Introduction
Shallow foundations are widely used to support structures where soil bearing capacity is
sufficient at shallow depths. While these foundations are typically designed for vertical loads,
there are cases where inclined loads act on them due to wind, seismic activity, or other lateral
forces. Understanding the effects of inclined loads on shallow foundations is essential to ensure
structural stability and prevent excessive settlement or failure.



Effects of Inclined Loads
When a shallow foundation is subjected to an inclined load, the force can be broken into two
components:
1. Vertical Component – Contributes to the bearing capacity of the soil.
2. Horizontal Component – Induces sliding and overturning moments, which can lead to
instability.
The presence of an inclined load reduces the effective bearing capacity of the foundation
since part of the load acts in the horizontal direction, requiring special considerations in design.
Bearing Capacity Reduction
Terzaghi’s bearing capacity theory is commonly used for shallow foundations under vertical
loading. However, when inclined loads are present, the ultimate bearing capacity (σₓ) is modified
using an inclination factor:




Here, H and V are the horizontal and vertical components of the inclined load. As the inclination
increases, the effective bearing capacity decreases, necessitating larger foundation dimensions or
reinforcement.
Design Considerations

Conclusion
Inclined loads can significantly affect the performance of shallow foundations by reducing
bearing capacity and increasing instability risks. Proper consideration of inclination factors,
sliding resistance, and soil-structure interaction is crucial in design. Engineers must analyze these
factors to ensure safety and optimal performance of shallow foundations under inclined loads.
1. Terzaghi, K. (1943). Theoretical Soil Mechanics. John Wiley & Sons.
2. Bowles, J.E. (1996). Foundation Analysis and Design. McGraw-Hill.
3. Das, B.M. (2010). Principles of Foundation Engineering. Cengage Learning.
4. Coduto, D.P. (2001). Foundation Design: Principles and Practices. Pearson Education.


5. Eurocode 7: Geotechnical Design (EN 1997-1:2004). European Committee for
Standardization (CEN).