Detroit International Bridge Company
Ambassador Bridge: Harsens Crossing

West of Algonac to Harsens Island, New York

Preliminary design of a bridge across the north channel of the St. Clair River from just west of Algonac to Harsens Island. The bridge will provide two traffic lanes with a raised sidewalk and bike lanes and crosses the channel at a slight skew to allow adequate connections to the existing roadway network.

The preliminary design of the bridge includes 12 fixed spans having span lengths of 146 feet and a 130 feet single leaf bascule span. The fixed span superstructure will include a cast-in-place concrete bridge deck constructed composite with four precast, prestressed, concrete beams per span. The fixed span superstructure is supported on concrete hammerhead piers supported on four 84 inch diameter drilled shafts over 150 feet in length due to very poor soil conditions.

The single leaf steel bascule is mechanically driven with electric motors and includes a bascule and fixed pier as well as a control house. The design of the substructure for all elements required structural capacity in challenging soil conditions to withstand the large ice forces in the river. Project also includes the design of a toll facility, approach roadway, preparation of an environmental assessment, permitting and coordination with the United States Coast Guard, Michigan Department of Transportation and other regulatory authorities. As part of the environmental assessment, a HEC-RAS model originally developed by the United States Army Corps of