Alcatraz Island

   In the early 1900’s Alcatraz Island was used as a military prison and sits approximately 1.5 miles offshore within San Francisco Bay. In the 1930’s, the military prison was converted into a federal prison and was operational until 1963. During the 29 years operating as a federal prison, there were several high-profi le criminals who served prison time there such as Al Capone, Machine Gun Kelly, and Whitey Bulger.

   In the early 1970’s, Alcatraz Island was opened to the public as a tourist attraction and now sees over an estimated 1.5 million visitors per year. Denso was asked to provide several SeaShield™ products to repair 111 piles on the Alcatraz Wharf Repair Project. Both the General Contractor and the Dive Contractor elected to work with Denso as they had successfully installed several SeaShield Systems on numerous projects in the past and were very pleased with the performance and ease of installation.

   Denso’s SeaShield Series 500™ was used, as well as a version of our Series FX-70™, in conjunction with a rebar cage. The SeaShield Series 500 was selected for piles that exhibited some sign of slight degradation, but ultimately were deemed structurally sound, to provide a long-term durable system for corrosion prevention. The 550™ Epoxy Grout, used within the Series 500 system, is an extremely fl owable and pumpable high strength epoxy grout that will fi ll in any small voids and/or cracks that may be present.

   The SeaShield Series FX-70 was used on piles that were deemed no longer structurally sound. The components of the FX-70 System (SeaShield FiberForm™ Jacket, SeaShield FX-225™ Cementitious Grout, and SeaShield 550 Epoxy Grout) were used in conjunction with rebar to provide a full structural repair to these piles. All SeaShield Fiber-Form Jackets on this project were manufactured with a black fi nish to minimize visibility.