Hi everyone thanks for you to see our report again, and our report contains every single information about deep foundation just like advantages and disadvantages and types and here again just like the shallow foundation report we compared both with each other. And from this link you read about shallow foundation https://www.slideshare.net/mobile/AliRizgar/shallow-foundation-full-information And from this email you can ask any thing to us  Alirizgar234@gmail.com

1. Salahaddin University -Erbil
College of Engineering
Civil Engineering Department
Foundation
(Deep Foundation)
By
Yousif Majed
Yousif Imad
Hanan F. Sulaqa
Supervisor
Zina M. Mudheher
Ali Rizgar
April, 2019

2. Page | 1
Abstract
This report presents a full discussion about all of the deep foundation
types. The basis of the report is to explain how this system works and
why it might be advantageous or not, compared to other types of deep
foundation. It will help in giving an insight on the stages of drilling. The
main reason for this report is because it is important in later stages of
civil engineering in specifics. As next year one of the subjects we will talk
about is about foundation and most of ideas come for the 2nd year civil
engineering. Our aim is to help the audience know the difference
between deep and shallow foundation. Also give probable reason to why
deep foundation is used. We found that deep foundation is used for
heavy duty and deep construction We recommend before choosing what
kind foundation to hire a professional who has to measure the depth
required to sustain the construction.

3. Page | 2
Table of Contents
Body of the report
1.0 Introduction to foundation………………………………..………….................p3
2.0 Definition of Deep foundation…………………………………………………..p4
3.0 Types of deep foundation ………………………………………………………p5
3.1 Basements……………………………………………………………..………...p6
3.2 Buoyancy rafts/ hollow box foundation…………………………………….…p6
3.3 Caisson foundation……………………………………………………………...p8
3.4 Cylinders………………………………………………………………………….p9
3.5 Shaft foundation………………………………………………………………... p10
3.6 Pile foundation …………………………………………………………………..p11
4.0 differences & advantage/disadvantage of deep & shallow foundation…… p13
5.0 calculation and equations ……………………………………………………...p15
6.0 conclusions……………………………………………………………………….p18
7.0 recommendations ……………………………………………………………….p18

4. Page | 3
1.0 Introduction to Foundation
A foundation is a lower portion of building structure that
transfers its gravity loads to the earth. Foundations are
generally broken into two categories: shallow foundations and
deep foundations. To make a foundation, we normally dig a
trench in the ground, digging deeper and deeper until we
come to subsoil, which is more solid than the topsoil that is
used to grow plants and crops. When the trench is deep
enough, we fill it with any strong, hard material we can find.
Sometimes we pour in concrete into the trench, which we
strengthen even more by first putting long thin round pieces of
steel into the trench. When the concrete dries, the steel acts
like the bones in our body to tie the foundation together. We
call this reinforced concrete.
Once the foundation has been packed down tightly, or dried
hard, we can begin to build the building superstructure. This
has been a brief insight about foundation and its type’s .we will
branch out for more types between the two. So basically we
will introduce you to all types of deep foundations and
everything that concerns about it.

5. Page | 4
2.0 Definition of Deep Foundation
Deep foundation is required to carry loads from a structure
through weak compressible soils or fills on to stronger and
less compressible soils or rocks at depth, or for functional
reasons. Deep foundations are founded too deeply below the
finished ground surface for their base bearing capacity to be
affected by surface conditions, this is usually at depths >3 m
below finished ground level.
Deep foundations are used where soil of adequate strength is
not available is not available close enough to the surface for
the use of shallow foundations. Also figure out Where the soil
near the surface is unsuitable.1
Deep foundation tends to drive through more than 3 m deep
underground and for that it costs more, takes more time, and
more work but has more integrity for heavy duty building.
These types are used for different kinds of situation as each
has its specialty.
1
Building construction ,principles materials, and system ,madan Mehta ,walter scarborough ,diane
armpriest,2009 update , book.

