Foundation Engineering / module 5
Shape, depth and inclination
The corrections that turn a strip-footing equation into a real foundation.
What you will understand
- Explain why a square footing carries more pressure than a strip of the same width
- Apply shape and depth factors, and say when each is worth claiming
- Explain why an inclined load is more damaging than its vertical component alone
- Recognise which corrections are conservative to ignore and which are not
Lessons
Shape and depth
How plan shape and embedment affect each resistance term.
Inclined loads
Why a small horizontal component costs so much.
Module summary
- The base equation is for a strip footing; everything else needs correcting
- Shape factors raise the cohesion and surcharge terms and reduce the self-weight term
- Depth factors credit the shear strength of the ground beside the footing, and grow with D/B
- Shape factors can increase or decrease the total resistance; omission of inclination factors can overestimate it.
- An inclined load reduces capacity far more than its vertical component suggests
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
An uncorrected capacity of 1056 kPa becomes 1290 kPa once shape and depth factors are applied. What is the percentage gain, to the nearest whole number?
Check yourself
For a rectangular footing 2 m by 5 m, what is B in the bearing capacity equation?