H & W Produce Building Addition

This project is located at 90 McKenny Avenue, St. Albert, Alberta. Following the issuance of geotechnical report, it was determined that helical pile would provide the most effective and economical foundation solution for the site.

An efficient helical pile design was developed based on the subsurface ground conditions encountered. Given that the subsurface soil conditions consisted of uniform firm silt without encountering any stiff to hard cohesive soil or compact to very dense cohesionless soil, the helical pile was designed with two helices, spaced near critical spacing to helix diameter ratio of 3, which would behave as cylindrical shearing mode. This way the failure zone is expanded and the capacity of the pile is maximized.

After designing the helical pile, the installation torque of the pile was estimated based on the re-moulded shear strength of the soil mobilized around the perimeter of the pile.

After determining the pile load and the stress mobilized on the helices, the pile shaft thickness, helices shaft and weld thickness were determined using appropriate structural analysis and failure modes.

Finally, a stamped shop drawing was issued that included detailed design of helical pile and general notes. The general notes included code of references, reference to geotechnical site investigation report (frost depth, and soil parameters), reference to structural drawings (pile capacity, pile cut-off, and etc), and inspection of work.