Devil’s Slide Tunnel and Bridge
Located along the coast between Pacifica and Montara, the Devil’s Slide portion of Route 1 has had a history of road closures due to rockslides and land slippage since its construction in 1937. Today’s multi-phased project included the construction of twin tunnels that allow motorists to bypass these major slide areas. The tunnels are about 4,100 feet long, 30 feet wide, 22 feet high and 60 feet apart. The project scope included roughly 225,000 cubic yards of excavation and 80,000 cubic yards of tunnel concrete. The project also included twin bridges spanning a valley. The two bridges are concrete, cast-in-place, segmental bridges. The bridges themselves are made up of more than 13,3000 cubic yards of concrete, plus 1100 cubic yards of concrete for the footings. To address the challenging environmental and site restrictions, Central Concrete established a portable plant on the job site.