Slope Stabilization at Devil’s Slide: DSI protects Highway from Landslides

Ever since its inauguration in the 1930s, California highway 1 has been damaged on a regular basis by landslides and rock slides at Devil’s Slide near San Francisco. Nevertheless, the road is very popular due to its location directly along the pacific cliff line and is universally considered as one of the most scenic roads in the world.

Consequently, slope stabilization measures were begun on Highway 1 in order to maintain the future stability of this route even though a tunnel is being constructed that will redirect the major part of traffic around Devil’s Slide region.

The fact that Highway 1 is very popular with cyclists was one of the crucial factors in the decision to maintain the road serviceable in the future. Cyclists will continue to use the old highway along the cliff line once the bypass tunnel is completed. By separating motor vehicles from bicycles, a higher degree of safety is ensured for all road users.

Additional reasons for maintaining the old route after the completion of the bypass tunnel were its attractiveness for tourism as well as the availability of an alternative route in case of high traffic volumes. Due to the fact that Devil’s Slide is situated in a highly corrosive environment because of its proximity to the ocean, DSI USA used Double Corrosion Protected (DCP) Multistrand Tieback Anchors for stabilizing and repairing the slope after the latest landslide. A total of 184 type 9x0,6" Multistrand Anchors in average lengths of 42.7m were used for emergency repair.

Thanks to the excellent co-operation between all parties involved, repair work on Highway 1 could be completed quickly and safely.