foundnation it is for all poly diploma student as a part of subject buiding tehnology follow me for all material u need for your notes this chennal is gold for all poly diploma student and can help u a lot . this is single step in doing exel at your college matches exactly to syllabus of poly dipolma and for all enginners good luck i hope this slide gives u all the information u need

1. FOUNDATION

2. CONCEPT OF FOUNDATION
THE BASIC FUNCTION OF FOUNDATION IS TO TRANSMIT THE SUPERIMPOSED LOAD OF
BUILDING TO THE SUPPORTING SOIL .
GL
FOUNDATION

3. Factors affecting the selection of
foundation
1. LOAD FROM THE BUILDING - The foundation shall be constructed to
transmit the load of building to subsoil in such a way that it does not
impair the stability. Load of building depends upon the number of floor
and material used and structure
 FOR BUILDING WITH HEAVY LOAD AND LESS AREA (which is heavy) ,deep
foundation is required.
 FOR LOW RISED BUILDING WITH LARGE AREA (which is light) , shallow
foundation is sufficient .
2. TYPE OF SOIL – (1)if the soil close to surface is capable of supporting
structural load then shallow foundation is preferred.

4. 2) Where ground close to the surface is not capable of supporting structural load , hard
strara is searched for and deep foundation is required.

5. BEARING CAPACITY
DEFINATION – The capacity of soil to support the load applied to the it.

6. ULTIMATE BEARING CAPACITY
The maximum load which soil can take per unit area without
displacement .

7. TYPES OF FOUNDATION
1. SHALLOW FOUNDATION
2. DEEP FOUNDATION

8. SHALLOW FOUNDATION
If the depth is equal or less than its Base and less than 3m , then it is termed
as shallow foundation
D≤B

9. TYPES OF SHALLOW FOUNDATION
1. Spread footing
2. Raft foundation
3. Strap footing
4. Combined footing

10. SPREAD FOOTING
 Spread footing are those which spread the superimposed load of a wall or
column over a large area.
 Spread footing support either a column or wall .
TYPES OF SPREAD FOOTING
1. Single footing for a column
2. Stepped footing for a column
3. Stepped foot
4. Wall footing for wall

11. RAFT FOUNDATION
 It is used to spread the load from a structure over a large area , normally
the entire area of structure.
 they are often needed on the soft/loose soil with low bearing capacity as
they can spread the load over a larger area.

12. RANKINE’S FORMULA FOR DEPTH OF
FOUN.
where, h= minimum depth of foundation
p= gross bearing capacity
Ƴ=density of soil
Ø=angle of repose or internal friction of soil

13. DEEP FOUNDATION
If depth is equal to or greater than the base , it is known as deep foundation.
( DEPTH IS GREATER THAN BASE)
Q)WHY DO WE USE DEEP FOUNDATION ?
ans)
 If the bearing capacity of soil is low
 Non availability of proper bearing stratum at shallow depth
 Heavy load from the superstructure for which shallow foundation may not
be suitable.
TYPES OF DEEP FOUNDATION -
1)Pile foundation

14. PILE FOUNDATION
Pile foundation is that type of foundation in which the load are taken to a
low level by means of vertical member which may be made of timber ,
concrete or steel.
SUITABILTY OF PILE FOUNDATION –
1. When the load of superstructure is heavy and distribution is uneven
2. When top soil has poor bearing capacity and hard stratum of required
capacity is at greater depth
3. The structure is situated near sea shore or river bed ,where there is
danger of scouring action of water.

15. TYPES OF PILE FOUNDATION
According to function
1. End bearing piles
2. Friction piles
3. Compaction pile
4. Tension pile
5. Anchor pile
6. Fender pile
7. Batter pile
8. Sheet pile

16. End bearing pile – End bearing piles are used to transfer load through water
or soft soil to a suitable bearing stratum
1. They are driven into ground until hard stratum is reached
2. They acts as a pillars supporting the super structure and transmitting the
load to the ground
FRICTION PILES –friction pile are used to transfer load carrying material by
means of skin friction along the length of piles.
Piles are driven at site where soil is weak or soft to a considerable depth and
it is not economical or rather possible to rest the bottom of pile on hard
stratum

17. COMPACTION PILES- when piles are driven into granular soil with the aim of
increasing the bearing capacity of soil. The piles are termed as compaction
piles
OR
Compaction piles are used to compact loose granular soil, thus increasing
their bearing capacity. The compaction piles do not carry any load hence they
may be made of weaker material ,sometime of sand only

18. TENSION PILE /UPLIFT PILE - tension pile anchor down the structure
subjected to uplift due to hydrostatic pressure or due to over turning
moment.
ANCHOR PILES – it provide anchorage against horizontal pull from sheet
piling or other pulling forces
FENDER PILES – it is used to protect water from structure against impact from
ships or other floating objects .
SHEET PILES – It is commonly used as bulkheads, or as impervious cut off to
reduce seepage and uplift under hydraulic structure.

19. Classification based on material used
1. CONCRETE PILES- Concrete piles are either precast or cast in situ. Precast
piles are cast and cured at the casting site and then transported to the
site for installation. These piles are adequately reinforced to with stand
handling stresses along with working stresses. Precast piles are normally
suitable for short lengths. Cast-in-situ piles are constructed by drilling
hole in the ground and then filling the hole by concrete after placing the
reinforcement.
2. TIMBER PILES - Timber piles are made from tree trunks and are well
seasoned, straight and free from all defects. In India, timber piles mostly
made up of sal tree trunks. These piles are available in length between 4
to 6 m. Timber piles are used where good bearing stratum is available at a
relatively shallow depth.

21. 3. Steel piles – they are usually of rolled H-sections or thick pipe sections.
These piles are used to withstand large impact stresses and where less
distributance from driving is desired. Steel sheet piles and H-piles are
generally used to support the open excavation and to provide seepage
barrier.
4. COMPOSITE PILE - A pile which is made up of two materials like concrete
and timber or concrete and steel is called composite pile. Composite piles
are used in situations where a part of the pile is permanently under water.
The part of the pile which will be under water can be made of untreated
timber and the other part can be of concrete.