Failure Investigation and Rehabilitation of a Steel Sheet Pile Bulkhead

The United States Coast Guard (USCG) Winter Moorings facility in Algonac, Michigan, consists of a 200-foot (61-meter) long solid-fill wharf owned by the city of Algonac (City) and leased by the USCG. The wharf, comprised of a steel sheet pile bulkhead and timber deck, is used for supporting USCG 140-foot (43-meter) Bay Class Ice Breaking Tugs to break up ice within the Great Lakes and inland waterways. In spring of 2013 the wharf suddenly failed, resulting in substantial settlement of the bulkhead, deck, and backland area, and translation over the entire 200-foot (61-meter) length of the bulkhead. The repair project for the bulkhead featured an aggressive schedule to restore operations to the facility and had a limited construction budget to minimize financial exposure for the leased property. To meet the budgetary constraints, the USCG used an innovative design which included the re-use of suitable portions of the existing anchor system, non-traditional material selection, and a simplified mooring and berthing system. This paper discusses the factors that led to the bulkhead failure; the techniques used to efficiently evaluate the failure; the challenges associated with the design; and the design approaches used to meet the construction budget.