Bearing capacity
Bearing capacity is the maximum pressure soil can carry before it fails or over-settles. It sets footing size, and comes from the geotech soil report (in kPa).
Ask Chalkline about this →Bearing capacity is the maximum pressure the ground can carry before it fails or settles too much. It governs footing size: the heavier the load and the weaker the soil, the larger the footing area needed to spread that load down to a pressure the soil can take. It is expressed in kilopascals (kPa).
Two values to know:
- Ultimate bearing capacity: the pressure at which the soil actually fails (shears).
- Allowable bearing pressure: the ultimate value divided by a safety factor, the working figure the engineer designs to.
Where it comes from: the geotechnical engineer estimates bearing capacity from the soil type, its strength, and the bearing strata identified in the soil report.
How it’s used: a footing is sized so that load divided by footing area stays below the allowable bearing pressure. A pad footing under a point load, or a strip footing under a wall, is sized this way. On reactive-clay sites the AS 2870 system drives the slab and footing design; bearing capacity matters most for piers, pads, and footings founded on a specific stratum.
Common issue: founding a footing on fill or soft soil with low bearing capacity, so it settles. Confirm the founding stratum and its bearing value from the soil report before pouring.
Also known as: soil bearing capacity; allowable bearing pressure (the design value).
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Last updated: 2026-05-24. Verified: 2026-05-24. Quarterly review for currency.