We were called to a site near Still Creek a few years back — a four-story condo project where the geotechnical report had flagged ‘potential liquefaction’ but didn’t run the numbers. The developer figured it was a minor check. After our soil liquefaction analysis in Burnaby, we found loose sands down to 12 meters that would likely settle under a design earthquake. That pushed the foundation design from shallow footings to deep piles. In Burnaby, the combination of glacial till overlain by recent alluvial deposits along the Fraser River floodplain creates a tricky profile: dense layers cap loose, saturated sands. Without a proper CPT test to map those transitions, you’re flying blind. We use NCEER (Youd-Idriss 2001) methodology paired with local borehole data to calculate factor of safety against liquefaction for each stratum.
In Burnaby, loose sands under the water table can liquefy in a magnitude 6.8 event — we test every layer, not just the surface.
Service characteristics in Burnaby
- SPT N-values corrected for energy and overburden (CSA A23.2-9A / CSA A23.2-9A / CSA A23.2-9A / CSA A23.2-9A / CSA A23.2-9A / ASTM D1586)
- Fine content adjustment per the NCEER workshop procedures
- Cyclic resistance ratio (CRR) versus cyclic stress ratio (CSR) for each 1.5 m interval
Typical technical challenges in Burnaby
Burnaby’s urban growth really took off in the 1990s, with high-rises filling the Brentwood and Lougheed corridors. But the city sits on a mix of glacial deposits and post-glacial sediments, including soft alluvial clays and loose sands along the Deer Lake and Burnaby Lake basins. A soil liquefaction analysis in Burnaby is not optional for any building taller than three stories or any structure near a watercourse. The NBCC 2020 seismic hazard map puts Burnaby at moderate-to-high hazard (Sa(0.2) around 0.6 g). We’ve seen sites where the top 6 meters look stiff but the sand below the water table would likely liquefy under a 1-in-475-year event. Ignoring that can lead to differential settlement, foundation rotation, or even collapse during an earthquake.
Our services
We offer four key services related to soil liquefaction analysis in Burnaby, each tailored to the site conditions we encounter most often.
SPT-Based Liquefaction Assessment
Standard penetration tests at 1.5 m intervals with energy correction. We apply the NCEER (Youd-Idriss 2001) curves to compute CRR and factor of safety for each layer.
MASW / Vs30 Profiling
Multichannel analysis of surface waves to measure shear-wave velocity down to 30 m. Used to classify site class per NBCC 2020 and cross-validate SPT-based liquefaction models.
Liquefaction-Induced Settlement Analysis
Post-liquefaction volumetric strain estimates using Tokimatsu & Seed (1987) or Ishihara & Yoshimine (1992) methods. Critical for mat foundations and shallow footings.
Lateral Spread & Flow Slide Evaluation
Assessment of potential lateral displacement on slopes and near embankments using Newmark sliding block analysis and empirical relationships from Bartlett & Youd (1995).
Frequently asked questions
How much does a soil liquefaction analysis cost in Burnaby?
For a typical residential lot or small commercial site in Burnaby, the cost ranges from CA$3,740 to CA$6,320. This includes 2–3 boreholes with SPT, laboratory fines content, and a detailed report with factor of safety per layer. Larger sites or those requiring MASW profiling will be on the higher end.
What soil types in Burnaby are most prone to liquefaction?
Loose to medium-dense silty sands and clean sands below the groundwater table are the main concern. These are common along the Fraser River floodplain (e.g., Big Bend area, Still Creek corridor) and around Burnaby Lake. Glacial till and compacted fills generally have high enough density to resist liquefaction.
Do I need a liquefaction study for a single-family home in Burnaby?
Not usually, unless the home is on a waterfront lot or near a steep slope. The NBCC 2020 exempts buildings of 1 or 2 stories on shallow foundations in low-hazard zones from detailed liquefaction analysis. But if you’re building near Burnaby Lake or the Fraser River, it’s wise to check — we’ve seen cases where the water table is only 2 m deep.