Designing effective vibrocompaction in London, Ontario demands more than just selecting a grid spacing. The Ontario Building Code (OBC) and CSA A23.3 set clear performance benchmarks for densified ground, particularly when loose sands or uncontrolled fill underlie a site. In London, the post-glacial geology introduces layers of silty sand, outwash deposits, and occasional till lenses that can vary sharply within a single property. A standard design that ignores these transitions often fails to meet specified relative density targets. Our team develops vibrocompaction layouts that account for the real stratigraphy encountered in southwestern Ontario, referencing pre-condition CPT or SPT data to calibrate vibrator energy, probe penetration rates, and backfill gradation. For projects where foundation demands are higher, we integrate the densification plan with footings analysis to verify that shallow bearing pressures remain within allowable limits after treatment.
A vibrocompaction design calibrated to London's glacial sand plains can increase relative density from below 50% to above 75% in a single field season.
Our approach and scope
Site-specific factors
A common mistake we see in London is treating the entire site as a homogeneous sand body and running the vibrator on a single setting from top to bottom. When silty interbeds or clay seams are present—and they frequently are in the transition zones between Port Stanley Till and overlying sand—the vibrator can simply remold the fine layer without densifying it. The result is a treated profile that looks acceptable on average but contains soft horizons that later compress under foundation load. Another costly error is skipping pre-treatment CPT soundings and relying solely on borehole logs, which miss thin loose zones that control settlement. A defensible vibrocompaction design requires baseline cone resistance data at close spacing, clear refusal criteria for the vibrator probe, and a defined procedure for switching to stone column reinforcement if fines content exceeds the vibrocompaction applicability threshold.
Applicable standards
Ontario Building Code (OBC) Part 4 — Structural Design, CSA A23.3 — Design of Concrete Structures (seismic provisions), ASTM D6066 — Standard Practice for Determining the Normalized Penetration Resistance of Sands for Evaluation of Liquefaction Potential, ASTM D5778 — Standard Test Method for Electronic Friction Cone and Piezocone Penetration Testing of Soils
Other technical services
Performance-Based Vibrocompaction Design
We produce a complete design package including grid layout, lift thickness, vibrator specifications, and QC acceptance criteria. The design is calibrated to site-specific CPTu data and targets the relative density required to mitigate static settlement and liquefaction under the design earthquake specified by the National Building Code of Canada.
Construction Support and Field Verification
We provide on-site technical oversight during the trial zone execution, adjust design parameters in real time based on probe penetration rates and ammeter response, and supervise post-treatment CPT testing. Final documentation includes as-built records and a signed statement of compliance with the OBC and CSA standards.
Typical parameters
Quick answers
How much does vibrocompaction design cost for a site in London, Ontario?
Design fees typically range from CA$1,820 to CA$6,280 depending on the treated area, depth of densification, and the number of verification points required. Projects under 500 m² with straightforward sand profiles fall at the lower end. Larger sites requiring multiple trial zones, detailed CPT correlation, and seismic liquefaction analysis move toward the upper range.
What soil types in London are suitable for vibrocompaction?
Vibrocompaction works best in clean to slightly silty sands with fines content below 12 to 15 percent. In London, the stratified sand plains and outwash deposits generally fall within this range, but glacial till layers with higher clay content are not densifiable by vibration alone. We always run a grain-size analysis on samples from the target zone before committing to the method.
How long does the design and QC process take from investigation to sign-off?
A typical timeline spans three to four weeks: one week for pre-treatment CPT field work and data processing, one week for design development, and one to two weeks covering the trial zone execution and post-treatment verification testing. Larger industrial sites with deep treatment depths may extend the schedule by an additional week.