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OCTOBER 2017 | 83 Mechanized River Valley Access Project RENDERINGS COURTESY DIALOG Mechanized River Valley Access Project by ZUZANNA WODZYNSKA T his fall, after a year and a half of construction, the citizens of Edmonton, Alberta, and their visitors will be able to enjoy the latest addition to their city: an installation that combines esthetics with function, and provides pedestrian connectivity between the downtown core and the river valley below. It is currently referred to as the Mechanized River Valley Access (MRVA) project. "It's a big structure that doesn't look like an industrial application," states Jesse Banford from the City of Edmonton, which undertook the project on behalf of its citizens along with the River Valley Alliance. "As a collaborative team, we've worked hard to fulfill accessibility needs and make this a destination point as well." The North Saskatchewan River that winds its way through the City of Edmonton has an 88-kilometre network of trails that is separated from the downtown core by a steep slope. "The MRVA design is simple and undeniably powerful," says Donna Clare from Dialog's architecture team. Dialog provided mechanical, structural and electrical engineering services for the project, as well as architecture and landscape architecture. "It's an engaging narrative of connection between the natural and urban setting." From the city, the journey starts at the base of the iconic Fairmont Hotel Macdonald with a funicular transporting the public to the midway point of the slope. "It's one of only a handful of funiculars in the world that do not require an on-site operator to drive the car," notes Brent Carmichael from Doppelmayr Canada Ltd. The car can hold up to 20 people, travels at a maximum speed of two- metres per second, and its users maintain direction of travel when entering and exiting the cabin. This allows greater ease of use for anyone commuting with bikes, strollers or wheelchairs. "The funicular itself uses an innovative drive system that is essentially a large winch connected to a cable, pulling the funicular cabin up the hill," says Dialog's Sean Brown, project manager and structural engineer. "When the cabin is moving downhill, it rotates the motor and generates electricity, thereby lowering the energy usage overall." A set of nine-metre, multi-use urban stairs run alongside the funicular, with a runner's track and precast concrete benches to enjoy the view. "Downtown office workers have a place to enjoy lunch in the sun, while parents and children can engage in active play," notes Clare. "Visitors have a place to view and learn about the river valley and its role in shaping the capital city of Alberta." Both the funicular and the stairs end halfway down the bank. "A road network severs the river valley and the slope of the bank varies greatly from top to bottom, preventing the funicular and stairs from connecting directly to the valley floor," says Jeff DiBattista, project director for Dialog. "Instead, from the base of the funicular and stairs, users are lead past a public art installation, across a pedestrian bridge spanning the busy roadway, and finally to a glass elevator that completes the descent into the river valley." The end of the pedestrian bridge cantilevers about 20-metres past the elevator shaft to create a lookout point among the tree canopy, close to the river's edge. "Long cantilevers have their own design challenges such as increased vibration issues," notes Brown. "We made an allowance for tuned mass dampers to be added in case they were an issue for human comfort." The connection between the pedestrian bridge and the elevator shaft was also particularly complex. "The pedestrian bridge must expand and contract with temperature swings, resulting in the top of the elevator shaft moving along with the bridge," comments Brown. "As a result, the steel structure and the joints between the elevator glass cladding were designed to be flexible enough to accommodate this movement." Design, logistics and construction were affected by the site of the project as well. "The City of Edmonton understood that this application in a feature spot required innovation, LOCATION Grierson Hill, Edmonton, Alberta OWNER/DEVELOPER City of Edmonton ARCHITECT/ STRUCTURAL/MECHANICAL/ ELECTRICAL CONSULTANT/ LANDSCAPE ARCHITECT DIALOG CONSTRUCTION MANAGER Graham Construction & Engineering Inc. FUNICULAR DESIGN CONSULTANT Doppelmayr Canada Ltd. and Garaventa Group TOTAL SIZE 35,520 square feet TOTAL COST $24 million planning and careful co-ordination, and we were determined to assemble the highest expertise," comments Henry Maisonneuve, the project manager for the undertaking with the City of Edmonton. "We are in the business of creating a great city and the assembled team pulled through to deliver value in the best way." The MRVA is located within a sensitive area of the riverbank and could not significantly load the slope. "Deep cuts into the slope could undermine its stability so a foundation system was selected to minimize earthwork," says Brown. "Normally, concrete piles would be used for a foundation for the funicular and stairs, instead, the project was designed to incorporate groups of smaller piles coupled with large piles at the top of the slope that improve overall slope stability." In total, 212 screw piles and 52 diagonal large-diameter concrete piles were used to keep the funicular and stairs from sliding down the hill. "Because the project is situated so close to the city's busiest conference centre as well as the Fairmont Hotel Macdonald, we avoided the use of driven piles to minimize noise," notes Sam Johnson, project manager from Graham, the construction managers on the project. "We also situated the major structural bridge supports in areas where they could be constructed while still maintaining access to pedestrians and vehicles in adjacent areas." The bridge's superstructure is composed of two steel girders and partial depth precast panels. The deck was cast in a fabrication plant, allowing it be installed on site despite cold temperatures and reducing the overall construction schedule. "The entire deck went up in two days over a long weekend in the fall of 2016," says Johnson. One of the primary goals of the project was to improve access in the area for the public, meaning access for the construction crews was challenging. "We needed to put a major effort into planning the sequence of our construction activities to make the most of the little access we had before losing it to the structure we were creating; that required creativity in both the design and construction phases," notes Johnson. "I liken it to spending two years carefully painting yourself out of a corner." The result is what the City of Edmonton refers to as a legacy infrastructure. "We are always looking to build things that help citizens have a better life in Edmonton and are proud of bringing these ideas to reality," says Banford. "We are quite pleased with the final outcome." The MRVA project is one of six projects the City is undertaking with the River Valley Alliance in an effort to increase use and connectivity within the river valley. It is expected to open to the public this fall. 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