Shotcrete was used for the restoration of the Spokane River in Spokane, Wash. The contractor used Shotcrete MS-Fiber Reinforced Concrete by Quikrete Cos. to fill channels and create weirs to help return the Spokane River to its natural flow pattern in downtown Spokane. Prior to the restoration, that section of the river was mostly empty during hot, dry months as a result of man-made channels dating back more than a century.
“In the late 1800s, channels were created at the bottom of the Spokane River to divert water from stagnant pools in the city’s downtown area to mills using hydropower,” says Don Dodroe, regional sales manager for Quikrete Cos. “While the channels did relieve many of the pools, they also prevented the Spokane River from flowing properly, which basically left the riverbed empty each summer. By building concrete weirs to redirect the flow, the contractor was able to spread water over a larger portion of the riverbed. However, the challenging terrain required the use of material that could be applied in tight spots at long distance and manipulated to match the surrounding landscape, which is why our shotcrete was chosen.”
The undulating riverbed is 150 feet deep and 300 feet wide in some areas, so the Shotcrete was pneumatically pumped dry through a hose to each predetermined weir location, in some cases more than 500 feet. Water was then added to the mix at the nozzle during the spray application process. This minimized material waste, created a consistent application, and made the process extremely mobile, according to the shotcrete contractor. In addition, the shotcrete was customized to match the color, texture, and shape of the natural basalt riverbed, as well as the surrounding geology and landscape. The American Society of Landscape Architects recognized the Spokane River Restoration with an award in 2012 and described the project as, “an excellent improvement to the river, producing an enjoyable amenity for the community and improving river flow and fish passage.”
Shotcrete MS–Fiber Reinforced is a single-component, micro silica-enhanced repair and restoration material that achieves more than 9000 psi compressive strength at 28 days, and features very low rebound and permeability characteristics. The Quikrete Cos. offers a full line of shotcrete products that can be applied through a wet or dry process to deliver high-strength, high-adhesion, low-rebound, and low-sag in rehabilitating bridges, tunnels, parking garages, ramps, piers, dams, and other concrete structures. In the past decade, shotcrete has been used on renovation projects like the Stanford Linear Accelerator in California, the New World Symphony in Florida, and the Ashton Hydro Electric Plant in Idaho.