Replacement of Culvert with Pre-Cast Concrete Arch Bridge
The Town of Manchester retained Weston & Sampson to complete survey, wetlands delineation, soil borings, design, permitting, and bidding for the replacement of the culvert on Edgerton Street. The replacement of the culvert provides an opportunity to open up a pedestrian corridor from Broad Street to the Center Springs Park with the installation of a new pre-cast arch bridge. This project includes the replacement of the stone culvert with a 3 x 5 box culvert and the installation of a new BEBO concrete arch bridge. A structural evaluation of the existing culvert was completed to determine if the new culvert could be installed while leaving the existing culvert in place. Once the project is complete, the old culvert will be abandoned.
The existing dam, culvert, embankment and channel were not properly represented with the existing FEMA mapping and related cross sections. This resulted in a number of problems related to permitting and also raised questions of how to analyze flows. A meeting with CTDEEP and the Town was conducted to decide how to handle these differences in the FEMA modeling and related calibration of any modeling of the impoundment. Verification of the 100-year flood elevation in the impoundment along with the resulting outflow is critical to sizing of the piping and the overall solution. The existing dam and related structures were evaluated and inspected as part of the Dam Safety Permit to ensure that additional problems were not present around the dam.
As part of the final design, Weston & Sampson will submit a Dam Construction Permit application to the CTDEEP, and a U.S. ACOE Category 1 Permit to the Town of Manchester Planning and Zoning Commission/Inland Wetlands Agency. During the permitting phase, there was extensive communication among the agencies, town staff, and resident groups so that everyone was kept informed of all developments that arose. This type of communication allowed for a smooth design process.