Welcome to Caltrans District 4

Devil's Slide Project | Bridges

The Devil's Slide Project Bridges connect the north portal of each tunnel to Highway 1. Both bridges pass over a valley at Shamrock Ranch that contains a pond and wetlands. During construction, the wetland area was fenced off to protect an environmentally sensitive area.

Each bridge has a total length of approximately 1000 feet. Two sets of twin piers on each side of the valley produce main spans about 445 feet long. At the highest point the bridges are 125 feet above the valley floor and are curved to provide a smooth transition from each portal to the existing alignment of Highway 1.

Concrete box sections of the bridge were built out from each of the four piers. This technique is known as the cast-in-place cantilever method. It avoids building temporary support towers in the environmentally sensitive area of the valley during construction.

To provide a design that met with public approval and to compliment the natural surroundings, particular care was taken over aesthetics. For example, tapered piers and curved struts give a graceful shallow arch look to each bridge. An open design tubular steel pedestrian / bicyclist guard rail will preserve spectacular views from both bridges.


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