8 Arch Bridge Committee Finalizes Construction Plan
At its March 21, 2017 meeting, the committee completed its plans to stabilize the bridge and make it safe for use as part of the rail trail.
Once work on the bridge is completed, the remaining portion of the old rail bed can be resurfaced from Central Street to the Sherborn Line.
Daniel Crovo, above, of Gill Engineering, attended the meeting to answer questions from the committee about his work on the project to date. Gill Engineering produced a report detailing proposed construction to stabilize the bridge and make it safe for users of the rail trail.
The work, as proposed by Gill, and agreed to by the committee, includes removal of the deteriorated concrete coping (the concrete visible along the top edge of the bridge), replacement of the concrete end posts which have failed and are visibly sagging, installation of new coping and concrete decking designed to stop water from leaking into the bridge and creating a surface appropriate for pedestrians and horses (the surface used on the rest of the trail will not be needed), and a pedestrian railing similar to the one shown below.
Jay Robinson, chair of the committee, and the other committee members have decided not to address the non structural issues of the bridge such as replacing grout (the mortar between the granite blocks) lost due to water infiltration from the deteriorated deck, cleaning the face of the blocks or removal of the efflorescence created by the water leaching through the grout. Gill's estimate of the cost for the work is $300,000 for the structural work and $160,000 for the railing system. Gill has also submitted a proposal to prepare final plans and specifications for the proposed work, including managing and overseeing the construction.
Committee member Alison Lima, above, prepared a spreadsheet detailing the work and associated cost for the CPC (Community Preservation Committee) review of an application for CPA (Community Preservation Act) funds to pay for the work. Alison's request includes a 30% bidding contingency resulting in a request totaling $590,000, including $62,000 for plans and specifications and construction management.
The CPC will review the application at its next meeting on March 27, 2017. The application requests that the structural work be funded under Historic Preservation and the pedestrian railing be funded under Recreation/Open Space CPA funds.
After the meeting, Robert Weidknecht, above, and Herb Brockert, below, presented the proposed work to the Conservation Commission for approval under an Order of Conditions. In order to protect the stream that runs under the bridge and the associated wetlands, the work will be completed entirely from the rail bed.
BTW, the 8 arch bridge is the local name for the Bogastow Brook Viaduct.