Ramchandra seminar report doc

SIET/2016/16ESFCE024/8CESR 1 | P a g e
A
Seminar Report
On
“To Study of Foundation and its types”
Submitted In partial fulfilment for the award of the degree of
Bachelor of Technology
In
Department of Civil Engineering
2016 - 2020
Submitted To: Submitted By:
Mr. Ramprasad Kumawat Ramchandra Verma
(HoD) 16ESFCE024
Guided by :
Mr. Sunil Kumar
Assistance Professor
Department of Civil Engineering
Shekhawati Institute of Engineering & Technology
Sikar, Rajasthan

CERIFICATE
I hereby, certify that the work, which is being presented in the Seminar Report, entitled “To
Study of foundation and it’s types” In partial fulfilment of the requirement for the
award of Degree of B.Tech in Civil Engineering, submitted in the Department of Civil
Engineering of Shekhawati Institute of Engineering and Technology, Sikar affiliated to
Rajasthan Technical University, Kota, Rajasthan.
Submitted To: Guided By:
Mr. Ramprasad Kumawat Mr. Sunil Kumar
Professor & HoD Assistant Professor
Department of CE SIET Department of CE SIET

CONTENT
Sr. No. Title Page No.
1. INTRODUCTION 06
2. FOUNDATION DESIGN PRINCIPLES 07
3. FUNCTIONS OF FOUNDATION 10
4. TYPES OF FOUNDATION 11
SHALLOW FOUNDATION 12
DEEP FOUNDATION 18
PILE FOUNDATION 19
CLASSIFICATION OF PILE FOUNDATION 24
5. SAFE BEARING CAPACITY OF SOIL 25
6. DEPTH OF FOUNDATION 26
7. SOIL PROPERTIES AND PARAMETERS, AND
FOUNDATION SYSTEMS
27
8. DISTRIBUTION OF BASE PRESSURE 29
9. MATERIALS USED FOR FOUNDATION 31
10. CONCLUSION 34
11. REFERENCE 35

LIST OF FIGURE
Figure No. Description Page no.
1 Isolated footing 13
2 Wall footing 14
3 Combined Footing 15
4 Cantilever or Strap Footing 16
5 Raft Footing 17
6 Basic Principles of Pile Foundation 19
7 End Bearing Piles 20
8 Friction Piles 20
9 Pile foundation 21
10 Axial Compressive Load transfer in deep foundations 22
11 Axial Tension Load transfer in deep foundations 22
12 Pile Foundation 5
13 Capillary action 28
14 Pressure Distribution in sandy soil 29
15 Pressure Distribution in Clayey soil 30
16 Assuming uniform pressure in the design 30
17 Cement 31
18 Aggregate 32
19 Steel 33
20 Concrete 33

ABSTRACT
The advanced world experience in the construction of high-rise buildings is analysed.
It is emphasized that modular construction has the potential to shorten project design and
engineering time, reduce costs and improve construction productivity. Structures that are
used for the transfer of loads from the superstructure to the sub surface strata are known as
Foundation. And Piles are a type of foundation. For a hydraulic structure such as bridges,
dams, etc. or for surfaces having high water content, the piles are driven into the ground and
under the water strata. Piles normally used in underwater structures are subjected to
corrosion. Corrosion reduces the structures stability and longevity. There is absolutely no
method for elimination of corrosion; but corrosion protection measures can be employed for
controlling the effects of corrosion. Corrosion protection can be done in different ways,
depending on the environment and other atmospheric and hydrological factors. Types of
corrosion protection include – treatment of surfaces, utilization of inhibitors, use of coatings
and sealants, cathodic and anodic protection.