6. Page | 5
3.0 Types of Deep foundation
1. Basements
2. Buoyancy rafts (hollow box foundations)
3. Caissons
4. Cylinders
5. Shaft foundations
6. Pile foundations2
2
https://theconstructor.org/geotechnical/types-of-deep-foundation/7252/

7. Page | 6
3.1 Basement foundation
These are hollow substructures designed to provide working or storage
space below ground level. The structural design is governed
by their functional requirements rather than from
considerations of the most efficient method of resisting
external earth and hydrostatic pressures. They are
constructed in place in open excavations.
3
3.2 Buoyancy rafts or hollow box foundations
Buoyancy rafts or hollow box foundations also known as the
floating foundations is a type of deep foundation is used in
building construction on soft and weak soils. Types of
buoyancy foundations, their construction methods, and
advantages are discussed in this article.
The decision of construction of a deep foundation is taken
when the load has to be distributed to an area either with soft
3
https://theconstructor.org/geotechnical/types-of-deep-foundation/7252/

8. Page | 7
weak compressible soils or to reach strata that have strong
soil or rock or any other special concerns. One such generally
used a type of deep foundation is called as Hollow box
foundations or buoyancy rafts foundation.
These types of foundations are designed such a way that they
behave as buoyant (floating) substructures for the net loading
over it. Hence reducing the load intensity over the soil.
Advantages of Buoyant Raft Foundation
1. The building is elevated to a required height, which makes
them stay above high-water levels.
2. The chances of settlement are reduced. As the total weight
coming is equal to the excavated soil, there is no
settlement. A slight increase in this load would not bring any
drastic change in exceeding the settlement limit.
3. Watertight material for foundations would help in the
durability of the underground structure.
4. Foundation having a height of 3 or 4 floors are used for
skyscraper construction. This construction is found for
efficient than pile foundation in areas with very weak soils
for a larger depth.
Disadvantages of Buoyant Raft Foundation
1. As the depth of weak soil increases, the amount of excavation also
increases. In construction, the excavation process is an activity
found very costly.
2. Catastrophic Movement possibilities- These occur when the
excavation is done beyond the critical depth of stability.
3. Support of deep foundation may undergo settlement due to the
earth pressure it is subjected to, from the surrounding soft soils.

9. Page | 8
4. Space is wasted as hollow raft foundations cannot be used for any
other purpose.
5. Uplift pressure would affect the whole foundation arrangement.4
3.3 Caissons Foundations:
A caisson foundation also called as pier foundation is a
watertight retaining structure used as a bridge pier, in the
construction of a concrete dam, or for the repair of ships. It is a
prefabricated hollow box or cylinder sunk into the ground to
some desired depth and then filled with concrete thus forming
a foundation
The foundation system of and the soils beneath the building
prevent the complex from moving vertically. When a load is
placed on soil, most soils settle. This creates a problem when
the building settles but the utilities do not.
Even more critical than settlement is differential settlement.
This occurs when parts of your building settle at different
rates, resulting in cracks, some of which may affect the
structural integrity of the building.
Conversely, in some rare instances soils may swell, pushing
your building upwards and resulting in similar problems.
Therefore, the foundation system must work in tandem with
the soils to support the building.
4
https://theconstructor.org/geotechnical/buoyancy-rafts-hollow-box-foundations/15159/

10. Page | 9
This figure shows how caisson foundation works:
Advantages of Caissons:
1. Economics
2. Minimizes pile cap needs
3. Slightly less noise and reduced vibrations
4. Easily adaptable to varying site conditions
5. High axial and lateral loading capacity
Disadvantages of Caissons:
1. Extremely sensitive to construction procedures
2. Not good for contaminated sites
3. Lack of construction expertise
4. Lack of Qualified Inspectors5
5
https://theconstructor.org/geotechnical/caisson-types-construction-advantages/503/

