Halifax Harbour Bridges or HHB is responsible for constructing, operating and maintaining transportation facilities crossing Hailfax Harbour in Nova Scotia. This includes two suspension bridges and their approaches – the Angus L. Macdonald Bridge and the A. Murray MacKay Bridge. HHB is currently undertaking a redecking of the suspended spans of the Macdonald Bridge and has retained Buckland & Taylor, Ltd. to design the new deck. Due to the complexity of the project, HHB has retained the services of Ammann & Whitney as an Independent Check Engineer (ICE).
The Macdonald Bridge spans Hailfax Harbour and connects Hailfax to Dartmouth. It is comprised of a 762m (2,500’) suspension bridge with a main span of 441m. It was completed and opened to traffic as a two-lane bridge in 1955 with a single sidewalk. In 1998-99, an additional sidewalk and bikeway were added, the orthotropic deck was replaced and a vehicular travel lane was added. The deck constructed at that time is being replaced again.
Because of our expertise in the design and maintenance of long span bridges, Ammann & Whitney was added to the team to ensure that the design is constructible and to confirm that the structure is never overstressed at any stage of the construction process. Since the bridge must be open to traffic during normal weekday hours, we are also charged with ensuring that the bridge geometries are always maintained in smooth, drivable conditions. A computer model, utilizing our in house designed program, BRIDGES, will be developed to verify the bridge response at every stage of construction.