Lougheed Highway Pedestrian Overpass replaced in two hour night closure

Above: Completed structure, insert: New span being placed, close to completion with access platforms still in place

On Tuesday, July 19, 2005, a truck struck a pedestrian overpass on Lougheed Highway at Dewdney Trunk Road in Coquitlam, B.C. The impact caused the 33 metre long bridge to collapse, damaging the single prestressed concrete girder beyond repair.

The City of Coquitlam retained Associated Engineering to design a replacement for the overpass. The new structure had to be designed and constructed as quickly as possible. Since the City had limited funds for this unforeseen bridge replacement, cost of the structure had to be kept to a minimum.

The City wished to retain undamaged portions of the overpass, such as the ramps. Associated Engineering developed a design using a galvanized Pony-truss for the main span replacement. This design allowed the vertical clearance to be increased by more than 600 millimetres, with no modifications or replacement of the approach ramps. The handrail elevations were maintained thus maintaining the overall aesthetics of the structure. By simplifying the truss details, construction cost was kept to a minimum.

The steel structure is significantly lighter than the original concrete girder, thereby improving the seismic response and reducing the foundation loads.

The new main span was placed by crane within two hours during a night closure. “It was a late night (early morning) for all, with the new aesthetically pleasing structure up in an hour and a half, fitting to within millimeters of the design specifications and well within our tolerance levels,” advised construction inspector, James Nikolai.

Associated Engineering staff involved in the project included Leslie Mihalik (Project Manager), Stephen Pienaar, Francois Atkinson, and James Nikolai.

Going to Fort McMurray

In 2004, Brybil Projects, an affiliate of Associated Engineering, and Kiewit Management Company, completed design and construction of the McKay River Bridge for Canadian Natural Resources Ltd. (CNRL). Located 500 kilometres north of Edmonton, the new bridge and roadworks provide access to CNRL’s new Horizon mine site. The McKay River Bridge is a 262 metre long, fivespan, two-lane bridge designed to carry 800 tonne overload vehicles, among the heaviest vehicles to travel on Alberta’s roads.

In January 2006, the McKay River Bridge faced its heaviest load: an 800 tonne coker. The photo shows one of four cokers that crossed the bridge in January. These cokers are the heaviest loads that will cross the bridge. See AE Today 2005 Issue 1 for more information about the CNRL McKay River Bridge.