Bearing Capacity Factor Dependent on Surcharge given Dimension of Footing Calculator

Bearing Capacity Factor Formula:

\[ N_q = \frac{q_f - \left(\frac{2}{3} \times C_s \times N_c + 0.5 \times \gamma \times B \times N_\gamma\right)}{\gamma \times D} \]

Ultimate Bearing Capacity (qf):

Cohesion of Soil (Cs):

Bearing Capacity Factor (Nc):

Unit Weight of Soil (γ):

N/m³

Width of Footing (B):

Bearing Capacity Factor (Nγ):

Depth of Footing (D):

Bearing Capacity Factor (Nq):

1. What is Bearing Capacity Factor Dependent on Surcharge?

Definition: This calculator determines the bearing capacity factor (Nq) that depends on surcharge, which is crucial in foundation design to estimate the ultimate bearing capacity of soil.

Purpose: It helps geotechnical engineers and foundation designers calculate the appropriate factor for soil bearing capacity calculations.

2. How Does the Calculator Work?

The calculator uses the formula:

\[ N_q = \frac{q_f - \left(\frac{2}{3} \times C_s \times N_c + 0.5 \times \gamma \times B \times N_\gamma\right)}{\gamma \times D} \]

Where:

\( N_q \) — Bearing capacity factor dependent on surcharge
\( q_f \) — Ultimate bearing capacity (Pa)
\( C_s \) — Cohesion of soil (Pa)
\( N_c \) — Bearing capacity factor dependent on cohesion (±5%)
\( \gamma \) — Unit weight of soil (N/m³)
\( B \) — Width of footing (m)
\( N_\gamma \) — Bearing capacity factor dependent on unit weight (±5%)
\( D \) — Depth of footing (m)

Explanation: The formula calculates Nq by considering all components of bearing capacity and isolating the surcharge-dependent factor.

3. Importance of Bearing Capacity Factor

Details: Accurate calculation of Nq ensures proper foundation design, preventing settlement issues and structural failures.

4. Using the Calculator

Tips: Enter all required parameters. Note that bearing capacity factors (Nc and Nγ) have ±5% uncertainty. All values must be positive.

5. Frequently Asked Questions (FAQ)

Q1: Why is there a ±5% uncertainty for Nc and Nγ?
A: These factors are empirically determined and can vary slightly based on soil conditions and testing methods.

Q2: What units should I use for input values?
A: Use Pascals (Pa) for pressure values, Newtons per cubic meter (N/m³) for unit weight, and meters (m) for dimensions.

Q3: Can I use this for shallow foundations?
A: Yes, this is particularly relevant for shallow foundation design.

Q4: What if my soil has no cohesion (Cs = 0)?
A: Simply enter 0 for Cs in that case.

Q5: How accurate is the calculated Nq value?
A: The accuracy depends on your input values. The result will inherit the ±5% uncertainty from Nc and Nγ.