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NAIT Parkade

NAIT Parkade
Date: 2011

The Northern Institute of Alberta’s five-storey parkade with two levels of underground parking was built to accommodate long-term needs at the growing Edmonton downtown campus facility with 985 additional parking stalls above grade. General contractor Clark Builders awarded AGRA Foundations Limited the installation of 160 belled, cast-in-place piles for the foundation of the parkade. Asphalt and gravel fill over lacustrine, silty clay from about 5.8 to 7 m was overlaying clay till containing sand and silt layers into depths of 34.5 m below ground surface.

Solution:

The AGRA team installed end-bearing cast-in-place belled piles with pile diameters of 400 mm to 1800 mm and bell diameters of 1067 mm to 1829 mm into a minimum depth of 16 m. The bells were generally installed at depths suggested in the geotechnical report, but occasionally extended deeper to ensure they were founded in stiff clay. The piles were designed to provide an ultimate bearing resistance of 1125 kPa. Two track-mounted Soilmec drill rigs provided the capacity and flexibility to install varied pile sizes in an efficient manner.