|State Street Bridge Reconstruction|
|Location: New Haven, CT|
|Tuesday, 20 July 2010|
This project, designed by DTC, is currently under construction and DTC is providing the Construction Phase Services. Funding is provided under the STP-Urban Program. The project involves replacing the existing two span concrete bridge with a single 80 foot span comprised of pre-stressed bulb-tee beams with a concrete deck supported by cantilevered abutments on concrete filled steel pipe piles. The bridge carries State Street over the Mill River, and one end of the bridge is under another bridge carrying Interstate 91. Two lanes of traffic must be maintained during the two stages of construction.
The challenges DTC resolved included installing new piles, and support of excavation, adjacent to the I-91 overhead bridge pier footing which is also founded on piles. The solution involved a combination of splicing piles and sheeting with shorter length units and re-adjusting locations in addition to requiring on-site testing and monitoring. As part of the design process, DTC also performed a detailed hydraulic analysis and scour assessment for this project. Considerable tidal influence severely affected flows through the existing bridge that caused scour issues to develop with the existing pile supported bridge foundation. A proposed bridge pile support system and riprap scour protection were recommended to protect the proposed bridge from further scour issues. DTC's hydraulic and scour analysis became an integral part of the Flood Management Certification process required for this project.