A foundation is the lowest part of the building structure. It is the engineering field of study devoted to the design of those structures which support other structures, most typically buildings, bridges or transportation infrastructure. It is at the periphery of Civil, Structural and Geo-technical Engineering disciplines and has distinct focus on soil-structure interaction.

1. FOUNDATION & FOOTING
COURSE CODE : CE – 200
COURSE TITLE : DETAILS IN CONSTRUCTION & ESTIMATING
DEPT. OF CIVIL ENGINEERING, CUET

2. WHAT IS FOUNDATION ?
According to Wikipedia, A foundation is the element of
an architectural structure which connects it to the ground,
and transfers loads from the structure to the ground.
It is a complex term used in geotechnical engineering to
denote the soil and footing and their interaction that
provides bearing capacity as well as settlement resistance
to the super structure.
Specially designed foundation helps in avoiding the lateral
movements of the supporting material.
Fig. 1- Concrete frame structures with
foundation.

3. WHAT IS FOOTING ?
• "Footing" is defined as a structure constructed in
brickwork, masonry or concrete under the base of
a wall or column for the purpose of distributing
the load over a larger area.
• It is more from a structural aspect that would
transfer the axial load from the column to the soil.
Footing can be idealized during analysis as
supports.
• The purpose of footings is to support
the foundation and prevent settling.
Fig. 2- Footings supporting the foundation.

4. WHY FOUNDATION & FOOTINGS ?
No. 1
To distribute the weight of the structure over large
area so as to avoid over-loading of the soil beneath.
No. 2
To load the sub-stratum evenly and thus prevent
unequal settlement.
No. 3
To take the structure deep into the ground and thus
increase its stability, preventing overloading.
Fig. 3- Consecutive process of building a
house.

5. TYPES OF FOOTINGS
 ISOLATED FOOTING
 COMBINED FOOTING
 MAT or RAFT FOOTING
 PILE FOUNDATION
 PILE RAFT FOUNDATION
 SHORE PILE or SHEET PILE PROTECTION SYSTEM

6. ISOLATED FOOTING

7. ISOLATED FOOTING
Fig. 4 – Isolated Footing.
Captured from the Water
Tank area of CUET where
Engineering Office cum
Central Parking is going to
be built.
This picture was captured on
October 4, at 6 : 30 am

8. ISOLATED FOOTING
• DEFINITION :
Isolated footing is defined as the footing,
which is provided beneath the column to
distribute the loads safely to the bed soil.
This kind of footing is used to support
single-columns and when the columns are
arranged relatively at long distance.
Fig. 5- Detailed Layout

9. AREA OF APPLICATION
 Commonly used for shallow foundations in
order to carry and spread concentrated loads,
caused for example by columns or pillars.
 Isolated footings can consist either of
reinforced or non-reinforced material. For the
non-reinforced footing however, the height of
the footing has to be bigger in order to provide
the necessary spreading of load.
 Should only be used when it is absolutely
certain, that no varying settlements will occur
under the entire building. Spread footings are
unsuitable for the bearing of widespread loads.
In this case, either strip (continuous)
Fig. 6- Steel framework for isolated
footing.

10. COMBINED FOOTING

11. COMBINED FOOTING
• DEFINITION :
A strap footing is a component of a building's
foundation. It is a type of combined footing,
consisting of two or more
column footings connected by a concrete
beam.
Fig. 7- Combined footing.

12. AREA OF APPLICATION
 The distance between two columns is small and when
soil bearing capacity of soil is lower and their footings
overlap with each other.
When one column is close to a property line or sewer
pipe, the centre of gravity of column will not coincide
with footing. In such cases, it is necessary to provide
combined this footing with that of the adjacent internal
column.
 Dimensions of one side of footing are restricted to some
lower value so that column footings may be combined
Fig. 8- Steel framework for combined
footing using AutoCAD.

