SHRI RAMSWAROOP MEMORIAL UNIVERSITY

LUCKNOW – DEVA ROAD, UTTAR PRADESH

ARCHITECTURAL
STRUCTURES - V
BAR5003

TOPIC – FOUNDATION AND ITS TYPES

SUBMITTED TO:
SUBMITTED BY:
MR. KAMAL KUMAR SACHIN KUMAR PATEL
B. ARCH II ST YEAR IIND SEM
201811101010002
SRMU
 INTRODUCTION
•  A structure essentially consists of two parts, namely the
super structure which is above the plinth level and
the substructure which is below the plinth level.
• Substructure is otherwise known as the foundation and
this forms the base for any structure.
• Generally about 30% of the total construction cost is
spent on the foundation.
• The soil on which the foundation rests is called the
“foundation soil”.
INTRODUCTION
 OBJECTIVES OF A FOUNDATION
A foundation is provided for the following purposes:
• To distribute the total load coming on the structure on a
larger area.
• To support the structures.
• To give enough stability to the structures against various
disturbing forces, such as wind and rain.
• To prepare a level surface for concreting and masonry work.
 FACTORS AFFECTING DESIGN OF
FOUNDATION
Following are the factors which affect the selection of
suitable foundations for building construction:
• Loads from building
• Type of soil
• Type of structures in neighbourhood
• Type of foundations
 LOADS FROM BUILDING
• The first factor considered is loads from building on the
foundation. This load is a combination of dead load and
imposed loads on the buildings. Other loads such as
wind loads, earthquake loads, snow loads etc. are also
considered based on location.
 TYPE OF SOILS
• Soil is a mixture of solid particles, moisture and air. Soil can be
of many types such as clayey soil or expansive soil, sandy soil or
loose soils etc. The soil near surface is called as top soil and
below a depth of 300mm is called as sub soil. Generally subsoil
is used as base for foundation for small buildings.
The soil investigation should be carried out for
following information:
• The nature and thickness of made-up ground/top soil above the
sub-soil
• The nature, thickness and stratum depth of sub-soil
• An assessment of allowable bearing pressure
• Groundwater levels, chemicals in the ground, etc.
• Existing structures or hazards in the ground.
 TYPE OF SOILS
• When the load is transferred from the structure to soil through
foundations, the soil tends to consolidate and settlement of
foundation occurs. This consolidation process can be quick in
case of non-cohesive soils such as sands and can even take years
for other soils.
• The settlement of foundation causes cracks in building walls,
beams, slabs etc. and building can even fail in case of large
settlement.
 TYPE OF STRUCTURE IN
NEIGHBORHOOD
• The selection of foundation for building construction can also
be done based on the type of foundation selected for the
buildings in the neighbouring buildings for the same types.
Based on the success or failure of foundations for such
buildings, decision can be taken for the selection of
foundation.

TYPES OF FOUNDATIONS
• Types of foundation such as isolated foundations, combined
footings, pile foundations and raft or mat foundations etc.
based on the type of soils and loads from the buildings can be
selected based on suitability and requirement.
 TYPES OF FOUNDATION
SHALLOW FOUNDATION
• Depth of foundation is less than or equal to its width.
• Shallow foundations are commonly used as they are the most economical
foundation system and are relatively easy to construct.
The different types of shallow foundations are:
• Spread or Isolated Footing;
• Strip Foundation;
• Mat or Raft Foundation;
• Combined Foundation.
 TYPES OF FOUNDATION
ISOLATED FOOTING
• Isolated footings (also known as Pad or Spread footings) are commonly used for
shallow foundations in order to carry and spread concentrated loads, caused for
example by columns or pillars.
• Isolated footings 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.
Mainly three are types
• Pad footing Or Simple Spread footing
• Stepped Spread footing
• Sloped spread footing
The shape of Isolated footings
• Square
• Rectangular
• Circular
 TYPES OF FOUNDATION
• STRIP FOUNDATION
• Strip foundations consist of a continuous strip, usually of concrete,
formed centrally under load bearing walls. 
• This continuous strip serves as a level base on which the wall is built and
is of such a width as is necessary to spread the load on the foundations
to an area of subsoil capable of supporting the load without undue
compaction.
• Strip foundations are used where the soil is of good bearing capacity.
• The depth of a strip foundation must be equal to or greater than the
overall width of the wall. The width of the foundation must be three
times the width of the supported wall.
 TYPES OF FOUNDATION
MAT OR RAFT FOUNDATION
• A raft foundation, also called a mat foundation, is essentially a continuous
slab resting on the soil that extends over the entire footprint of the building,
thereby supporting the building and transferring its weight to the ground. 
• A raft foundation is often used when the soil is weak, as it distributes the
weight of the building over the entire area of the building, and not over
smaller zones (like individual footings) or at individual points (like 
pile foundations). This reduces the stress on the soil.
• A raft foundation is also very good for basements.
 TYPES OF FOUNDATION
COMBINED FOOTING
• A Combined footing supports two or more columns in a row. The Combined
footings can be rectangular in shape if both the cumin carry equal loads, or can
be trapezoidal if there are space limitations and they carry unequal loads.
There are two types
• Rectangular combined footing
• Trapezoidal combined footing
Combined footings condition
• When two columns are close together, causing overlap of adjacent isolated
footings.
• Where soil bearing capacity is low, causing overlap of adjacent isolated footings.
• The proximity of building a line or existing building or sewer, adjacent to a
building column.
• When the bearing capacity of the soil is low due to which the dimensions to be
provided for each of the isolated footings come out to be high and hence they
overlap, the combined footing is provided.
TYPES OF FOUNDATION
 TYPES OF FOUNDATION
DEEP FOUNDATION
• If the depth of footing greater or equal to the Width of footing, it is known as
the deep Foundation. 
• Deep Foundation is used Where the bearing capacity of the soil is very low. The
load coming from the superstructure is further transmitted vertically to the soil.
TYPES OF DEEP FOUNDATION
• Pile Foundation
• Pier Foundation
• Well Foundation
 TYPES OF FOUNDATION
• PILE FOUNDATION
• Pile Foundation is used when the soil below is of the least uality.
• in simple words as “Piling is like piercing screw in to the land, by digging a
hole and inserting the materials”.
• Essentially, piling is a process where long structural members (typically
steel or concrete with reinforcement steel) are driven deep into the soil.
• This ensures an even distribution of the building loads over a large surface
area. For multi-storeyed residential buildings in areas with loose soil like
dried-up water-bodies, sea shore,  river-banks etc, piling is essential.
THANK YOU