Batchawana, Ontario - New Wharf Construction:
Riggs Engineering was retained by Small Craft Harbours to redesign and supervise the reconstruction of both the outer and inner legs of the Batchawana Bay wharf. This structure is on the shoreline of Lake Superior at Batchawana Bay, approximately 72km north of Sault Ste. Marie, Ontario.
The original outer leg consisted of timber decking supported on timber stringers, pile caps and piles with bracing between the piles for lateral restraint. The inner leg consisted of timber decking supported on stringers, pile caps, piles and continuous closed face timber piles. The outer leg had suffered severe deterioration.
Riggs Engineering redesigned the wharf with vertical steel H-piles, steel sheet piling and a timber superstructure. Finite element analysis was used to design each structural component of the wharf. The initial design of the new wharf included battered piles; however since they produce large uplift forces from ice impact, the design was changed to vertical piles. Since vertical piles do not provide sufficient lateral restraint, an additional pile cap was introduced which runs perpendicular to the frame. Moment connections were designed at all pile cap locations. This system provided better lateral restraint and smaller uplift forces. The H-piles were driven to stiff, silty clay to provide sufficient bearing so that settlement of the structure, due to live load, does not occur and to acquire adequate skin resistance to prevent uplift.