The new I-91 Brattleboro Bridge located in Brattleboro, Vermont, replaced twin existing bridges over the West River with a new sustainable long-span landmark bridge. The best value selected, design/build project was designed by FIGG Bridge Engineers, Inc. and built by PCL Civil Constructors, Inc. for the Vermont Agency of Transportation (VTrans). During development the overall bridge was considered in relationship to its surroundings. Every view of the bridge mattered and was a part of the holistic design approach that was in harmony with the environment.
The new gateway bridge features a 1,036’ long arching concrete bridge soaring 90’ above the West River and was built using balanced cantilever construction. Two piers flank the riverbanks to support the three-span bridge.
It was important to VTrans and the surrounding communities that the new bridge serves as an icon and a gateway to Vermont. The bridge construction also needed to have minimal impact on the traveling public using the bridge, as well as those traveling under the bridge: vehicles on Vermont Route 30, kayakers on the beautiful West River, and hikers on the West River Trail.
This postcard worthy bridge features viewing platforms for pedestrians, hikers, and visitors at the base of each pier overlooking the West River and mountainous valley. True to its theme “A Bridge to Nature,” every detail of the uniquely shaped superstructure, piers, viewing platforms, and the railings complements Vermont’s natural landscape. The piers feature Vermont-inspired stone-formed and stained concrete that blends with the local environment.
The focal points of the bridge are the quad-wall piers, which emerge from the ground in sweeping organic forms and support the arching concrete spans. The quad-wall system of the piers provides stability and allowed the bridge superstructure to be built from above using balanced cantilever segmental construction without temporary falsework in the river. This scheme minimized the impact of the project on the environment and protected the West River and West River Trail.
VTrans required a 100-year design life, but the bridge designers focused on providing an even greater sustainable 150-year design life. Concrete segmental bridges as a structure type are inherently durable due to sustainable materials used and the use of biaxially post-tensioned concrete.
Compared with its predecessor, the new I-91 Brattleboro bridge provides a smaller overall footprint. With fewer footings and abutments, the new bridge better preserves and protects the environment below. A best-value concrete segmental solution provided a one-of-a-kind gateway to nature in the beautiful state of Vermont.