Bearing capacity definitions: The maximum net pressure intensity that causes shear failure of the foundation soil is termed as which capacity?
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ASafe bearing capacity
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BNet safe bearing capacity
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CNet ultimate bearing capacity
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DUltimate bearing capacity
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EAllowable bearing pressure
Answer
Correct Answer: Net ultimate bearing capacity
Explanation
Introduction / Context:Foundation design differentiates between ultimate capacities (at failure) and safe/allowable pressures (factored down for service). Net versus gross also matters: net subtracts the overburden at foundation level, while gross includes it. The question asks specifically about the maximum net pressure that causes shear failure.
Given Data / Assumptions:
- Failure is defined by shear failure in the supporting soil.
- Net pressure = applied contact pressure minus overburden at foundation level.
- No settlement criteria are implied in the term “ultimate”.
Concept / Approach:
Definitions: Gross ultimate q_u (gross) causes failure. Net ultimate q_nu = q_u − γ D_f removes the contribution of the soil overburden. Safe or allowable pressures are obtained by applying a factor of safety or by satisfying serviceability (settlement) limits.
Step-by-Step Solution:
Identify keyword “maximum net pressure causing shear failure”.Map to term → net ultimate bearing capacity (q_nu).Distinguish from safe/allowable which are reduced from ultimate.Verification / Alternative check:
Design manuals define q_nu explicitly as the net pressure at failure, confirming option (c).
Why Other Options Are Wrong:
(a) and (b) are service values; (d) is ultimate but gross, not net; (e) is a design pressure, not a failure capacity.
Common Pitfalls:
Confusing gross and net; using allowable pressure without checking settlement criteria.
Final Answer:
Net ultimate bearing capacity