CSLB General Building (B)Planning and EstimatingHard
A contractor is reviewing plans for a hillside residential project. The geotechnical report specifies that all foundations must be designed for a 'minimum allowable bearing pressure' of 2,000 pounds per square foot (psf). What does 'allowable bearing pressure' refer to?
- AThe minimum pressure required to compact the soil effectively.
- BThe maximum load the foundation can withstand before it cracks.
- CThe maximum pressure the soil can safely support without excessive settlement or shear failure.
- DThe pressure exerted by the building's dead load on the soil.
Show answer & explanationAnswer & explanation
Correct answer: C. The maximum pressure the soil can safely support without excessive settlement or shear failure.
Allowable bearing pressure is the maximum pressure that a soil or rock foundation can safely carry without undergoing excessive settlement or experiencing shear failure. It's a critical parameter from the geotechnical report for structural engineers to design foundations.
Why the other options are wrong
- A. This describes compaction effort, which is different from the soil's long-term load-bearing capacity.
- B. This describes a failure limit for the foundation material itself, not the soil's capacity.
- D. This is a component of the load applied by the building, not the soil's capacity.
Allowable Bearing Pressure
The maximum average contact stress that a foundation transmits to the soil or rock, which is deemed safe against excessive settlement or shear failure of the supporting ground.
- Determined by geotechnical engineers.
- Crucial for foundation design (footing size, depth).
- Ensures long-term stability and prevents structural damage.
Memory trick: Bearing Pressure: How much earth can bear.