Publish and Present
The United States Coast Guard (USCG) Winter Moorings facility in Algonac, Michigan consists of a 200-foot long solid-fill wharf owned by the City of Algonac and leased by the USCG. The wharf, comprised of a steel sheet pile bulkhead and timber boardwalk, is used for supporting USCG Bay Class Ice Breaking Tugs to break up ice within the St. Clair River and Great Lakes. When not in use by the USCG, the deck area is accessible to the public as a portion of the Algonac Waterfront Park, which stretches approximately 2,500 feet along the river.
In Spring of 2013 the wharf exhibited a failure, resulting in substantial settlement of the bulkhead, timber boardwalk, and translation over the 200-foot length of the bulkhead. Investigations revealed that the failure was likely attributed to record-low water levels in the river combined with insufficient toe embedment.
Repairs for the bulkhead featured an aggressive design schedule which included a site investigation and failure determination, regulatory permitting, design analysis, and development of construction documents. The project also had a limited construction budget to minimize the USCG’s financial exposure for the leased property. To meet the budgetary constraints, alternative design approaches were implemented including re-use of suitable portions of the existing anchor system, non-traditional material selection, and a simplified berthing system.
This paper discusses the factors that led to the bulkhead failure; the innovative techniques used to efficiently evaluate the failure; the challenges associated with the design; and the design approaches used to meet the construction budget.