Bearing Capacity of Non Cohesive Soil for Circular Footing Calculator

Ultimate Bearing Capacity Formula:

\[ q_{fc} = (\sigma_s \times N_q) + (0.3 \times \gamma \times d_{section} \times N_\gamma) \]

Effective Surcharge (σ_s):

kPa

Bearing Capacity Factor (N_q):

Unit Weight of Soil (γ):

kN/m³

Diameter of Section:

Bearing Capacity Factor (N_γ):

Ultimate Bearing Capacity (q_fc):

1. What is Bearing Capacity of Non Cohesive Soil for Circular Footing?

Definition: This calculator determines the ultimate bearing capacity of non-cohesive soil for circular footings using Terzaghi's bearing capacity equation.

Purpose: It helps geotechnical engineers and foundation designers assess the load-bearing capacity of sandy or granular soils for circular foundation design.

2. How Does the Calculator Work?

The calculator uses the formula:

\[ q_{fc} = (\sigma_s \times N_q) + (0.3 \times \gamma \times d_{section} \times N_\gamma) \]

Where:

\( q_{fc} \) — Ultimate bearing capacity (kPa)
\( \sigma_s \) — Effective surcharge (kPa)
\( N_q \) — Bearing capacity factor for surcharge
\( \gamma \) — Unit weight of soil (kN/m³)
\( d_{section} \) — Diameter of circular footing (m)
\( N_\gamma \) — Bearing capacity factor for unit weight

Explanation: The formula combines the effects of surcharge pressure and soil self-weight to determine the maximum pressure the soil can withstand.

3. Importance of Bearing Capacity Calculation

Details: Proper bearing capacity estimation ensures foundation stability, prevents excessive settlement, and maintains structural integrity.

4. Using the Calculator

Tips: Enter all required parameters with appropriate units. The ±5% indicates typical variability in these parameters for non-cohesive soils.

5. Frequently Asked Questions (FAQ)

Q1: What is effective surcharge?
A: It's the vertical pressure at the foundation level from overburden soil or other surface loads.

Q2: How are N_q and N_γ determined?
A: These factors depend on soil friction angle and are typically obtained from bearing capacity tables.

Q3: Why is the formula different for circular footings?
A: The 0.3 coefficient accounts for the shape factor of circular foundations compared to strip footings.

Q4: What safety factors should be applied?
A: Typical factors of safety range from 2.5 to 3.5 for non-cohesive soils.

Q5: Does this apply to all non-cohesive soils?
A: Yes, for sandy or granular soils with negligible cohesion (c ≈ 0).