Project Summary

The Cheshire Toll Bridge (NHDOT Br. No. 135/052) carrying NH Route 11 over the Connecticut River was constructed in 1930 and is comprised of Pennsylvania steel through trusses spaced at 24’-6” with west-, center-, and east-span lengths of 153’-6½”, 169’-2” and 166’-6”, respectively. The overall length of the bridge is 500’-7”. Unique to the bridge is the north and south trusses, consisting of different member sizes due to prior trolley use on the northerly side of the bridge. 

Our NBIS-certified inspector leads a bi-annual routine and fracture critical inspection of the three bridge spans and completed a detailed inspection report under an on-call complex bridge contract with NHDOT. During the inspection a boat mounted inspection vehicle was used, enabling inspectors to access the lower portions of the truss, and floor framing without any impact to traffic. Boat access reduced inspection time compared to traditional equipment, as equipment did not need to be maneuvered through truss members. The upper bracing and upper portions of the truss were accessed utilizing a lift on the bridge, while one lane of alternating two-way traffic was maintained. The information obtained was also utilized as part of a detailed load rating of the bridge that Hoyle Tanner completed under a separate contract.