Foundation Engineering / module 6
Eccentric and inclined loading
When the load is not in the middle — and what the footing does about it.
What you will understand
- Apply Meyerhof's effective area method to an eccentrically loaded footing
- Derive and apply the middle-third rule, and say what happens beyond it
- Explain why a moment and a horizontal load are different problems with different remedies
- Recognise the combined V–H–M failure envelope that the factor method approximates
Lessons
The effective area method
Shrink the footing until the load is in the middle.
Combined V, H and M
What the factors are approximating.
Module summary
- An eccentric load is handled by shrinking the footing until the load is central on what remains
- Effective width is B − 2e, so eccentricity costs twice its own value in width
- Beyond e = B/6 the resultant leaves the middle third and contact is lost at one edge
- Eccentricity and inclination are separate effects and both must be applied
- The real behaviour is a V–H–M failure envelope; the factor method is a serviceable approximation to it
Teaching basis and review status
These are educational models and exercises. Check their assumptions before using the results. The full technical content and every diagram have not yet been independently verified.
Concrete and steel calculations retain their stated first-generation Eurocode teaching basis. Use the standards and amendments specified for your project; do not mix generations without an appropriate design basis.
Read the lesson register and outstanding review notesCheck your understanding
Practice
A 3.0 m square pad carries 900 kN with a moment of 360 kNm about one axis. What is the effective area, in m²?
Practice
For a 2.4 m wide footing, what is the largest eccentricity that keeps the resultant within the middle third, in metres?