Unprecedented growth in Port Coquitlam, Canada, led to a larger population, increased business activity and a pressing need to address higher traffic volumes. More than ever, drivers needed an efficient way to cross the Canadian Pacific Railway (CPR) yard that divided the city’s north and south.
The City of Port Coquitlam awarded us the contract to design and build an overpass to facilitate the movement of people and goods over the Canadian Pacific Railway yard. This contract included full engineering and construction responsibilities as well as temporary works and traffic management, environmental engineering, communications and project management.
Designing around technical constraint
Our design-build team was tasked with finding a solution that was suitable for the extraordinary construction constraints and logistical challenges posed by this project. Crossing an operational rail yard meant that pier locations were predetermined and ground access would be severely restricted during construction. Local soils were soft and compressible with clay extending up to 30 metres below ground. Additional project challenges included dealing with contaminated soils, substantial utility impacts, requirements to provide environmental enhancements and managing existing traffic on the heavily congested existing roadway. Finally, we had to take into account an ambitious schedule that called for the entire structure to be open to traffic within 24 months.
Our solution was a unique cable-stay design with integrated construction and fabrication methods. A 580-metre, 4-lane cable-stayed bridge was designed to be push-launched over the active rail yard from the south end. This design/construction methodology resulted in a solution that optimized efficiency for both the temporary construction and final configurations—and most importantly, it allowed the bridge to be erected safely with minimal impact on the operations of the rail yard. The twin steel box-girder structure was launched simultaneously, further reducing the construction schedule, and the permanent cable stays were used to help support the structure during the launch. At the time, this was the longest push-launch process successfully attempted in North America.
Working in and around an operational rail yard
An in-depth understanding of switchyard operations and rail car vulnerability was required to effectively plan work schedules and phases. By sequencing all construction stages carefully, SNC-Lavalin made sure that CPR operations were not affected by the construction, and that all of their assets and personnel were kept out of harm’s way. Meticulous planning, execution and teamwork led to the project being delivered on time and on budget.
The Coast Meridian Overpass project has earned numerous awards, including:
- 2011 Award of Merit, Consulting Engineers of British Columbia
- 2011 Award of Excellence, Canadian Consulting Engineer magazine
- 2012 Honor Award, American Council of Engineering Companies
- 2012 Awards of Excellence, Canadian Consulting Engineer magazine