Located in the heart of Edmonton’s River Valley, the Duggan Bridge replacement included the construction of a semi-integral, single-span bridge designed to grow with the city while offering spectacular sights to the surrounding community.
The project’s proximity to a highly populated residential area and several large buildings required our team to work carefully to ensure that construction did not impact the surrounding infrastructure. Mitigation efforts included building a retaining wall to minimize the impact on existing buildings. To improve overall slope stability, cast-in-place fillcrete thrust blocks were installed underneath the crane outriggers, resulting in a stable concrete base that improved safety for the crane operator.
Installing thrust blocks to stabilize the platform prevented the need for a larger crane or significant earthwork modification – work which netted significant cost savings.
With supply chain issues causing a delay in the installation of the steel girders, the project team recuperated lost time through prefabricating formwork for the concrete bridge deck. Concrete was readily available, and access to a local supply made it the ideal material to use during pandemic constraints.
The semi-integral bridge design also eliminated the need for steel deck expansion joints, which are challenging to install, need regular checks and cleanups, and feature a rubber that wears over time and can require replacements every 15 years. The result is a value return for the City of Edmonton, with cost savings in both construction and long-term maintenance.
The team incorporated new materials and technology to extend the bridge’s lifespan from an initial 65 years to at least 75 years. The materials included using high performance concrete on the bridge deck. The team recognized that high performance concrete can be difficult to finish and obtain an expertly sealed concrete surface. To eliminate any potential issues, the team researched various products and used spray-applied surface densifier which uses liquid silica to densify the top layer and improve the concrete surface quality while helping to finish and seal the concrete. The solution resulted in fewer surface cracks and reduced the need for epoxy injections after the pour. The product added value and cost savings for the client by improving the concrete quality.
PCL completed the Duggan Bridge replacement project six months ahead of schedule and provided the City of Edmonton with significant cost savings while delivering the surrounding communities safe access to the site's stunning views. An innovative approach, incorporating high-performance concrete and prefabrication, allowed the team to manage schedule risks and deliver a high-quality product.