Bearing capacity is the ability of soil or rock to support foundation loads without unacceptable failure or movement under defined conditions.
Definition
Bearing capacity describes how much load soil or rock can support beneath a foundation, based on a defined site, foundation type, and set of assumptions. A geotechnical evaluation may consider subsurface materials, groundwater, foundation dimensions, loading, and construction conditions. Reports may distinguish a limit related to soil failure from a lower design value that includes a safety margin. The design team also considers settlement, because a foundation can experience excessive movement even when bearing failure is not expected. Firms may calculate or report capacity using different methods, units, and assumptions, so the value should be read with its stated basis and limits. It is not a universal property of a soil type, a guarantee that a foundation will perform, or a substitute for project specific investigation and design. ASCE provides resources for civil engineering practice.
How owners use it
- Owners review geotechnical recommendations alongside foundation design assumptions and project scope.
- A project team compares expected foundation loads with the reported allowable bearing pressure, using the report's stated basis.
- For a 100-square-foot footing at 2,000 pounds per square foot, 100 × 2,000 = 200,000 pounds of allowable load under that stated assumption.
- Owners track whether additional investigation or changed foundation assumptions affect fee, schedule, or coordination.