13. MAT OR RAFT FOUNDATION

14. MAT OR RAFT FOUNDATION
Fig. 9- Mat Foundation of a site. Fig. 10- Layout of Raft Foundation using AutoCAD.

15. MAT OR RAFT FOUNDATION
• DEFINITION :
According to the Dictionary of Earth Sciences,
Raft foundation, a type of foundation, used for
heavy loading, or construction on soft ground,
composed of a continuous slab of
reinforced concrete below the entire surface.
In Venice, many of the mediaeval raft foundations
underneath the large churches are made of wood.
Fig. 11- Raft Foundation of a site.

16. AREA OF APPLICATION
Raft foundations may be used for buildings on compressible ground
such as very soft clay, alluvial deposits and compressible fill material
where strip, pad or pile foundations would not provide a stable
foundation without excessive excavation. The reinforced concrete raft
is designed to transmit the whole load of the building from the raft to
the ground where the small spread loads will cause little if any
appreciable settlement.

17. Pile foundation

18. PILE FOUNDATION
Fig. 12- Pile Foundation of a site. Fig. 13- Pile Heads found at a site.

19. PILE FOUNDATION
• DEFINITION :
• Pile foundation, a substructure in
which piles are used to transfer a load from a
structure to the soil. Pile foundations are
particularly appropriate when the building or
structure is to be erected on soil that is not
stable or is saturated with water.
Fig. 14- Simple sketch of pile foundation

20. AREA OF APPLICATION
It is used
• When stratum of required bearing capacity is at greater depth.
• Where the soil is compressible.
• Where the soil is water-logged.
• Where the soil is of made-up type.
EXAMPLES :
• Foundation of heavy bridges, high-rise buildings
• Water front installations (pier, wharf, docks etc.)

21. Piled raft foundation

22. PILED RAFT FOUNDATION
Fig. 15- Piled Raft Foundation on AutoCAD. Fig. 16- A part of Piled
Raft Foundation.

23. PILED RAFT FOUNDATION
• DEFINITION :
• The combined pile raft foundation (CPRF) is a
geotechnical composite construction that
combines the bearing effect of both
foundation elements raft and piles by taking
into account interactions between
the foundation elements and the subsoil.

24. AREA OF APPLICATION
• The addition of piles to a raft increases the effective size of a foundation and can help
resist horizontal loads. This can improve the performance of the foundation in reducing the amount
of settlement and differential settlement, as well as improving the ultimate load capacity.
• Piled raft foundations are typically used for large structures, and in situations where soil is not
suitable to prevent excessive settlement. They are an increasingly popular choice for high-rise
buildings.
• During the design process, the optimum number and position of piles, as well as their
diameter, reinforcement and length, is determined to ensure the stability of the structure while
providing an economical solution, with the raft and piles acting together to ensure the
required settlement is not exceeded.

25. Shore pile or sheet pile protection system

26. SHORE PILE OR SHEET PILE PROTECTION SYSTEM
Fig. 18- Shore Pile
Protection System.
Location : Madunaghat
Water Treatment Plant,
Madunaghat, Hathajari,
Chittagong.
This photo was captured on
March 2018.

27. SHORE PILE OR SHEET PILE PROTECTION SYSTEM
Fig. 19 & 20- From these two images we see that the site areas are surrounded by sheet pile
protection system.

28. SHORE PILE OR SHEET PILE PROTECTION SYSTEM
• DEFINITION :
• SHORE PILES are generally piles sunken
support for building: A vertical wood, metal, or
concrete support for a building or other structure
that is driven into the ground shore piling is a
commonly used term before installation of the
mat foundation of the building needs to be done.
Fig. 21- This type of shore piles were made for
making piers during the construction of
Bohoddarhat Flyover at Chittagong.

29. AREA OF APPLICATION
• When construction is taking place in a confined space, then temporary walls are used to
prevent cave-ins; offering protection to the workers working in the vicinity of the area.
• In a home environment, sheet piling is used as permanent walls as they provide stability and
durability to the interior walls (especially basement walls).
• Pilling is also used to prevent floods to structures close to shorelines.
• To protect foundations from water damage.
• To support excavations for parking structures, basements, foundations, pump houses, and to
construct cofferdams, seawalls and bulkheads