The bridge's rising costs of upkeep and maintenance, as well as local traffic delays due to frequent repairs, eventually led to the decision to replace the structure with a wider, reinforced concrete bridge 1500 feet upriver. The project also will incorporate new features into the structure, including bikeways and a fishing pier. Total construction is estimated at $230 million.
Construction on the new bridge began in mid-2007. Building the two bascule piers proved to be a major challenge on the project—the two matching bascule piers range from 50 to 75 feet tall at various points.
In addition to the overall size of the concrete placement, most of the construction had to be conducted in the water. Equipment had to be barged to the jobsite, causing numerous access issues.
Placing the concrete for the control house also was a challenge for the construction team. This part of the project includes an 8-foot-wide concrete deck extended from the vertical surface of the structure that is 50 feet in length.
The general contractor Cianbro/Middlesex opted for Doka forms to help meet the various project challenges.
Support frames were used to form the bascule wall's cantilevered concrete. Various spindles and channels helped to create different angles required on the project.
Kaven Philbrook, project manager for the bridge, chose Doka's A Frames to assist in the concrete placement. Mounted to the structure's surface using fabricated heads and anchors, these frames serve to support the cantilever.
More than 30,000 square feet of Framed Framax Xlife Formwork, 100 18-foot-long MF 240 climbing platforms, and several custom fabrications were used to form this large-area project.
Because of its easy use, the form-work system is flexible enough to meet the demanding forming needs of the project. The system can be quickly and safely stripped, enabling faster reset and setup for the next casting. Standard components also were used in unusual combinations, conforming to the bridge's unique design. This also allowed for adaptation as conditions changed from pour to pour.
Doka provided the equipment preassembled nearby and sent by barge directly to the jobsite. Cianbro/Middlesex was able to pick up the formwork and set it in place.
The bridge is expected to open in the autumn of 2012.
For more information on Doka formwork, visit www.dokausa.com.