Net Ultimate Bearing Capacity given Depth and Width of Footing Calculator

Net Ultimate Bearing Capacity Formula:

\[ q_{nf} = (C_s \times N_c) + ((\gamma \times D) \times (N_q - 1)) + (0.5 \times \gamma \times B \times N_\gamma) \]

Cohesion of Soil (Cₛ):

Bearing Capacity Factor (Nₑ):

Unit Weight of Soil (γ):

N/m³

Depth of Footing (D):

Bearing Capacity Factor (N_q):

Width of Footing (B):

Bearing Capacity Factor (N_γ):

Net Ultimate Bearing Capacity (qₙf): Pa

Definition: Net Ultimate Bearing Capacity is the minimum net pressure intensity causing shear failure of soil beneath a foundation.

Purpose: It helps geotechnical engineers determine the safe load that can be applied to a foundation without causing shear failure.

The calculator uses Terzaghi's bearing capacity formula:

\[ q_{nf} = (C_s \times N_c) + ((\gamma \times D) \times (N_q - 1)) + (0.5 \times \gamma \times B \times N_\gamma) \]

Where:

Details: Proper calculation ensures foundation stability, prevents excessive settlement, and maintains structural integrity.

Tips: Enter all required parameters. Default values are provided for common soil conditions. All values must be > 0.

Q1: What are typical values for bearing capacity factors?
A: Nc ≈ 9, Nq ≈ 2.01, Nγ ≈ 1.6 for general cases, but vary with soil friction angle.

Q2: Why is there a ±5% margin?
A: This accounts for variability in soil properties and measurement uncertainties.

Q3: How does footing depth affect bearing capacity?
A: Deeper footings generally have higher bearing capacity due to overburden pressure.

Q4: What units should I use?
A: Use consistent SI units: Pascals for cohesion and bearing capacity, meters for dimensions.

Q5: How conservative is this calculation?
A: It provides theoretical maximum capacity. Apply appropriate safety factors for design.