Fort Jefferson

Fort Jefferson is located in the remote Dry Tortugas National Park seventy miles from Key West. The mid-1800s masonry and coral concrete structure was constructed over 30 years and exemplifies the military architecture and civil engineering of its era. Over time, the fort’s saltwater environment resulted in corrosion and expansion of the embedded iron shutters at the small wall openings used to fire cannons. The movement of the iron in turn caused significant damage along the scarp wall; major sections of brick and mortar fell into the surrounding moat.

Responding to a possible need for emergency stabilization, TYLin conducted a program of archival research, testing, analysis, and monitoring to assess the fort’s structural behavior. As part of this work, TYLin developed a comprehensive model of a section of casemates from archival documents and targeted field measurement. The model was used to define the loads imposed on the deteriorated structure and was critical to guiding the analyses and communicating repair solutions. 

TYLin determined that emergency stabilization of the scarp wall was not necessary, allowing efforts to be directed towards targeted permanent repairs. The most recent completed phase of work fort entailed removing and rebuilding critical areas of the scarp wall, including replacing corroded shutters with non-ferrous material.

Tortugas Harbor Lighthouse: TYLin also worked on the design of repairs for the iconic hexagonal cast-and-wrought-iron lighthouse. Located on one of Fort Jefferson’s bastions, this 1876 lighthouse was originally known as the Garden Key Light. Initial work on this lighthouse included an in-depth structural assessment, evaluation of movement, and the design of a temporary scaffolding and shoring system to ensure the deteriorating structure’s stability during hurricane seasons. Subsequent work included development of construction documents for removal, off-site restoration, and reconstruction.