Photo courtesy County of Santa Barbara, Dept. of Public Works

The Gibraltar Road Tire Anchor Wall project in Santa Barbara, Calif., was recognized with an Award of Merit from ENR California's annual Best Projects competition.

Photo courtesy County of Santa Barbara, Dept. of Public Works

Used automobile tires were recycled for a retaining wall to stabilize the slope below Gibraltar Road in the mountains above Santa Barbara.

Heavy rainfall during January 2005 saturated a cliff below the road, washing out the soil and removing part of the surface. The $90,000 project was constructed in two weeks during October 2008. The tire-anchor wall contains 280 tires of various sizes, arranged in 14 vertical layers. Sand backfill was placed between each row of tires to fill any air voids. Each tire is tied to the next with polypropylene rope.

After a wildfire singed the wall in 2011, the contractor returned in October of that year to apply a wire mesh and shotcrete for protection against damage from future fires.

Key Players

Owner: County of Santa Barbara, Dept. of Public Works, Santa Barbara

Contractor: Tierra Contracting, Santa Barbara

Lead Design: County of Santa Barbara

Highway and Street Construction: Nye & Nelson Construction, Ventura

Drill Rig: Javier’s Construction, Oxnard

Submitted by County of Santa Barbara, Dept. of Public Works