Terzaghi’s Bearing Capacity Calculator


Ultimate Bearing Capacity (qu):


The Terzaghi Bearing Equation is a cornerstone in geotechnical engineering, providing critical insights into soil behavior under structural loads. Named after Karl von Terzaghi, the father of soil mechanics, this equation is essential in assessing the bearing capacity of soils for foundation design. Understanding this equation is crucial for engineers to ensure the stability and safety of structures.

Understanding the Basics

To grasp the Terzaghi Bearing Equation, one must first understand the concepts of soil mechanics and bearing capacity. Bearing capacity refers to the maximum load a soil can sustain before failure occurs. The Terzaghi Bearing Equation integrates factors such as soil cohesion, soil weight, foundation width, and the depth of the foundation to calculate this capacity. It is a formula that helps predict how soils will behave under different loading conditions.

Terzaghi Bearing Equation

\( q_u = c’N_c + \sigma’_{zD}N_q + 0.5 \gamma B N_{\gamma} \)


  • c’ – Effective soil cohesion,
  • σ’zD – Effective overburden pressure,
  • γ – Unit weight of the soil,
  • B – Width of the foundation,
  • Nc, Nq, Nγ – Dimensionless bearing capacity factors.

Terzaghi’s Bearing Equation is a foundational principle in geotechnical engineering, used to determine the bearing capacity of soils. It plays a vital role in the design of foundations, assessing ground stability, and ensuring structural safety.

Real World Applications

In practical scenarios, the Terzaghi Bearing Equation is extensively used in the design and analysis of foundations. Whether for residential buildings, bridges, or large infrastructures, this equation helps in deciding the type and depth of foundations required. It’s a tool that guides engineers in evaluating ground stability, selecting suitable construction materials, and ensuring the longevity and safety of structures.

Limitations and Considerations

While the Terzaghi Bearing Equation is fundamental in geotechnical engineering, it does have limitations. The equation assumes homogenous soil conditions, which is rarely the case in natural settings. It also does not account for factors like soil layering, water table fluctuations, and long-term soil behavior. Engineers must consider these limitations and often combine the Terzaghi equation with other methods and empirical data for a comprehensive understanding of soil behavior.