27 June 2012
The Minnesota and Wisconsin departments of transportation have picked HDR, working with Buckland & Taylor, to design the St Croix Crossing Bridge.
The bridge will span the St Croix River between Oak Park Heights in Minnesota and St Joseph in Wisconsin.
Figg Bridge Engineers, Parsons Transportation Group, TY Lin International and URS Corporation were also in the running for the contract.
The US$14.2 million contract will develop the extradosed-type design that was selected by a community stakeholder group. The design is a hybrid of a concrete box girder structure and a cable-stayed structure. It is designed to minimise environmental impacts by keeping tower heights below the river bluffs and reducing the number of piers in the river. When completed, the St Croix Crossing will be the second extradosed bridge in the United States; the first is currently being constructed in Connecticut.
The bridge is estimated to cost between US$280 and US$310 million and will be constructed using the design-bid-build method. The bridge is a part of the larger St Croix Crossing project, which includes expressways on either side of the bridge in Minnesota and Wisconsin. The project also includes an extensive trail facility for pedestrians and bicyclists, as well as historic and environmental mitigation work. The total cost for the entire project is estimated at between US$580 and US$676 million.
The design work will take approximately one year to complete with construction of the bridge anticipated to begin in autumn 2013.