SEPTEMBER 2020, VANCOUVER, BC: The North Shore Wastewater Treatment Plant (NSWWTP) is a new facility that will offer environmental benefits and additional community amenities in addition to its sewage treatment function. Located on Vancouver's North Shore, the facility is capable of treating 102 million litres/day under normal conditions and up to 320 million litres/day when storm water enters the sewer system in wet weather.
The new plant will be built to Leadership in Energy and Environmental Design (LEED) standards on a very compact site. With challenging conditions, including a location that had limited access with accelerated pour schedules, the Lafarge team was the ideal option to provide both performance and materials supply. The digester hopper, a portion of the plant, presented unique placing and finishing challenges. The pour was anticipated to take up to 16 concurrent hours. As well, the structure had to be watertight, with low shrinkage qualities in the concrete. The structure was built with dense rebar and formwork sections, with formwork installed during the pour. Therefore, the concrete had to set quickly in order to support the next lift.
Fortunately, Lafarge's WCAN Technical & Development teams - located across Western Canada - have the facilities, equipment, and expertise to develop custom mix designs that can meet these conditions and specifications. As a result, Lafarge provided a 14mm mix design that included a shrinkage-reducing admixture, successfully used in an earlier wasterwater treatment plant project. To further ensure that the accelerated mix utilizing our value added offering QuickSet had enough acceleration to support subsequent lifts, and to ensure there was no extra strain on the formwork during placing - Lafarge assisted in timed mockup samples to confirm performance.
The final product: a continual 28-hour pour that met the project's exacting specificiations, accommodated last-minute formwork changes, and value added offerings. Lafarge's combination of engineering capabilities paired with high performance materials ensured that the North Shore Wastewater Treatment Plant is anticipated to meet its LEED requirements utilizing a 50% SCM "Green" design for this structure, and assist Acciona in meeting its opening deadline.