As a part of ongoing management of the City of Edmonton’s bridge inventory, three bridges in the environmentally sensitive River Valley were identified for rehabilitation in 2011 and 2012. These include: Grierson Bridge (a four-span voided slab structure), MacDonald Drive Pedestrian Underpass (a single-span waffle-slab buried structure) and Rossdale Bridge (a three-span solid slab structure).
The City’s objective was to extend the service life of the structures by 20 to 25 years. Associated Engineering was retained to provide a condition assessment, rehabilitation design and resident engineering services during rehabilitation construction of these bridges.
The Rossdale Bridge, a three-span 48 metre long reinforced concrete bridge constructed in 1957, was identified for a condition assessment due to the poor condition of the superstructure. It was found that the deck concrete had high chloride levels, well in excess of the corrosion threshold for steel in the top 110 millimetres. The strategy adopted for rehabilitation comprised of removal of the top 175 millimetres of concrete by hydrodemolition, installation of new stainless steel reinforcing over the piers, conversion of the abutments to semi-integral, and a new high performance concrete overlay complete with waterproofing and an asphalt wearing surface.