Bearing Capacity Factor Dependent on Unit Weight for Circular Footing Calculator

Bearing Capacity Factor Formula:

\[ N_γ = \frac{q_{fc} - (σ_s \times N_q)}{0.3 \times γ \times d_{section}} \]

Ultimate Bearing Capacity in Soil:

kPa

Effective Surcharge:

kPa

Bearing Capacity Factor (Surcharge):

Unit Weight of Soil:

kN/m³

Diameter of Section:

Bearing Capacity Factor (Nγ):

1. What is Bearing Capacity Factor Dependent on Unit Weight?

Definition: This is a dimensionless factor used in geotechnical engineering to calculate the ultimate bearing capacity of circular footings, accounting for the soil's unit weight.

Purpose: It helps engineers determine the safe load-bearing capacity of circular foundations in different soil conditions.

2. How Does the Calculator Work?

The calculator uses the formula:

\[ N_γ = \frac{q_{fc} - (σ_s \times N_q)}{0.3 \times γ \times d_{section}} \]

Where:

\( N_γ \) — Bearing capacity factor dependent on unit weight
\( q_{fc} \) — Ultimate bearing capacity in soil (kPa)
\( σ_s \) — Effective surcharge (kPa)
\( N_q \) — Bearing capacity factor dependent on surcharge
\( γ \) — Unit weight of soil (kN/m³)
\( d_{section} \) — Diameter of circular footing section (m)

Explanation: The formula calculates the bearing capacity factor by considering the net bearing capacity (after subtracting surcharge effects) relative to the soil's unit weight and footing size.

3. Importance of Bearing Capacity Factor

Details: Accurate calculation ensures safe foundation design, prevents structural failures, and optimizes construction costs.

4. Using the Calculator

Tips: Enter all required parameters. Default values are provided for typical conditions. The bearing capacity factor for surcharge (Nq) has a ±5% tolerance.

5. Frequently Asked Questions (FAQ)

Q1: What is a typical value for Nγ?
A: For cohesionless soils, Nγ typically ranges from 15 to 40 depending on soil type and friction angle.

Q2: Why is the diameter important in the calculation?
A: Larger diameters distribute load over a greater area, affecting the bearing capacity calculation.

Q3: How does unit weight affect the bearing capacity?
A: Heavier soils (higher unit weight) generally provide greater bearing capacity.

Q4: What if my soil has cohesion?
A: This calculator is for cohesionless soils. For cohesive soils, additional factors must be considered.

Q5: How accurate is this calculation?
A: It provides a theoretical estimate. Field tests and soil investigations are recommended for critical projects.