existing anchor bolts, which are several feet long, will need to be tested and reused if possible. With limited access to the machinery, Cianbro will utilize a barge and crane to remove and replace
the major component. The project will be completed in two phases, which will entail outer and inner loop closures based on where the work is being performed.
North Hero – Grand Isle Drawbridge
Cianbro is constructing and replacing the US Route 2 Bridge over Lake Champlain, connecting the two islands of North Hero and Grand Isle, located in Vermont. It is the only working highway drawbridge in Vermont and
the only vehicular connection between North Hero and Grand Isle. The bridge consists of a double leaf bascule span and will be replaced on‐line with a similar double leaf bascule bridge, so that the historic
elements will remain.
Any bridge closure will create a 90‐mile detour for all vehicular traffic, even emergency vehicles. As a result, Cianbro is using Accelerated Bridge Construction methods in order to maintain at least one lane of traffic.