1. SUBJECT NAME: FOUNDATION ENGINEERING SUBJECT CODE: CE 1306By
R.Navaneethan
Lecturer
Department of Civil Engineering
PITS

2. FOUNDATION ENGINEERING
OBJECTIVE
This subject is introduced to students with well organized five units, to let know the basics of soil mechanics through studying the properties and testing methods available for soil in context with Civil Engineering

3. TOPICS SITE INVESTIGATION AND SELECTION OF FOUNDATION
SHALLOW FOUNDATION
FOOTINGS AND RAFTS
PILES
RETAINING WALLS

4. Foundation Engineering
In a broad sense, foundation engineering is a art of selecting, designing and constructing the elements that transfer the weight of structure to the underlying soil or rock.
The role of engineer is to select the type of foundation, its design and supervision of construction.
Before the engineer can design a foundation intelligently, he must have a reasonably accurate conception of the physical properties and the arrangement of the underlying materials. This requires detailed soil explorations.

5. Unit I SITE INVESTIGATION AND SELECTION OF FOUNDATION
Methods of exploration
Sampling
Penetration tests
Selection of foundation based on soil condition.

6. Standard Penetration Test
Useful in determining properties of cohesionless soil
Simple and inexpensive
Use a split-spoon sampler

7. Core Boring

8. Unit II SHALLOW FOUNDATION
Bearing capacity of shallow foundation on homogeneous deposits
Factors affecting bearing capacity
Methods of minimizing settlement
SPT, SCPT and plate load

9. Bearing Capacity : Modes of Failure
Strip footing in
dense soil
Load q (kN/m2)
Settlement (mm)
Sudden appearance of a clearly defined distinct failure shape
General shear Failure

10. Unit III FOOTINGS AND RAFTS
Types of foundation
Isolated and combined footings
Mat foundation
Floating foundation

11. Combined Footing
Whenever two or more columns in a straight line are carried on a single spread footing, it is called a combined footing.
Isolated footings for each column are generally the economical.
Combined footings are provided only when it is absolutely necessary, as
Where soil bearing capacity is low, causing overlap of adjacent isolated footings,
Proximity of building line or existing building or sewer, adjacent to a building column,
When two columns are close together, causing overlap of adjacent isolated footings.

12. TYPES OF COMBINED FOOTINGS

13. Factors influencing the selection of pile
Unit IV PILES
Factors influencing the selection of pile
Interpretation of pile load test
Forces on pile caps
Capacity under compression and uplift

14. Pile Load Test
Load imparted to pile in gradual steps to twice design load, as settlement data recorded
Often, load removed in steps, too, to produce load-deflection curve
Behavior
Elastic deformation
Buckling
Puncture
Ensure multiple deflection references, in case one is lost

15. Pile Load Test

16. Active and passive states Condition for critical failure plane
Unit V RETAINING WALLS
Active and passive states
Condition for critical failure plane
Coloumb’s wedge theory
Pressure on the wall due to line load

17. DESIGN The designed retaining wall must be able to
ensure the following :
Overturning doesn’t occur
Sliding doesn’t occur
The soil on which the wall rests mustn’t be overloaded
The material used in construction are not overstressed.

19. TEXT BOOKS
Murthy, V.N.S., “Soil Mechanics and Foundation Engineering”, UBS Publishers Distribution Ltd, 1999
Gopal Ranjan Rao, A.S.R.,”Basic and Applied Soil Mechanics”, Wiley Eastern Ltd., 2003
REFERENCES
Das, B.M., “Principles of Foundation Engineering, 5th Edition, Thomson Books,2003
Kaniraj, S.R., “Design Aids in Soil Mechanics and Foundation Engineering”, Tata McGraw Hill Publishing Company Ltd., 2002
Bowles, J.E., “Foundation Analysis and Design”, McGraw-Hill, 1994

20. ASSIGNMENT TOPICS Problems in footings Problems in retaining walls
Study of Plastic equilibrium in soils

21. URL en.wikipedia.org/wiki/Foundation_(engineering)
en.wikipedia.org/wiki/Foundation_engineering

22. SYLLABUS UNIT I SITE INVESTIGATION AND SELECTION OF FOUNDATION
Scope and objectives – Methods of exploration-averaging and boring – Water boring and rotatory drilling – Depth of boring – Spacing of bore hole - Sampling – Representative and undisturbed sampling – Sampling techniques – Split spoon sampler, thin tube sampler, stationary piston sampler – Bore log report – Penetration tests (SPT and SCPT) – Data interpretation (Strength parameters and Liquefaction potential) – Selection of foundation based on soil condition.
UNIT II SHALLOW FOUNDATION
Introduction–Location and depth of foundation – Codal provisions – Bearing capacity of
shallow foundation on homogeneous deposits – Terzaghi’s formula and BIS formula –
Factors affecting bearing capacity – Problems-bearing Capacity from insitu tests (SPT,
SCPT and plate load) – Allowable bearing pressure, settlement – Components of
settlement – Determination of settlement of foundations on granular and clay deposits –
Allowable settlements – Codal provision – Methods of minimizing settlement –
Differential settlement.

23. UNIT III FOOTINGS AND RAFTS
Types of foundation – Contact pressure distribution below footings and raft – Isolated and combined footings – Types – Proportioning – Mat foundation – Types – Use –Proportioning – Floating foundation.
UNIT IV PILES
Types of piles and their function – Factors influencing the selection of pile – Carrying
capacity of single pile in granular and cohesive soil – Static formula – Dynamic formulae (Engineering news and Hiley’s) – Capacity from insitu tests (SPT and SCPT) – Negative skin friction – Uplift capacity – Group capacity by different methods (Feld’s rule, Converse Labarra formula and block failure criterion) – Settlement of pile groups –Interpretation of pile load test – Forces on pile caps – Under reamed piles – Capacity
under compression and uplift.
UNIT V RETAINING WALLS
Plastic equilibrium in soils – Active and passive states – Rankine’s theory – Cohesionless and cohesive soil – Coloumb’s wedge theory – Condition for critical failure plane –Earth pressure on retaining walls of simple configurations – Graphical methods (Rebhann and Culmann) – Pressure on the wall due to line load – Stability of retaining walls.