What Is the Terzaghi Shallow Foundation Bearing Capacity Calculator?
Terzaghi bearing capacity equation determines the maximum load per unit area a foundation can support without shear failure.
How Does the Terzaghi Shallow Foundation Bearing Capacity Calculator Work?
Combines Prandtl plastic equilibrium with wedge failure geometry to solve for factors Nc, Nq, and Ngamma.
Terzaghi Shallow Foundation Bearing Capacity Calculator Formula & Variables
The core mathematical equation utilized by this calculator is expressed as:
q_{ ext{ult}} = c N_c + q_0 N_q + rac{1}{2} gamma B N_gamma, quad q_{ ext{all}} = rac{q_{ ext{ult}}}{ ext{FS}}
Terzaghi general bearing capacity equation with Vesic bearing factors.
How to Use the Terzaghi Shallow Foundation Bearing Capacity Calculator
- Input soil cohesion c, surcharge q0, soil unit weight gamma, footing width B, and friction angle phi.
Step-by-Step Example Calculation
Continuous Strip Footing in Silty Sand
Input Values:
cohesionKPa:15
surchargeQ0KPa:25
soilUnitWeightKnM3:18.5
footingWidthBMeters:1.8
frictionAngleDeg:28
Worked Steps: Ultimate capacity q_ult = 952.1 kPa; allowable bearing capacity q_all = 317.4 kPa (with FS = 3.0).
Understanding Your Result
Provides ultimate capacity and design allowable bearing capacity with a typical Factor of Safety of 3.0.
Factors That Affect the Result
- High groundwater table near the base reduces effective soil unit weight by ~50%, reducing Ngamma contribution.
When Should You Use This Calculator?
- Designing building spread footings, strip footings, and geotechnical bearing verification.
Assumptions & Limitations
- Assumes general shear failure in dense/stiff soil; loose soils require local shear reduction.
Frequently Asked Questions
Calculation Accuracy & Reference Note
Standard geotechnical shallow foundation engineering model.