11. Page | 10
3.4 Cylinders:
Small diameter concrete shafts comprising single open cells
and constructed in the same manner as caissons are usually
called cylinders. ... Cylinders constructed with precast
concrete rings are usually filled with reinforced concrete. So
basically, Cylinders are small single-cell caisson.
3.5 Shaft foundations
A drilled shaft, also known as drilled pier, drilled caisson,
caisson, bored pile, etc., is a versatile foundation system that
is used extensively on a worldwide basis. In its simplest form,
a drilled shaft is constructed by making a cylindrical
excavation, placing a reinforcing cage (when necessary), and
then concreting the excavation. With available drilling
equipment, shaft diameters up to 20 ft (6 m) and depths
exceeding 250ft (76 m) are possible. However, for most
normal applications, diameters in the range of 3 to 10 ft (1 to 3
m) are typical. This size versatility allows a single drilled shaft
to be used in place of a driven pile group and eliminates the
need for a pile cap. In addition, normal construction practices
for drilled shafts effectively eliminate the noise and strong
ground vibrations that develop during pile driving operations.
For these and other secondary reasons, drilled shafts have
become both the technical and economic foundation of choice
for many design applications. In fact, they have become the
dominant foundation type in many geologic settings around
the world.6
6
FRED H. KULHAWY, Ph.D., P.E.
Professor of Civil/Geotechnical Engineering
Cornell University

12. Page | 11
Advantages of drilled piers
1. A single drilled pier can take up the load of a group of piles.
2. They have higher resistance to lateral loads.
3. Compared to pile driving, equipment needed for drilled pier is
lighter and there is no noise during construction.
4. Ground heaving do not exist in the case drilled piers.
5. Inspection of base and sides of pier is easier.
6. Base of drilled pier provides greater bearing capacity and great
resistance to uplift.
7. They can be used even when the soil contains boulders.
Disadvantages drilled piers
1. The concreting requires stricter supervision. The quality of
concrete obtained is generally inferior to that in precast piles.
2. Deep excavation of drilled pier, if not properly supported, can
cause substantial subsidence and damage to adjoining structures.
3. Load tests are difficult in case of drilled piers.
4. More subsurface investigations are required in case of drilled
piers.
3.6 Pile foundation
Pile foundations are relatively long and slender members
constructed by driving preformed units to the desired founding
level, or by driving or drilling-in tubes to the required depth –
the tubes being filled with concrete before or during withdrawal
or by drilling unlined or wholly or partly lined boreholes which
are then filled with concrete.

13. Page | 12
7
Types of driven pile
Types of driven pile Suitable condition Unsuitable condition
Timber driven pile Suitable option for
temporary works or when
the load is small
Cannot be used when
loads are large. It may
suffer decaying if water
level fluctuates, and it is
not suitable for heavy
driven since it may
experience unseen
splitting.
Concrete driven pile Extra reinforcement
ration is needed to make
the pile withstand driven
force, it needs time after
casting to obtain
necessary strength and
hence there is a gap
between casting and
driven, and it may suffer
from unseen damage due
to driven forces.
Suitable for all loading
conditions, it can
withstand corrosive soils
Steel driven pile It is suitable for all It is subjected to
7
https://www.google.com/url?sa=i&source=images&cd=&cad=rja&uact=8&ved=2ahUKEwjg_cDWu-
bgAhVjMewKHcv8DVAQjRx6BAgBEAU&url=https%3A%2F%2Ftheconstructor.org%2Fgeotechnical%2Findi
an-standard-codes-on-pile-foundations%2F7331%2F&psig=AOvVaw2Lxj-
8PwDw8tf1cz3gTcMI&ust=1551719437789179

14. Page | 13
loading condition, it does
not suffer damages due
to driven forces, it can be
extended and cut down.
Considerable long driven
pile can be used by
welding on additional
length.
corrosion in marine
condition above soil level
and subsequently it
needs protection, And
long piles may go off the
line during driving8
This table helps us to distinguish which type of driven pile to use and
is suitable for certain.
Shallow foundation and deep foundation have several
differences. In the following table the main differences
between shallow and deep foundation are given:
Sources Shallow Foundation Deep Foundation
1 Definition Foundation which is
placed near the
surface of the earth or
transfers the loads at a
shallow depth is called
shallow foundation.
Foundation which is placed
at a greater depth or
transfers the loads to deep
strata is called deep
foundation.
2 The depth of
foundation
The depth of shallow
foundation is generally
about 3 meters or the
depth of foundation is
less than the footing
with.
Greater than shallow
foundation.
3 Cost Shallow foundation is
cheaper.
Deep foundations are
generally more expensive
than shallow foundation.
8
https://theconstructor.org/geotechnical/selection-of-type-of-pile-foundation/20751/

