Major Breakwater Repair in the Azores: Fid-Bau Portal

Major Breakwater Repair in the Azores

Miller, Ann B. / Kahler, Richart / Werren, David J. / Kenny, Thomas F.

The breakwater, at the Military Port that services the Lajes Field Air Base, located on Terceira Island, Azores, protects the Main Fuel Transfer Facilities in this Port. This breakwater is directly exposed to Atlantic Ocean waves arriving from the east. Originally constructed in 1961, the breakwater has been extensively damaged over the intervening 40 years with near breaching in December 2001. This paper provides a summary of a phased repair strategy that preserved pier operations and allowed the development and implementation of a permanent solution. This project has demonstrated an effective approach to the repair of a severely damaged rubblemound breakwater, employing a hybrid solution using both CORE-LOC® armor units and an armor stone berm. Emergency repairs to stabilize the breakwater immediately adjacent to the fuel pier started in October 2002 and continued through 2003. Development of a more permanent design solution for the breakwater was initiated in 2004 and continued through 2008. The project posed significant challenges, including: (1) Limited funding for repair. The rehabilitation of the structure had to be conducted over several years due to limitations on annual funding, necessitating a phased approach to construction. (2) The long-term degradation of the breakwater over its entire length. (3) The problem of stabilizing any repair section within the damaged structure. (4) Limited construction period due to the North Atlantic storm season (November through March). (5) Limited information of wave environment. The "hybrid" CORE-LOC®/armor stone structure was selected as the preferred alternative. The cross-section consists of a 30 meter wide berm of armor stone at the toe of the CORE-LOC® armor layer. The berm is constructed of 5 to 20 tonne stone along the trunk and 10 to 20 tonne stone at the head, and has a crest elevation of+3 m (MLW).