Alcatraz Island Cliff Stabilization

The National Park Service is evaluating options for protection and preservation of cultural and natural resources at one of its most popular parks. Natural erosion of the cliff face over time is encroaching on the historically significant features of the former prison site. The Langan team performed a 3D laser scan of the cliff face at the island's southern end. The scan provides a baseline of the existing condition as well as detailed imaging and linear information used to evaluate the structure of exposed rock. Our recommendations included combinations of steel rock bolting and face treatment via high-strength steel mesh netting and shotcrete. The cliff stabilization was carried out in two phases during which we provided construction administration and quality control services.