The Regional Municipality of Wood Buffalo engaged Associated Engineering to design a new pedestrian bridge crossing the Hangingstone River in Fort McMurray, AB, at the south end of the municipality. The existing steel truss road bridge carrying King Street over the river was overloaded by an unattractive, painted timber pedestrian, single direction walkway. The existing coating system on the structure was also suffering from extensive deterioration.
For the structure’s design, timber was identified during the preliminary design phase, both as a cost-effective option, as well as an appropriate fit with the natural environment of the river, park, and walking trails. The new bridge uses 2 metre deep glued-laminated, timber girders as the main structural members spanning the river. Timber was also used for the stringers and most of the floor beams.
The design features a half-through girder structural form on a shallow curve, with the main load-carrying members doubling as the parapets. This provides a modern, low profile crossing that fits gently into the landscape, and minimizes the depth between the top of the deck and the underside of the structure. Minimizing the structural depth was important, as the bridge had to be raised to meet current regulatory requirements.
Other notable design characteristics include multiple visible openings in the girders to break up the solid face of the structure, and allow pedestrians to look through and out at the river. Stainless steel plates along the top of the girders offer protection to the timber and adds a visual interest. At night, handrail lighting focuses the light onto the deck, which enhances user safety and reduces light pollution. The light also shows through the