Ruck-a-Chucky Bridge
Auburn, California, 1978 (project not completed)
Design Team: Skidmore, Owings, and Merrill, T.Y. Lin International
Architect: Myron Goldsmith
Structural Engineer: T. Y. Lin
Civil Engineer: Hanson Engineering
Material: Concrete and steel cables
Structural system: Concrete box girder with cable-stayed support system
Maximum span: approx. 1,100 ft.
In 1978, SOM architect Myron Goldsmith and engineer T.Y. Lin designed a bridge to span the middle fork of California’s American River. The bridge was to carry a local intercounty road across the river once a new dam was constructed, increasing the span to 1,100 ft. The curved shape was selected to minimize deep cuts and tunnels that would have been required to build a straight bridge. Intermediate piers were avoided by using a “hanging arc” form comprised of a curved box girder that carries the traffic and tensioned cable stays. High strength cables were anchored to the steep hillsides and post-tensioned in such ways to control the stresses in the girder. Steel and concrete solutions were both considered for the girder, as they were considered very close in cost at the time. Lightweight concrete was ultimately favored to reduce cable weight and cost. The curved design was tested, and found effective in dealing with earthquakes and high winds. However, when the dam construction halted, the project stopped.
