b'A TOWERING TASK Photos courtesy of PCL.Installed on a custom-built mid-river foundation, a tower crane is enabling vital structural repairs at Manitoba Hydros Slave Falls Generating StationBy Matthew BradfordRehabilitation work is ramping up atthe structure can operate as intendedCreating the cranes foundation was Manitoba Hydros Slave Falls Generatingand allowing the Slave Falls Generatingone of the most complex elements Station, where PCL Constructors CanadaStation to remain in operation. of the project. Measuring 34 feet in Inc. is preparing to launch Phase Two RAISING CRANE height and 20 feet in diameter, it was of the sites large-scale concrete founded on rock in the middle of the repair initiative. The rehabilitation has been tenderedsluiceway, downstream of Pier 5.The project involves restoring andin two phases. The first, completed byOne of the considerations for the strengthening several concretePCL last summer, involved infrastructuredesign team was designing the components throughout the stationsupgrades to support the permanentfoundation to withstand full sluiceway seven-bay sluiceway structure,rehabilitation work. This included theoperations without restricting including its piers, rollways andinstallation of a tower crane foundationwater flow, explains Brad Mackid, concrete walkways and roadways. Itin the middle of the Winnipeg Riverconstruction manager at PCL.also includes the installation of steeland the erection of a tower crane confinement plates around the existinglarge enough to lift and install keyEnvironmental and safety piers to preserve their current conditioncomponents (i.e., steel confinementconsiderations were key to the and the construction of downstreamplates, formwork and reinforcing steel)foundations installation. Because across the entire sluiceway work area.the process involved the tremie pier extensions to enhance structuralCrews also constructed upstream andplacement of concrete into the water, stability. The overall goal is to stabilizedownstream boat launches to allowpH levels were monitored outside this critical facility after nearly a centuryaccess for diving teams supporting theof the formwork to prevent high-pH of exposure to water flow, ice andongoing rehabilitation. water from being displaced into cycles of freezing and thawing from thethe surrounding environment. PCL Winnipeg River. The erection of the tower crane waswas also responsible for pumping The scope of the Slave Falls seven-baya critical milestone, says Maloney.displaced water into tanks and sluiceway rehabilitation project is toThe roadway crossing the seven-bayensuring it was transported off site for address and improve the structuralsluiceway has loading limitations dueproper treatment.integrity of the spillway, which is nearlyto the current structural condition of theSafety considerations also took priority. 100 years old, says Rick Maloney,existing piers. The tower crane enablesWorking in and around water meant team leader of the Generation Projectsthe construction team to limit heavystrict adherence to the Manitoba Department at Manitoba Hydro. Allloads on the roadway while maintainingWorkplace Safety and Health Act. rehabilitation work is critical to ensuringaccess for site operations. Additionally, safety measures were 44 BUILD MANITOBAwinnipegconstruction.ca'