CHAPTER 1
INTRODUCTION
Till now we discussed the different structural elements viz. beams, slabs, staircases and
columns, which are placed above the ground level and are known as superstructure. The
superstructure is placed on the top of the foundation structure, designated as substructure as
they are placed below the ground level.
The elements of the superstructure transfer the loads and moments to its adjacent element
below it and finally all loads and moments come to the foundation structure, which in turn,
transfers them to the underlying soil or rock. Thus, the foundation structure effectively
supports the superstructure. However, all types of soil get compressed significantly and cause
the structure to settle. Accordingly, the major requirements of the design of foundation
structures are the two as given below (see cl.34.1 of IS 456):
1. Foundation structures should be able to sustain the applied loads, moments, forces and
induced reactions without exceeding the safe bearing capacity of the soil.
2. The settlement of the structure should be as uniform as possible and it should be within
the tolerable limits. It is well known from the structural analysis that differential
settlement of supports causes additional moments in statically indeterminate structures.
Therefore, avoiding the differential settlement is considered as more important than
maintaining uniform overall settlement of the structure.
In addition to the two major requirements mentioned above, the foundation structure
should provide adequate safety for maintaining the stability of structure due to either
overturning and/or sliding (see cl.20 of IS 456). It is to be noted that this part of the structure
is constructed at the first stage before other components (columns / beams etc.) are taken up.
So, in a project, foundation design and details are completed before designs of other
components are undertaken.
However, it is worth mentioning that the design of foundation structures is somewhat
different from the design of other elements of superstructure due to the reasons given below.
Therefore, foundation structures need special attention of the designers.

1. Foundation structures undergo soil-structure interaction. Therefore, the behaviour of
foundation structures depends on the properties of structural materials and soil.
Determination of properties of soil of different types itself is a specialized topic of
geotechnical engineering. Understanding the interacting behaviour is also difficult.
Hence, the different assumptions and simplifications adopted for the design need
scrutiny. In fact, for the design of foundations of important structures and for difficult
soil conditions, geotechnical experts should be consulted for the proper soil
investigation to determine the properties of soil, strata wise and its settlement criteria.
2. Accurate estimations of all types of loads, moments and forces are needed for the
present as well as for future expansion, if applicable. It is very important as the
foundation structure, once completed, is difficult to strengthen in future.
3. Foundation structures, though remain underground involving very little architectural
aesthetics, have to be housed within the property line which may cause additional
forces and moments due to the eccentricity of foundation.
4. Foundation structures are in direct contact with the soil and may be affected due to
harmful chemicals and minerals present in the soil and fluctuations of water table
when it is very near to the foundation. Moreover, periodic inspection and maintenance
are practically impossible for the foundation structures.
5. Foundation structures, while constructing, may affect the adjoining structure forming
cracks to total collapse, particularly during the driving of piles etc.
However, wide ranges of types of foundation structures are available. It is very
important to select the appropriate type depending on the type of structure, condition of
the soil at the location of construction, other surrounding structures and several other
practical aspects as mentioned above.

CHAPTER 2
FOUNDATION DESIGN PRINCIPLES
The main objectives of foundation design are to:
Ensure that the structural loads are transmitted to the subsoil safely, economically and
without any unacceptable movement during the construction period and throughout the
anticipated life of the building or structure.
Basic Design Procedure
Assessment of site conditions in the context of the site & soil investigation report
Calculation of anticipated structural loading
Choosing the foundation type, should consider:
Soil condition
Type of structure
Structural loading
Economic factors
Time factors relative to the proposed contract period
Construction problem
Sizing the chosen foundation in the context of loading,
ground bearing capacity & any likely future movement of
the building / structure

CHAPTER 3
FUNCTIONS OF FOUNDATION
1. Distribution of loads
2. Stability against sliding & overturning
3. Minimize differential settlement
4. Safe against undermining
5. Provide level surface
6. Minimize distress against soil movement
1. Distribution of loads:
 Foundation help to distribute the loads of super-structure to a large of the soil
 Therefore, the intensity of load at its base does not exceed the safe bearing capacity of
the soil
 In the case of deep foundations, the super imposed loads are transmitted either
through end bearing or both by side friction & end bearing
2. Stability against sliding & overturning:
 Foundation imparts lateral stability to the super structure by anchoring it to the ground
 It increases the stability against sliding & overturning due to horizontal forces to
wind, earthquake, etc.
3. Minimize differential settlement:
 Foundation distribute the super-imposed loads evenly on the sub-soil, even in the case
of non-uniform loads
 This can be achieved by constructing combined footing or raft foundation

