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Shallow Foundations
Settlement
G. R. Dodagoudar
DEPARTMENT OF CIVIL ENGINEERING
I I T MADRAS, CHENNAI - 600 036.
See!
Understand!
Understand!
Introduction
A comparison !
Results from elastic theory indicate that the increase
in vertical stress in the soil below the centre of a strip
footing of width B is approximately 20% of the
foundation pressure at a depth of 3B.
In the case of a square footing the corresponding
depth is 1.5B.
For practical purposes these depths can normally be
accepted as the limits of the zones of influence of the
respective foundations and are called the significant
depths.
An alternative approach is to take the significant
depth as that at which the vertical stress is 20% of the
effective overburden pressure. It is essential that the
soil conditions are known within the significant depth
of any foundation.
It is practically impossible to prevent settlement of
shallow foundations.
At least, elastic settlement will occur.
Your task as a geotechnical engineer is to prevent
the foundation system from reaching a
serviceability limit state.
Total Settlement
Some Facts !
Immediate Settlement
Immediate Settlement
Solution:
Example 2
Example 3
Example 4
Example 5
Set-up for plate load test
Set-up for plate load test
Procedure
For square footings in granular soils
Problems