Pile foundation design in Quebec City operates within a regulatory framework shaped by the National Building Code of Canada (NBCC) and CSA A23.3, but the real challenge lies underground. The city rests on a complex stratigraphy of post-glacial Champlain Sea clays, interspersed with glacial till and bedrock at variable depths. This is not uniform terrain — what works near the Plains of Abraham may be entirely inadequate in the Saint-Roch lowlands, where sensitive clays can lose strength dramatically when disturbed. Our technical approach begins with a detailed geotechnical campaign, combining in-situ permeability tests to characterize the silty clay lenses that govern drainage around pile shafts, and then cross-referencing those results with advanced laboratory analysis. Without this integration, even a code-compliant design can fail to anticipate the long-term settlement behavior of these compressible marine deposits.
In Quebec City, the depth to competent bedrock can vary by over 10 meters within a single site — pile design here is never a copy-paste exercise.
