The GIUSTI Group of Calgary Alberta formed the foundations, columns and floors for this six story concrete and steel condominium project in Kelowna, BC. All footing pads for the 285 unit project were formed with Fastfoot®.
Over the past 25 years the Giusti Group has built more than 600 custom homes and 35,000 multi-family units.
The photo below shows an overview of the site. On the right side can be seen three pads and columns already poured. The contractor is now setting up the next set of footing pads using Fastfoot®.
The building site was complex for two reasons: first the danger of liquefaction under seismic shaking; and second, settlement under static loads.
"To eliminate the possibility of liquefaction, we used vibral compaction and sand columns", said Randy Hillaby, geotechnical engineer with Levelton. "We preloaded the site to prevent static settlement."
As the site was close to Kelowna Lake, with its high water table, dewatering was required to keep the excavation relatively dry. The large PVC pipe in this photo was used to dewater the sand.
As the remediated soils could only support loads of 2,000 pounds per square foot, large footing pads were required to transfer the loads of the building into the ground.
"Our largest pad measured over 15' square, with a depth of 30 inches", said Brian Tomecek, Structural Engineer with TRL & Associates Ltd. "Typical steel configuration was 25 to 30 mm at 300 mm on center."
The irregular building site made form layout very difficult.
"We decided right from the get-go to use a robotic total station", said Scott Saunders, Project Manager.
"Laying out 270 pads on different angles using strings would have been a nightmare. With the station, one man does the layout - a huge labor saving."
In the photo above, 2x10s were precut to the required pad dimensions, and hinged at each corner for fast installation and stripping. Three 2x4 stakes were driven along each 2x10, and a laser used to locate the screed at the exact height.
The screed board's height is at the pad height, making concrete screeding much easier than with plywood forms. Bracing was installed on each stake to withstand lateral loads. The contractor reinforces each corner with a 2x4 on 45 degrees.
62" Fastfoot® was stapled to the top of the 2x10s 2" on center. Bricks were used to hold the steel off the ground and hold the fabric in position. Hydraulid loads are reduced by approximately 40% when using Fastfoot® due to form pressures in the bottom third of the form being taken by the fabric itself.
25 and 30mm rebar was used throughout the footings, with horizontals spaced 300mm on center. An overhead crane was used to instal the heavy mats.
Concrete was supplied by Burnco, with branches throughout Alberta, Kelowna, Penticton and Burnaby. 32 MPA concrete was supplied for the footings and slabs.
"This project used over 13,000 yards", said Brandon Moffat, sales representative. "Fastfoot® is an excellent form as it ensures proper hydration of our concrete on hot summer days."
The concrete was placed in deeper pads in two lifts. "Any pad deeper than 18" is best poured in two lifts", confirmed Scott.
At the end of the project, space becomes more and more limited. Storage and movement of formwork becomes increasingly difficult.
"One of the real advantages of Fastfoot® is the reduction of forming materials and the ease of moving 2x10s instead of heavy plywood forms", confirmed Scott.