Bearing Capacity Factor Dependent On Cohesion For General Shear Failure Calculator

Formula Used:

\[ N_c = \frac{q_{nu} - \left(\sigma_s \times (N_q - 1) + 0.5 \times B \times \gamma \times N_\gamma\right)}{C} \]

Net Ultimate BC (q_nu):

Pascal

Effective Surcharge (σ_s):

Pascal

Bearing Capacity Factor Dependent on Surcharge (N_q):

Width of Footing (B):

Meter

Unit Weight of Soil (γ):

N/m³

Bearing Capacity Factor Dependent on Unit Weight (N_γ):

Cohesion in Soil (C):

Pascal

Bearing Capacity Factor Dependent on Cohesion (N_c):

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1. What is Bearing Capacity Factor Dependent on Cohesion?

The Bearing Capacity Factor Dependent on Cohesion (N_c) is a dimensionless constant used in geotechnical engineering to calculate the ultimate bearing capacity of soil. It represents the contribution of soil cohesion to the overall bearing capacity of foundations.

2. How Does the Calculator Work?

The calculator uses the formula:

\[ N_c = \frac{q_{nu} - \left(\sigma_s \times (N_q - 1) + 0.5 \times B \times \gamma \times N_\gamma\right)}{C} \]

Where:

\( q_{nu} \) — Net Ultimate Bearing Capacity (Pascal)
\( \sigma_s \) — Effective Surcharge (Pascal)
\( N_q \) — Bearing Capacity Factor Dependent on Surcharge
\( B \) — Width of Footing (Meter)
\( \gamma \) — Unit Weight of Soil (N/m³)
\( N_\gamma \) — Bearing Capacity Factor Dependent on Unit Weight
\( C \) — Cohesion in Soil (Pascal)

Explanation: This formula calculates the bearing capacity factor that depends on soil cohesion by subtracting the contributions from surcharge and unit weight from the net ultimate bearing capacity, then dividing by the cohesion value.

3. Importance of N_c Calculation

Details: Accurate calculation of N_c is crucial for foundation design as it helps determine the soil's ability to support structural loads. It is particularly important for cohesive soils where cohesion significantly contributes to bearing capacity.

4. Using the Calculator

Tips: Enter all values in the specified units. Ensure all inputs are positive values. The calculator provides the N_c factor which is essential for foundation design calculations.

5. Frequently Asked Questions (FAQ)

Q1: What is the typical range of N_c values?
A: For general shear failure, N_c typically ranges from 5.14 to 37.2, depending on soil conditions and foundation geometry.

Q2: How does N_c differ for different soil types?
A: N_c is higher for cohesive soils (clays) and lower for cohesionless soils (sands). The value is most significant for purely cohesive soils.

Q3: When is this calculation most applicable?
A: This calculation is most applicable for general shear failure conditions in cohesive soils where the foundation width is significant compared to depth.

Q4: What are the limitations of this formula?
A: The formula assumes homogeneous soil conditions, strip footing, and general shear failure mode. It may need modification for local shear failure or special soil conditions.

Q5: How does foundation shape affect N_c?
A: Shape factors are often applied to N_c for rectangular or circular footings. The basic N_c value is typically for strip footings.