4. Safe against undermining:
 Foundation provides safety against scouring or undermining by flood water or
burrowing animals.
5. Minimize distress against soil movement:
 Distress or failure due to expansion or contraction of the sub-soil due to moisture
variation in clayey & black cotton soils are minimized by the provision of special type
foundations

CHAPTER 4
TYPES OF FOUNDATION
The foundations of the building transfer the weight of the building to the ground.
While 'foundation' is a general word, normally, every building has a number of individual
foundations. Most buildings have some kind of foundation structure directly below every
major column, so as to transfer the column loads directly to the ground.
A foundation (or, more commonly, foundations) is the element of an architectural
structure which connects it to the ground, and transfers loads from the structure to the ground.
Foundations are generally considered either shallow or deep.
Types of Foundation

1. Shallow Foundations:
Shallow foundations are used when the soil has sufficient strength within a short depth
below the ground level. They need sufficient plan area to transfer the heavy loads to the base
soil. These heavy loads are sustained by the reinforced concrete columns or walls (either of
bricks or reinforced concrete) of much less areas of cross-section due to high strength of
bricks or reinforced concrete when compared to that of soil. Shallow foundations are also
designated as footings. The different types of shallow foundations or footings are discussed
below.
Shallow Foundations are usually located no more than 3M below the lowest finished
floor. A shallow foundation system generally used when -
 The soil close the ground surface has sufficient bearing capacity, and
 Underlying weaker strata do not result in undue settlement. The shallow foundations
are commonly used most economical foundation systems.
Footings are structural elements, which transfer loads to the soil from columns, walls or
lateral loads from earth retaining structures. In order to transfer these loads properly to the
soil, footings must be design to
 Prevent excessive settlement
 Minimize differential settlement, and
 Provide adequate safety against overturning and sliding.
A. Isolated spread footings:
Isolated spread footings under individual columns. These can be square, rectangular, or
circular. Isolated spread footings are very economical for columns of small loads.
 Suitable for most subsoil except loose sand, loose gravels and fill areas
 Usually constructed of reinforced concrete, square in plan

Fig.1 - Isolated footing

B. Wall footing
Wall footing is a continuous slab strip along the length of wall. These are in long strips
especially for load bearing masonry walls or reinforced concrete walls. However, for load
bearing masonry walls, it is common to have stepped masonry foundations. The strip footings
distribute the loads from the wall to a wider area and usually bend in transverse direction.
Accordingly, they are reinforced in the transverse direction mainly, while nominal
distribution steel is provided along the longitudinal direction.
Fig.2 - Wall footing

C. Combined Footing:
When the spacing of the adjacent columns is so close that separate isolated footings are not
possible due to the overlapping areas of the footings or inadequate clear space between the
two areas of the footings, combined footings are the solution combining two or more
columns. Combined footing normally means a footing combining two columns. Such
footings are either rectangular or trapezoidal in plan forms with or without a beam joining the
two columns.
Combined footings support two or more columns. These can be rectangular or
trapezoidal plan.
Fig.3 Combined Footing

D. Cantilever or strap footings:
These are similar to combined footings, except that the footings under columns are
built independently, and are joined by strap beam.
When two isolated footings are combined by a beam with a view to sharing the loads
of both the columns by the footings, the footing is known as strap footing. The connecting
beam is designated as strap beam. These footings are required if the loads are heavy on
columns and the areas of foundation are not overlapping with each other.
Fig.4 – Cantilever or Strap Footing

E. Raft or Mat foundation:
This is a large continuous footing supporting all the columns of the structure. This is
used when soil conditions are poor but piles are not used.
These are special cases of combined footing where all the columns of the building are
having a common foundation. Normally, for buildings with heavy loads or when the soil
condition is poor, raft foundations are very much useful to control differential settlement and
transfer the loads not exceeding the bearing capacity of the soil due to integral action of the
raft foundation. This is a threshold situation for shallow footing beyond which deep
foundations have to be adopted.
 Used to spread the load of the structure over a large base to reduce the load per unit
area being imposed on the ground
 Particularly useful where low bearing capacity soils are encountered & where
individual column loads are heavy
Fig.5 – Raft Footing