15. Page | 14
Sources Shallow Foundation Deep Foundation
4 Feasibility Shallow foundations
are easier to construct.
The construction process of
a deep foundation is more
complex.
5 Mechanism of
load transfer
Shallow foundations
transfer loads mostly
by end bearing.
Deep foundations rely both
on end bearing and skin
friction, with few exceptions
like end bearing pile.
6 Advantages Construction materials
are available, less
labor is needed,
construction procedure
is simple at an
affordable cost etc.
Foundation can be
provided at a greater depth,
Provides lateral support
and resists uplift, effective
when foundation at a
shallow depth is not
possible, can carry huge
load etc.
7 Disadvantage
s
Possibility of a
settlement, usually
applicable for
lightweight structure,
weak against lateral
loads etc.
More expensive, needs
skilled labors, complex
construction procedure,
can be time-consuming and
some types of deep
foundations are not very
flexible etc.
8 Types Isolated foundation,
strip foundation, mat
foundation, combined
foundation etc.
Pier foundation, pile
foundation, caissons etc.
9
9
https://civiltoday.com/geotechnical-engineering/foundation-engineering/180-difference-between-
shallow-and-deep-foundation

16. Page | 15
5.0 Calculation and equations
Vertically Loaded Piles
The total pile resistance may be split into components from the
base and the shaft. Consideration of static equilibrium then
gives the ultimate capacity as:
Pu = Psu + Pbu – W
Pu Ultimate load capacity of the pile
Pbu = Ultimate resistance at the base of the pile (Base resistance)
Psu = Ultimate side shear resistance on the pile shaft (Shaft resistance)
W = Self-weight of the pile
Base Resistance
In analysing pile behaviour it is conventional to express the
ultimate base resistance by
Pbu = Ab ( fb + po)

17. Page | 16
Ab = Plan area of the pile base
fb = Net ultimate resistance per unit area of the base
po = Overburden pressure at the level of the base
If the pile does not extend above the soil surface it is found
that the pile weight is usually similar to the force due to the
overburden pressure. Thus
W ≈ Ab po
and Pu = Psu + Ab fb
Side Resistance
As = Surface area of pile shaft in contact with the soil
= Average ultimate side resistance per unit area
In general, the side resistance will be a function of depth
below the surface, because both the undrained strength su
(short term undrained analysis) and the effective stresses
(long term analysis) increase with depth. The average shear
stress can be expressed mathematically as
where L is the length of the pile

18. Page | 17
Base resistance
This is a simple bearing capacity problem, that is
Where of is the ultimate bearing capacity. For a soil with fu = 0
the ultimate bearing capacity can be written
qf = Nc su + g D = Nc su + po
The net ultimate resistance is simply
fb = Nc su
and the ultimate base resistance approximately
Pbu = Ab (Nc su + po)
It is conventional to take cu = cub
where sub is the undrained shear strength of the soil at the
pile base and to assume fu is zero. The value of Nc can then
be obtained from Skempton’s chart (p28 Data Sheets) which is
applicable for Φu = 0.
When using this chart it is important to check the length to diameter
ratio L/D (D/B on the chart). It is normally assumed that pile bases
may be treated as deep foundations and that Nc = 9. However, if L/D
is less than 4, Nc will be lower than 9 as shown in the chart below and
the ultimate capacity will be similarly reduced.

19. Page | 18
6.0 Conclusion
From all the researches that were done, the researches give
an insight on what deep foundation is and how it subdivides to
have certain amount of types which are used for specified
situations. It can also show the differences between deep and
shallow foundation in detail to why one might be better put to
use than the other, as each has its functionalities.
7.0 Recommendation
As for every project to be done, we would propose for a
professional to equate the cost, time, and amount of work
/needed work in order to determine when to use deep or
shallow foundation .Also a planner, who calculates cost and
time because this information will help a lot as to when
investors might consider the construction of the project.