ARC 076: ARCHITECTURAL STRUCTURES
COLLEGE OF ENGINEERING AND ARCHITECTURE
T-TH/ 12:00 – 1:30 (UP-FB1-BSAR5-01)
Plate No.5
Different Types of Footing
03-1314-02012
FERRER, ZILDJIAN M.
Student
ENGR. ROBERT JR MANAOIS
Instructor
A.Y. 2023-2024
Types of Shallow Foundation/Footing
1. Isolated Spread Footing
This is the most widely recognized and most straightforward shallow
foundation type, as this is the most economical type. They are typically utilized
for shallow establishments to convey and spread concentrated burdens caused,
for instance, by pillars or columns. They are generally used for ordinary
buildings (Typically up to five stories).
Isolated footing comprises a foundation directly at the base of the
segment. Generally, every section has its footing. They straightforwardly
transfer the loads from the column to the soil. It might be rectangular, square, or
roundabout. It can comprise both reinforced and non-reinforced material.
To decide when to use shallow foundations, it is necessary to know when it is
economical. It is economical when: Fig.1: Isolated Spread Footing
The load of the structure is relatively low. Source: https://civiltoday.com
Columns are not closely placed.
The bearing capacity of the soil is high at a shallow depth.
2. Wall Footing or Strip footing
Wall footing is also known as continuous footing. This type is used to
distribute loads of structural or non-structural load-bearing walls to the ground in
such a way that the load-bearing limit of the soil isn't outperformed. It runs along
the direction of the wall. The width of the wall foundation is usually 2-3 times
the width of the wall.
The wall footing is a continuous slab strip along the length of the wall. Stone,
brick, reinforced concrete, etc. are used for the construction of wall foundations.
On account of block walls, the footing comprises a few courses of bricks,
the least course being generally double the expansiveness of the wall
Fig.2: Wall Footing or Strip Footing
above.
Source: https://civiltoday.com
On account of stone masonry walls, the counterbalances could be 15 cm,
with the statues of the course as 30 cm. Along these lines, the size of the
footings is marginally more than that of the block divider footings.
If the heap on the wall is substantial or the soil is of low bearing limit, this reinforced concrete
foundation type can be given.
Wall footing is economical when:
Loads to be transmitted are of small magnitude.
It is placed on dense sand and gravel.
3. Combined Footing
The combined footing is very similar to the isolated footing. When
the columns of the structure are carefully placed, or the bearing capacity of
the soil is low and their footing overlaps each other, combined footing is
provided. It is fundamentally a blend of different footings, which uses the
properties of various balances in a single footing dependent on the necessity
of the structure.
Combined foundations are economic when:
The columns are placed close to each other.
When the column is close to the property line and the isolated footing Fig.3: Combined Footing
would cross the property line or become eccentric. Source: https://civiltoday.com
Dimensions of one side of the footing are restricted to some lower value.
4. Cantilever or Strap Footing
Strap footings are similar to combined footings. The reasons for considering
or choosing strap footing are identical to the combined one.
In strap footing, the foundation under the columns is built individually and
connected by a strap beam. Generally, when the edge of the footing cannot be
extended beyond the property line, the exterior footing is connected by a strap beam
with the interior footing.
The individual footing areas of the columns are so arranged that the C.G of
the combined loads of the two columns passes through the C.G of the two footing
areas. Once this criterion is achieved, the pressure distribution below each
individual footing will be uniform. Fig.4: Cantilever or Strap Footing
Source: https://civiltoday.com
5. Raft or Mat Foundation
Raft or Mat foundations are used where other shallow or pile
foundations are not suitable. It is also recommended in situations where the
bearing capacity of the soil is inadequate, the load of the structure is to be
distributed over a large area, or the structure is subjected continuously to
shocks or jerks.
Raft foundations are economic when:
The soil is weak and the load has to be spread over a large area.
The structure includes a basement.
Columns are closely placed.
Fig.5: Raft or Mat Foundation
Other kinds of foundations are not feasible.
Source: https://civiltoday.com
Differential settlement is to be prevented.
Types of Deep Foundation/Footing
1. Pile Foundation
Pile is a common type of deep foundation. They are used to reduce cost, and when as per soil
condition considerations, it is desirable to transmit loads to soil strata that are beyond the reach of shallow
foundations.
The followings are the types of pile foundations.
1. Based on Function or Use
Sheet Piles
Load Bearing Piles
End Bearing Piles
Friction Piles
Soil Compactor Piles
2. Based on Materials and Construction Method
Timber Piles
Concrete Piles Fig.6: Pile Foundation
Source: https://civiltoday.com
Steel Piles
Composite Piles
2. Pier Foundation
Pier is an underground structure that transmits a more massive load, which cannot be carried by
shallow foundations. It is usually shallower than piles. The pier foundation is generally utilized in multi-
story structures. Since the base region is determined by the plan strategy for the regular establishment, the
single pier load test is wiped out. Along these lines, it is increasingly well-known under tight conditions.
Pier foundation is a cylindrical structural member that transfers
heavy load from the superstructure to the soil by end bearing. Unlike
piles, it can only transfer load by bearing and by not skin friction.
Pier Foundation is economic when:
Sound rock strata lie under a decomposed rock layer at the
top.
The topsoil is stiff clay that resists driving the bearing pile.
When a heavy load is to be transferred to the soil.
Fig. 7: Pier Foundation
Source: https://civiltoday.com
3. Caisson Foundation
Caisson foundation is a watertight retaining structure used as a bridge pier, construction of the dam,
etc. It is generally used in structures that require a foundation beneath a river or similar water bodies. The
reason for choosing the caisson is that it can be floated to the desired location and then sunk into place.
A caisson foundation is a ready-made hollow cylinder depressed into the soil up to the desired level
and then filled with concrete, which ultimately converts to a foundation. It is mostly used as bridge piers.
Caissons are sensitive to construction procedures and lack construction expertise.
There are several types of caisson foundations.
1. Box Caissons.
2. Floating Caissons.
3. Pneumatic Caissons.
4. Open Caissons.
5. Sheeted Caissons.
6. Excavated Caissons.
Caisson foundations are economic when:
Fig.8: Caisson Foundation
The pile cap requirement is to be minimized. Source: https://civiltoday.com
Noise and vibration needed to be reduced.
It has to be placed beneath water bodies.
Highly lateral and axial loading capacity is required.
