Sentry Bridge at Watkins Glen State Park

sbp is the project lead for the replacement of the historic pedestrian bridge at the entrance of Watkins Glen State Park. Currently spanning the gorge is a concrete arch bridge with stone veneer built in 1908. Although the existing bridge has become a symbol of the park, time and harsh weather have worn away the bridge’s supporting abutments, making a full replacement necessary. The new Sentry Bridge design is a lightweight evolution of the former arch bridge. Alluding to the curved form of the previous bridge, the half-arch design disappears behind the rocks, leading visitors into the park’s mystical Gorge Trail that lies beyond. For the new bridge, special consideration has also been given to the design of a new landmark structure that does not disrupt the gorge’s natural features or fragile ecosystem.
The new design also takes into account the unstable rock conditions and future weathering at the abutments. Given the poor condition of the southern abutment, a solution was needed where more of the bridge’s load could be carried by the northern abutment. Under normal conditions, the bridge is designed as a single-span girder supported by the south and north abutments. However, in the case of a failure at the southern abutment, the bridge can act as a cantilever, supporting itself solely on the north abutment.
Construction sequencing for the bridge was also considered early in the design process due to the bridge’s difficult to access location. The bridge will be lifted into place in one piece, allowing for a shorter construction time and less disturbance to the site. Creating a shorter construction timeline was also desired by the client to minimize the amount of time the trail will be closed to the public.