The New Old Bridge: Renovation of the Macdonald Suspension Bridge

摘要

The Angus L. Macdonald Bridge crosses Halifax Harbour in Nova Scotia. The existing deck is being replaced because it has reached the end of its service life. The design of the new superstructure and its replacement sequence were completed in 2013. The contractor is now replacing the entire suspended structure and hangers sequentially during night and weekend closures while the bridge is kept open for daytime traffic. The effects of the erection sequence on bridge behaviour are supported by sophisticated automated erection analysis models which account for the geometry of the existing bridge, positioning of the erection equipment on the deck and necessary hanger and strand jack adjustments that are required during construction to prevent overloading of the structure. The design involved significant wind tunnel testing and analysis to ensure aerodynamic stability during erection and in the final condition.