Mystic Movable Bridge Rehabilitation

Mystic Movable Bridge Rehabilitation (Stonington, CT)

Type: Single Leaf Brown Bascule
Location: Stonington, CT
Connecticut Department of Transportation

Stafford Bandlow Engineering personnel provided mechanical engineering services for the rehabilitation of this historic single leaf Brown bascule bridge from inception through completion. Services included a scoping inspection, complete rating of all mechanical machinery, development of a Bridge Design Report, preparation of plans, specifications, and cost estimates for the design of all machinery and construction services.

The design provides new span drive machinery to comply with current AASHTO requirements, improved efficiency, and reduced maintenance requirements. The scoping inspection identified major settlement of the substructure resulting in misalignment of the upper balance truss and span drive machinery relative to the bascule span. Design services expanded to include rehabilitation to correct this misalignment including replacement of the primary support components for the balance truss and the balance link components.

Design plans provided complete details of all mechanical components including the critical design of all base plates to ensure proper support for all mechanical components.

Construction services for this project were extensive and included partnering meetings, review of shop drawings, approval of machinery installation and alignment procedures, shop inspection, oversight of critical machinery alignment, approval of the entire mechanical installation prior to startup and oversight during the initial opening including the monitoring of the machinery loads.

The mechanical construction work was completed over two winter closure periods, and the bridge was opened on schedule at the end of each of the closures.