2. Deep Foundation:
The shallow foundations may not be economical or even possible when the soil bearing
capacity near the surface is too low. In those cases deep foundations are used to transfer loads
to a stronger layer, which may be located at a significant depth below the ground surface. The
load is transferred through skin friction and end bearing.
As mentioned earlier, the shallow foundations need more plan areas due to the low
strength of soil compared to that of masonry or reinforced concrete. However, shallow
foundations are selected when the soil has moderately good strength, except the raft
foundation which is good in poor condition of soil also. Raft foundations are under the
category of shallow foundation as they have comparatively shallow depth than that of deep
foundation. It is worth mentioning that the depth of raft foundation is much larger than those
of other types of shallow foundations.
However, for poor condition of soil near to the surface, the bearing capacity is very less
and foundation needed in such situation is the pile foundation. Piles are, in fact, small
diameter columns which are driven or cast into the ground by suitable means. Precast piles
are driven and cast-in-situ are cast. These piles support the structure by the skin friction
between the pile surface and the surrounding soil and end bearing force, if such resistance is
available to provide the bearing force. Accordingly, they are designated as frictional and end
bearing piles. They are normally provided in a group with a pile cap at the top through which
the loads of the superstructure are transferred to the piles.
Piles are very useful in marshy land where other types of foundation are impossible to
construct. The length of the pile which is driven into the ground depends on the availability
of hard soil/rock or the actual load test. Another advantage of the pile foundations is that they
can resist uplift also in the same manner as they take the compression forces just by the skin
friction in the opposite direction.
However, driving of pile is not an easy job and needs equipment and specially trained
persons or agencies. Moreover, one has to select pile foundation in such a situation where the
adjacent buildings are not likely to be damaged due to the driving of piles. The choice of
driven or bored piles, in this regard, is critical.

PILE FOUNDATION
 Piles are structural members that are made of steel, concrete, and/or timber. They are used
to build pile foundations, which are deep and which cost more than shallow foundations.
 Our building is rested on a weak soil formation which can’t resist the loads coming from
our proposed building, so we have to choose pile foundation.
 Can be defined as a series of columns constructed or inserted into the ground to transmit
the loads of a structure to a lower level of subsoil
 Can be used when suitable foundation conditions are not presented at or near ground level
Classification of piles (may be classified by their basic design function or method of
construction):
 End bearing piles
 Friction or floating piles
 Replacement piles
 Displacement piles
Basic Principles of Pile Foundation
Fig. 6 Basic Principles of Pile Foundation

Piles can be divided in to two major categories:
1. End Bearing Piles
If the soil-boring records presence of bedrock at the site within a reasonable depth,
piles can be extended to the rock surface. End bearing pile rests on a relative firm soil. The
load of the structure is transmitted through the pile into this firm soil or rock because the base
of the pile bears the load of the structure, this type of pile is called end bearing pile.
2. Friction Piles
When no layer of rock is present depth at a site, point bearing piles become very long and
uneconomical. In this type of subsoil, piles are driven through the softer material to specified
depths.
Fig. 7 End Bearing Piles
Fig. 8 Friction Piles

Fig.9 – Pile foundation

Fig.10 - Axial Compressive Load transfer in deep foundations
Fig11. - Axial Tension Load transfer in deep foundations

Fig.12 Pile Foundation- (a) Vertical Piles; (b) Battered Piles

CLASSIFICATION OF PILES
1. Based on material
 Concrete
 Steel
 Timber
2. Based on method of construction/installation
 Driven/Displacement pre cast Piles.
 Driven/Displacement cast in situ Piles.
 Bored/Replacement pre cast situ.
 Bored/Replacement cast in situ piles.
3. Based on load transfer mechanism
 End bearing Piles
 Friction/floating Piles
 Bearing cum friction Pile
4. Based on sectional area
 Circular
 Square
 H
 Octagonal
 Tubular
5. Based on size
 Micro piles dia.<150 mm
 Small dia.>150 mm and <600mm
 Large dia. Piles>600mm
6. Based on inclination
 Vertical Piles
 Inclined/raker Piles

