Rehabilitation of the Orient Point Lighthouse Foundation

The Orient Point Light, constructed in 1899, is located in Long Island Sound, approximately 0.4 nautical miles northeast of Orient Point, Long Island, NY. The Light marks the end of Oyster Pond Reef on the western side of Plum Gut where heavy currents make navigation difficult. The Light is owned and operated by the US Coast Guard - Aids to Navigation Team, Long Island Sound. The Orient Point Light is comprised of a tower section (brick lined cast iron plate construction), a base section that is a concrete filled cast iron caisson, associated boat landing structures and a perimeter of riprap armoring. During an above and underwater investigation conducted in February, 2008, the concrete filled circular base of the Orient Point Light was found to be in serious condition. The 1-1/2 inch thick cast iron caisson panels were found to have failed and the interior concrete fill was severely deteriorated. The failure along the south face of the caisson resulted in a reduction of the caisson's structural capacity. Repair of the lighthouse foundation presented several challenges: difficult environmental conditions such as high currents and waves; access only via water-borne equipment; and historic structure restrictions. To meet these challenges, the repair needed a visual appearance similar to the original cast iron base; needed to be constructible in the difficult conditions of Plum Gut; and needed to restore the structural capacity of the caisson. This paper will outline the site investigation requirements and design approach to overcome these challenges, as well as a description of construction aspects of implementing the repairs.