1. Design of Reinforced Concrete Foundations
Lecture (7)
Design of Reinforced Concrete Foundations
DR: Ahmed Afifi
Ass. Teacher: Ahmed Said

2. INTRODUCTION TO FOUNDATIONS
Function of a foundation is to transfer the structural loads from a building safely into the ground.
Purpose of foundation:-
To distribute the weight of the structural over large area so as to bring down the intensity of load at its base below the safe bearing capacity of sub-soil.
To support the structures.
To distribute the non-uniform load of the superstructure, uniform to the sub-soil.

3. The foundation can be broadly classified into:
Shallow foundations
Deep foundations

4. Types of Shallow Foundations:
Placed immediately below the lowest part of the superstructure. Its purpose is to distribute the load over a wide area.
Shallow foundations are usually embedded about a meter or so into soil
Types of Shallow Foundations:
Spread footing ( Rectangular, Square and Circular footing )
Combined footing
Strap or Cantilever footing
Strip footing
Mat or Raft footing

5. 1-Spread footings 2-Combined footings
Such as rectangular and square footings are economical for support
Column under normal condition
2-Combined footings
Is a system of foundation that support more than one columns (usually 2 columns)

6. 3-Strap footings 4-Strip footings
When two columns are far apart, a strap is designed to transfer eccentric moment between two columns
4-Strip footings
Strip foundations consist of a continuous strip, usually
of concrete, formed centrally under load bearing.
walls

7. 5-Raft footings
Raft foundation is a thick concrete slab reinforced with steel which covers the entire contact area of the structure like a thick floor. Sometimes area covered by raft may be greater than the contact area depending on the bearing capacity of the soil underneath. The reinforcing bars runs normal to each other in both top and bottom layers of steel reinforcement.