Glenmore Causeway Improvements

The Glenmore Causeway Upgrades (GCU) included the removal and reconstruction of the existing Causeway Bridges to support the expansion of Glenmore Trail and satisfy current flood control guidelines through the causeway for the Glenmore Dam. Glenmore Trail is a main continuous East-West route through south Calgary with over 140,000 vehicles per day and is located only 500m upstream of the Glenmore Dam and Water Treatment Plant intakes. To satisfy not only the traffic requirements but also the water passage capacity for the reservoir, the construction involved the removal and replacement of the existing bridges, widening the causeway, and construction of a new bridge for an adjacent ramp. In addition, the contract included the upgrading of the West Glenmore Storm Pumphouse. These projects were required to allow for the realignment of Glenmore Trail and the completion of future Glenmore Corridor Upgrades east of the Causeway.

The construction of the new bridges was completed in several stages to not only limit impact to the traffic but to also avoid constraints on reservoir storage. Stage 1 had minimal impact on traffic as the work zone for the ramp bridge occurred off the roadway to the north. The ramp bridge was constructed first to provide additional roadway for detours in future stages. Construction of this bridge also required that the existing pedestrian pathway be closed and detoured. Stage 2 involved the removal of the existing Eastbound Causeway Bridge on the south side of the project followed by the construction of the new Eastbound Bridge. This stage permitted the westbound bridge to remain in use to maintain the same number of traffic lanes. The final stage, Stage 3, was the removal and reconstruction of the Westbound Causeway Bridge. Again, the number of traffic lanes were maintained by placing traffic on the new Eastbound Bridge and the new ramp bridge with work occurring between the two bridges. At this stage, the recreational pathway was re-opened on the south side of the new Eastbound Bridge. The bridge removal of both the existing Eastbound and Westbound Causeway bridges required stringent environmental measures to be implemented. To minimize the potential for debris falling into the reservoir, the bridge deck was saw cut and removed in pieces instead of more traditional demolition methods. In addition, falsework was installed on the lower flange of the existing steel girders to catch any debris or deleterious fluids that might have slipped down from the deck. Additional measures including silt fencing and containment systems were also implemented for the demolition of the existing abutments. Graham went to extensive measures and expense to salvage the existing 43m x 1.8m structural steel girders from the demolished bridge structures. Installed in 1963, they were in excellent condition and to this day continue to be used as temporary works on Graham projects, keeping with Graham’s commitment to sustainability in construction. Bridge components were consistent across all three bridges and included precast concrete NU girders, cast-in-place substructures, galvanized reinforcing steel and driven steel piles for the foundations. Additional works included cast-in-place traffic barriers, roadworks, landscaping, and reinstating the recreational pathway on the south side of the Causeway. The Causeway Upgrades also involved alteration of the West Pumphouse to accommodate the new road. The pumphouse is part of the Causeway storm drainage system and operation of the system was maintained throughout construction to mitigate risks associated with water or hydrocarbon spills entering the reservoir from the active roadways. Demolition and removals at the pumphouse included one-third of the pumphouse structure including walls, roof, and slab as well as demolition of existing manholes, storm mains, and traffic barriers. Concrete, masonry, metal, and electrical work were performed to construct the new pumphouse building envelope. Upgrades and re-alignment of the storm water lift station at the reservoir were also completed. To complete the removal and re-alignment of the storm main, storm water was temporarily pumped from a dammed manhole to the pump house grit separator.