TYLin provided design services for the Tsable River Bridge, which opened as one of the largest single-cell box structures in North America.
The Tsable River Bridge is 400-meter-long, four-lane highway bridge that crosses the environmentally sensitive Tsable River Valley 60 meters above the valley floor.
Because the bridge is located in an area of seismic activity, TYLin took great care to reduce the weight of the superstructure as much as possible. The single-cell box girder configuration eliminated the need for a central web wall, minimizing the amount of concrete needed to construct the bridge.
Minimizing environmental impact also played a key role in determining the structure type. TYLin engineers found that the simplified single-cell design allowed construction to take place at the top of the gorge. This avoided compromising old-growth trees on the valley floor and damaging the salmon-rich river below.