Seismic & Liquefaction Assessments
Earthquakes don’t just shake buildings, they can liquefy the ground below us and change how it behaves. In the Lower Mainland, Sea-to-Sky, and many riverfront areas of B.C., loose sands, silts, fills, and soft clays can amplify or dampen shaking, lose strength (liquefy), and deform laterally. This is where our in-house West Coast CPT team is a major advantage: CPT/SCPT gives us continuous strength and stratigraphy with shear-wave velocity (Vs) testing for site class and stiffness so we can quantify risk quickly and turn it into buildable, permit-ready designs.
We tailor the scope to your ground. On granular, weak soils such as the majority of Delta and Richmond and communities along the Fraser River, we lead with CPT (tip, sleeve, pore pressure) and SCPT (Vs for stiffness and Vs30 analysis), then drill to gain soil samples to calibrate testing instruments and ground models with lab testing of soil samples. Our in-house soils lab provides fast-turn index testing (moisture, Atterberg limits, gradation/hydrometer, unit weight, organic content) and compaction; specialty cyclic or consolidation testing is coordinated with advanced labs. The result is a reconciled soil/groundwater model that reflects your actual site, not generic, over conservative assumptions.
We establish seismic site class from SCPT/MASW and, when warranted, run site-specific response to produce spectra the structural engineer can use directly (Site response analysis). For liquefaction and cyclic softening we evaluate triggering, post-event strengths, settlements, and lateral deformation (including lateral spread potential near waterways and slopes). For sloped ground or excavations, we check seismic stability and expected displacements. Methods are current and reviewer-friendly (CPT, SPT, and lab-based frameworks), and we document inputs/assumptions clearly so the path from data to design is easy to follow.
We convert results into decisions you can build. If shallow foundations are viable, we set bearing levels/design subgrade elevations, settlements, and bearing capacities to avoid seismic punching failure or settlement. Where improvement is required to prevent foundation punching, we design ground improvement solutions matched to your soils and schedule, including:
If deep foundations are appropriate, we size driven or drilled piles including precast, steel, cast-in-place, timber, helical, or micropiles, for axial/lateral demands, including downdrag and kinematic effects through liquefying layers, soft sensitive clays, and decaying organics (peat and organic silt/clay) which pose major movement and settlement risks to the project.
Good seismic design doesn’t end on paper. We define practical verification plans for pre and post densification. This can include CPT grids (our West Coast CPT team can mobilize quickly), targeted SPTs/DCPTs, so effectiveness can be confirmed in the field. During construction we execute the verification plan through field review and, where risk warrants, instrumentation (settlement plates/survey points, piezometers, vibration monitoring) with threshold-based reporting to keep work on track and documented.
We provide pre- and post-construction surveys for pile installation, blasting, excavation, and drilling near existing structures. These surveys document baseline conditions and help determine whether construction activities have caused any impacts.
We are equipped with vibration monitoring instrumentation for piling, blasting, densification, excavation, and drilling projects. Our systems provide continuous monitoring of structural and ground vibrations to verify that construction activities remain within acceptable limits.
Owning our CPT/SCPT equipment means the same engineers who design and write the report also monitor testing results in real time, ensuring accurate data collection and design-ready interpretation. This approach allows faster mobilization, continuous soil profiling (critical in variable deltaic deposits), and direct Vs30 measurements for seismic site class and response analysis. By integrating high quality field testing results directly into design, we reduce uncertainty and avoid unnecessary conservatism on soft soil or liquefiable sites.