CHAPTER 5
SAFE BEARING CAPACITY OF SOIL
The safe bearing capacity qc of soil is the permissible soil pressure considering safety
factors in the range of 2 to 6 depending on the type of soil, approximations and assumptions
and uncertainties. This is applicable under service load condition and, therefore, the partial
safety factors λf for different load combinations are to be taken from those under limit state of
serviceability(vide Table 18 of IS 456 or Table 2.1 of Lesson 3). Normally, the acceptable
value of qc is supplied by the geotechnical consultant to the structural engineer after proper
soil investigations. The safe bearing stress on soil is also related to corresponding permissible
displacement / settlement.
Gross and net bearing capacities are the two terms used in the design. Gross bearing
capacity is the total safe bearing pressure just below the footing due to the load of the
superstructure, self weight of the footing and the weight of earth lying over the footing. On
the other hand, net bearing capacity is the net pressure in excess of the existing overburden
pressure. Thus, we can write
Net bearing capacity = Gross bearing capacity - Pressure due to overburden soil
While calculating the maximum soil pressure q, we should consider all the loads of
superstructure along with the weight of foundation and the weight of the backfill. During
preliminary calculations, however, the weight of the foundation and backfill may be taken as
10 to 15 per cent ofthe total axial load on the footing, subjected to verification afterwards.

CHAPTER 6
DEPTH OF FOUNDATION:
All types of foundation should have a minimum depth of 50 cm as per IS 1080-1962.
This minimum depth is required to ensure the availability of soil having the safe bearing
capacity assumed in the design. Moreover, the foundation should be placed well below the
level which will not be affected by seasonal change of weather to cause swelling and
shrinking of the soil. Further, frost also may endanger the foundation if placed at a very
shallow depth. Rankine formula gives a preliminary estimate of the minimum depth of
foundation and is expressed as
d = (qc/λ) {(1 - sin φ)/(1 + sin φ)}2
where d = minimum depth of foundation
qc= gross bearing capacity of soil
λ = density of soil
φ = angle of repose of soil
Though Rankine formula considers three major soil properties qc, λ and φ , it does
not consider the load applied to the foundation. However, this may be a guideline for an
initial estimate of the minimum depth which shall be checked subsequently for other
requirements of the design.

CHAPTER 7
SOIL PROPERTIES AND PARAMETERS, AND FOUNDATION
SYSTEMS
Frost Depth (Frost Line or Freezing Depth): –
Frost Depth is the depth to which the groundwater in soil is expected to freeze due to
temperature drop.
 The frost line varies by latitude; it is deeper closer to the poles.
 It ranges in the United States from about zero to six feet.
 Below that frost depth the temperature varies, but is always above 0 °C (32 °F).
 In Arctic and Antarctic locations the freezing depth is so deep that it becomes year-
round permafrost, and the term "thaw depth" is used instead.
Frost heaving: -
 Frost heaving is an upwards swelling of soil during freezing conditions caused by an
increasing presence of ice as it grows towards the surface.
 Ice growth requires a water supply that delivers water to the freezing front via capillary
action in certain soils.
 The weight of overlying soil restrains vertical growth of the ice and can promote the
formation of lens-shaped areas of ice within the soil.
 Yet the force of one or more growing ice lenses is sufficient to lift a layer of soil, as much
as 30 cm or more.
 The soil through which water passes to feed the formation of ice lenses must be
sufficiently porous to allow capillary action, yet not so porous as to break capillary
continuity. Such soil is referred to as "frost susceptible".
 Differential frost heaving can crack pavements—contributing to springtime pothole
formation and damage building foundations.

