Manitoba Floodway Expansion Project Bridge Replacement

The Red River Floodway around the City of Winnipeg was constructed in the 1960s as a result of a major flood event in 1950, which required the evacuation of over 100,000 people, flooding of 10,000 homes, and damages in excess of $75.0 Million. The original Floodway is 29 miles long with an average bottom width of 450 feet, flow depth of 30 feet, and design discharge of 60,000 cfs. Six highways and six railway lines cross the Floodway. In 1997, the third largest Red River flood in recorded history passed through Winnipeg with a peak flow of 140,000 cfs. Approximately one half of this flood was diverted through the Floodway. A post-1997 study recommended increasing the Floodway capacity from 60,000 cfs to 140,000 cfs, which has a major impact on the six major highways and six rail lines. A pre-design study of all highway and railway bridges was undertaken in 2003/2004 and included load rating and life cycle costing analysis. The study results recommended the replacement of all highway bridges and one railway bridge and the raising, lengthening, and retrofitting of five railway bridges. Estimated construction costs of the bridges and related roadworks is $225.0 M. The final design and construction began in 2005 with Dillon Consulting Limited as the lead consultant in association with EarthTech; ND LEA; UMA, and Wardrop. All the highway bridges are either 6, 7, or 8 spans. All spans utilize 2000 mm deep, 43.5 m long, prestressed precast concrete Nebraska University (NU) girders. Concrete decks are continuous for live load and utilize Glass Fibre Reinforced Polymer (GFRP) reinforcing bars for negative moments. One structure (the TransCanada Highway) will have remote sensors installed, and its performance will be monitored by ISIS. Prior to final design, an extensive life cycle study of deck systems was undertaken which examined several different types of reinforcing and deck construction alternatives. The paper will elaborate on the overall design and mitigation of environmental impacts of all six highway bridges. The six railway bridges are owned by four different authorities: two – CNR; two – CPR; one – Central Manitoba Railway (CEMR); and one – Greater Winnipeg Water District (GWWD). All bridges utilize steel deck plate girders with the exception of the GWWD bridge which is precast prestressed concrete girders. For the most part, the railway girders are utilizing the existing substructure units, which will be retrofitted to accommodate new superstructures. The superstructures will all be replaced with ballasted steel through plate girders, which will provide additional hydraulic capacity with only minimal adjustments to track profiles. Unlike the highway bridges, each of the new and retrofitted railway bridges has a unique design, which will be elaborated in the final paper. A unique feature of the railway portion of the project is that three of the bridges will require temporary detour structures. Staging of the railway bridges has been set so that the new girders for the CEMR bridge will be fabricated first and used in sequence as the superstructure for the detours at three other bridge sites. The overall Floodway Expansion Project, including the bridges, is scheduled for completion in 2010.