The Construction of the Montmorency Forest GMAW-Welded Aluminium Deck on Steel Girders Bridge

WSP was responsible for the design and detailing of Canada’s first GMAW-welded aluminium deck on steel girders bridge for Université Laval. The firm developed welded aluminium panels connected by blind bolts and supported by three steel girders. The 15 m by 8 m structure was fully preassembled for quick onsite installation and designed to support both highway and forest truck loads. Amid post-pandemic procurement and welding challenges, the fabricator, designer, and owner worked closely together throughout construction. While the project experienced delays, quality was prioritised, culminating in a pioneering structure for Canada. This paper explores the construction process, including trials to optimise the 28 mm deep GMAW welds. The fabricator developed an innovative approach for positioning removable backing bars within 10-metre-long hollow extrusions. Non-destructive testing was essential due to the absence of detailed acceptance criteria in current standards. Post-welding deformation control was achieved through several iterations and the post-heating process. The bolting plate method effectively joined hollow aluminium components, and custom features were incorporated to accommodate Université Laval’s research instrumentation.