Super•Cor Low Profile Arches, Stabilized Earth Walls, Kleinberg, Ontario
The Canadian Pacific Railway (CPR) faced a challenge when creating a grade separation for trains and trucks heading in and out of their intermodal yard in Kleinberg, just 15 minutes north of Toronto’s Pearson International Airport. The solution was a two-lane service road for trucks and an overpass for trains, all in the same yard. CPR chose two engineered Super•Cor steel structures to carry the loads of their heavy and frequent trains over the service road.
Extreme load, high water table, low height of cover
Coupled with the need for strength was the need to build the grade separation without disturbing the water table, which meant engineering two very strong buried arch bridges, each with a very low height of cover – only 55 inches. AIL designed the Super•Cor bridges to withstand Cooper E-80 live loads, which easily supports the total weight of trains (5,350 tons). The design load presented by the trains is 4.2 times more severe than the Ontario highway design load, the heaviest in Canada.
Our flexibility helped keep the project on schedule and on budget
While CPR knew that a concrete bridge might be an option, the initial bid from The AIL Group was more attractive. The field engineer for Hatch Mott MacDonald – CPR’s contracted engineering firm – observed that the Super•Cor bridges were performing as intended six months after installation. On a recent check ten years later, they are still quietly living out their long, low-maintenance service lives without incident.
Our initial quote was for one buried arch bridge with a 44.3' span, a 19' rise, an 82' length and up to 8.2' of soil on top. When we were asked to respond to the actual tender, new rules needed to be applied to conform to the height restrictions and actual drawings, elevations, and field geometry. There was also a requirement for two buried arch bridges instead of one. The span of each structure was 51' and the rise was 15.7'. One of the bridges was 45' long and the second, 85'. Like all Super•Cor, the CPR bridges came in small, lightweight pieces that were easy to transport and assemble.
To try to stick to our original budget, we recommended shortening the structures with vertical Stabilized Earth Walls for headwalls. Despite all of the accommodations that needed to be made, the projects were finished on schedule. The assembly of the two structures began on July 18 and the track was open to train traffic on August 20.
Encased Concrete Ribs added strength for extreme loading
Reinforcement of Super•Cor is not usually required, but with the extreme loads that CPR required the bridges to handle, AIL designed the ribs to be filled with concrete under the railway loading. The construction of the Super•Cor bridges began with the casting of concrete footings for each structure. Once the footings were complete, the structure was assembled in place, arch pieces bolted together, and the Encased Concrete ribs poured in place. The finished product combines the lightweight and tensile strength of steel with the compressive strength of concrete.
The end treatment for the structures was Stabilized Earth Walls (Wire Wall), a welded wire mesh with a front face of 48''x 24''. The Stabilized Earth Walls provided a fast, flexible, and long-lasting solution.