Engineers Week: Sibley Pond design/build bridge replacement project
Even Tropical Storm Irene couldn't keep bridge builders from finishing a Pittsfield, Maine, project 10 months ahead of schedule.
The Sibley Pond Bridge was the first design of the Precast/Prestressed Concrete Institute (PCI) Northeast Extreme Tee (NEXT D) type precast/prestressed double T-beam section with a full-depth integral deck.
The section had been newly developed by PCI Northeast in response to the Federal Highway Administration's (FHWA) nationwide initiative for accelerated bridge construction. The NEXT D beam was considered advantageous because it included opportunities for additional economy, speed of erection, and potential for enhanced durability to meet the owner's 100-year life requirement. The team's technical proposal was judged by the Maine Department of Transportation to offer the best value and was also the lowest bid for replacing the existing bridge.
Parsons Brinckerhoff, a national engineering and design consulting firm with a local office in Manchester, N.H., has been involved in a wide range of engineering and construction management projects throughout New England, including current work on the I-93 widening project from Windham to Manchester. The firm completed design-build for the Sibley Pond Bridge. using
accelerated project delivery, state-of-the-art concepts, and utilization of innovative Accelerated Bridge Construction (ABC) techniques.
The 790-foot-long, two-lane Sibley Pond Bridge is located along Route 2 between the towns of Canaan and Pittsfield, Maine, and was opened to traffic on Nov. 21, 2011, more than 10 months ahead of the owner's scheduled project completion date of October 2012.
A gantry crane moved each 70-ton beam into place, taking two days per span, enabling the contractor to open the bridge on schedule, despite serious beam delivery delays from the precaster's shop in Middlebury, Vt., resulting from Tropical Storm Irene.
The bridge design was constructed in 15 months by Lane Construction Corp. as part of a design-build project. The 10-span bridge (two five-span continuous units) has fixed abutments at each end with flexible intermediate piers allowing only one expansion joint in the middle of the bridge.
The contractor elected to move Route 2 traffic onto a temporary detour roadway. The alignment followed a former roadway which was built on corduroy timbers across a peat bog. Crane mats were used to mimic the colonial era corduroy construction method in areas where the detour road was wider than the existing road. With traffic safely relocated, the contractor was able to use the old bridge for construction access.