Utilization of Micropiles at the Expansion of BMO Field, Toronto, Canada-Paper

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BMO Field’s 2014–2016 expansion added seating and twin canopies to the Toronto stadium. The west canopy foundations presented major challenges: existing SubAir heating and drainage infrastructure, buried utilities, limited access, and low headroom made conventional deep foundations impractical. Micropiles could be installed from existing indoor spaces without disrupting the SubAir system.<br /><br />The project installed 46 micropiles in three restricted work areas. Designed for factored loads of up to 3,000 kN in tension and 4,000 kN in compression, the piles used permanent casing and bundled threaded-steel bars extending into 4–9 m rock sockets in Georgian Bay shale. Minimum axial stiffness requirements (EA) governed reinforcement selection. Excavation support, steel drilling templates, and specialized equipment enabled safe, accurate installation despite tight clearances and nearby services.<br /><br />The contractor proposed foregoing full-scale load testing based on extensive prior tests of comparable micropiles in the same shale, built using similar methods. The project team accepted the proposal, supported by the contractor’s experience and enhanced Type B pressure grouting. The authors emphasize that this was an exceptional, project-specific decision—not a recommendation to routinely omit load testing.<br /><br />Quality assurance included grout specific-gravity testing, strength testing of grout cubes, detailed construction records, and full-time inspection under a 64-point inspection and testing plan. All piles were installed safely and accepted for their intended use. Early design-build contractor involvement helped coordinate foundation design and excavation support, reduce costs, protect existing infrastructure, and meet the construction schedule.

Keywords

BMO Field

micropiles

Toronto stadium

west canopy

SubAir system

georgian bay shale

foundation challenges

pressure grouting

load testing

construction quality assurance