Thinking Bigger – 32-Storey Building on Helical Piles-Paper

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The paper presents a 32-storey residential tower in downtown London, Ontario, demonstrating that helical piles can support large, heavily loaded structures—not just lightweight foundations.<br /><br />The constrained urban site had nearby buildings, a high water table, limited equipment access, traffic disruption concerns, and compressible soil. Conventional driven piles were considered unsuitable because of noise, vibration, and equipment requirements. Caissons would have required deep drilling, casing, and costly removal of wet soil. Preliminary estimates indicated that helical piles could meet the building’s needs while reducing foundation costs by approximately 60%, with fewer logistical impacts and no excavated spoils.<br /><br />Before design, the team installed and load-tested three compression piles and one tension pile. The tests showed strong performance, and results supported design resistances of 340 kips (1,510 kN) in compression and 174 kips (770 kN) in tension. The testing also helped establish a repeatable installation method, including penetration into dense sand and gravel and grout placement around the pile shafts.<br /><br />The final foundation comprised 543 piles: 467 for compression loads and 76 for combined compression and tension. Installation took 42 working days, averaging 13 piles per day, with the piles advanced to the required torque or refusal in dense soil.<br /><br />The project shows how pre-design testing and early evaluation can make helical piles a viable, efficient deep-foundation option for major buildings. Along with substantial cost savings, the approach reduced noise, vibration, soil handling, and disruption, and allowed subsequent construction to proceed without delay.

Keywords

helical piles

residential tower

deep foundation

load testing

compression piles

tension piles

urban construction

cost savings

London Ontario

foundation design