Performance Based Excavation Support Design for Challenging Urban Site Geometry in Toronto, Canada-Video

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Video Summary

Erica Acton of Isherwood Geostructural Engineers presents the excavation support design for Toronto’s future EQ Bank Tower, built above a retained 1941 heritage façade. The 18-metre excavation was constrained by neighboring buildings, dense underground infrastructure, and a gas main discovered much closer to the façade than records indicated. To preserve clearance and allow utility access, the team used hydrovac-installed spile shoring, followed by micropile columns and shoring, anchors, and king piles supporting the façade. Along the east wall, anchored shotcrete shoring and extensive instrumentation addressed a sensitive neighboring apartment building and the movement risks of highly stressed Georgian Bay shale.<br /><br />Construction challenges included a damaged micropile and spiles that could not reach target depths because of obstructions; both were managed through monitoring and adjusted excavation methods. Overall movements remained within expected limits, and the project performed successfully. Acton emphasizes clear, repeated communication, reliable monitoring, and timely utility information as essential to complex urban excavation projects.

Keywords

excavation support design

EQ Bank Tower

heritage façade preservation

micropile shoring

urban excavation monitoring

Georgian Bay shale