Capillary action: -
Capillary action (capillarity, capillary motion, or wicking) is the ability of a liquid to flow in
narrow spaces without the assistance of, and in opposition to, external forces like gravity.
If the diameter of the tube is sufficiently small, then the combination of surface tension
caused by cohesion within the liquid and adhesive forces between the liquid and the tube act
to lift the liquid (Figure).
The capillary action is due to the pressure of cohesion and adhesion, which cause the liquid to
work against gravity.
Fig.13 Capillary action

CHAPTER 8
DISTRIBUTION OF BASE PRESSURE: -
The foundation, assumed to act as a rigid body, is in equilibrium under the action of
applied forces and moments from the superstructure and the reactions from the stresses in the
soil. The distribution of base pressure is different for different types of soil. Typical
distributions of pressure, for actual foundations, in sandy and clayey soils. However, for the
sake of simplicity the footing is assumed to be a perfectly rigid body, the soil is assumed to
behave elastically and the distributions of stress and stain are linear in the soil just below the
base of the foundation, as shown in Fig.11.28.19. Accordingly, the foundation shall be
designed for the applied loads, moments and induced reactions keeping in mind that the safe
bearing capacity of the soil is within the prescribed limit. It is worth mentioning that the soil
bearing capacity is in the serviceable limit state and the foundation structure shall be designed
as per the limit state of collapse, checking for other limit states as well to ensure an adequate
degree of safety and serviceability.
Fig.14 – Pressure Distribution in sandy soil

Fig.15 – Pressure Distribution in Clayey soil
Fig16. – Assuming uniform pressure in the design

CHAPTER 9
MATERIALS USED FOR FOUNDATION
 Foundation must be constructed of a durable material of an adequate strength
 The most suitable material is concrete. But now-a-days RCC is best choice
 Concrete is a mixture of cement, aggregates & water in a controlled proportion
CEMENT:
 Manufactured from clay & chalk
 Act as a binder of the concrete mix
 Cement can be supplied in bags ( 1 bag = 50kg) or in bulk
 Air tight sealed bags requiring a dry dump free store
 Bulk cement delivered by tanker (12 to 50 tonnes) & pumped into storage silo
Fig.17 – Cement
AGGREGATES:
 2 types of aggregates: coarse & fine aggregates
 Coarse aggregate is defined as a material which is retained on a 5mm sieve

 Fine aggregate is defined as a material which is passes a 5mm sieve
 Aggregate can be either:
 Natural rock which has disintegrated
 Crushed stone
 Gravels
Fig.18 – Aggregates
WATER:
 Must be of a good quality fit for drinking
 Water is added to start the chemical reaction & to give workability
 The amount of water used is called the water/cement ratios, usually about 0.4 to 0.5
 Too much water will produce a weak concrete mix of low strength
 Whereas too little water will produce a concrete mix of low & inadequate workability.
STEEL
Characteristics
Strength: 40 grade, 60 grade etc.
Corrosion
Mould: deformed bar

Fig.19 – Steel
CONCRETE MIX:
 This concrete mix expressed as a ratio, e.g.,
1:2:4 or 1:3:6/20mm, which means
1 part of cement
3 parts of fine aggregates
6 parts of coarse aggregate
20mm – maximum size of coarse aggregate for the mix
Fig.20 – Concrete

CHAPTER 10
CONCLUSION
This lesson explains the two major and other requirements of the design of foundation
structures. Various types of shallow foundations and pile foundation are discussed explaining
the distribution of pressure in isolated footings loaded concentrically and eccentrically with e
≤ L/6 and e > L/6. The gross and net safe bearing capacities are explained.
All the discussions are relevant in understanding the load carrying mechanism of the
foundation and the behaviour of soil.

REFERENCE
A. www.wikipedia.com
1. Crabtree, Pam J.. Medieval archaeology: an encyclopedia. New York: Garland Pub
2. Edwards, Jay Dearborn, and Nicolas Verton. A Creole lexicon architecture,
landscape, people. Baton Rouge: Louisiana State University Press
3. Nicholson, Peter. Practical Masonry, Bricklaying and Plastering, Both Plain and
Ornamental. Thomas Kelly: London.
B. www.en.wikiversity.org
1. Terzaghi, K., Peck, R.B. and Mesri, G. (1996), Soil Mechanics in Engineering
Practice 3rd Ed., John Wiley & Sons
C. Indian Standard Code :
 IS 1893–2002
 IS 13827–1992
 IS: 13920–1997
 IS: 456-2000
 IS 1080-1985

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