Ticker

6/recent/ticker-posts

Header Ads Widget

Types of Foundation in Civil Engineering Details Discussion.

Foundation in Civil Engineering

What is Foundation in Civil Engineering:

Lowest part of any kind of structural frames, which is stay into the soil, that is called the foundation. In other words, lowest part of structural frame into the soil is called foundation.

 It has been works as like the base of structure. So it is also called the base of structure.

In different words, structures self weight and above other self weight has been transferred into the hardest layer of soil which is made by concrete block, pile, raft, mat, grilles' etc  is called the foundation.

The total weight of structural frame has been laying on the hardest layer of soil. So for this reason, hardest layer of soil has been made with very carefully. 


What is Foundation Engineering:

Foundation, types of foundation, character analysis, design and others part descriptions has been given in which special division, that is called foundation engineering.

The most important division of civil engineering is the foundation engineering. Without foundation of civil engineering, I say that as like as prescription without Doctor.


Foundation Engineering Study Steps:

Building or any other engineering structure, footing, foundation wall, pile foundation etc design, capacity of building, re-works, supervision has been discuss in foundation engineering subject.

Generally, foundation carry the total weight of structures. But actually foundation is for spread out total weight of structure into the soil. 

So, the main works of foundation is spread out dead load, live load, wind load, earthquake load and others type load into the soil.


Main Purpose of Foundation:

(1) Load Intensity Reduction:

Foundation decrease the intensity of load. To spread weight of structure over a larger area, so that the foundation floor can avoid overloading. The load imposed on the foundation surface shall in no way exceed the bearing capacity of foundation soil.

(2)  Balanced Distribution of Load:

The foundation work is to spread the unequal load of the superstructure even the ground. That is, the load is evenly distributed to the solid layer of soil to prevent uneven seating of the structure.

(3) Provide a Flat Surface:

Provides a hard and flat surface for the structure. That is to get a flat surface to facilitate the construction work of the structure.

(4) Durability:

To hold the superstructure as an anchor i.e to prevent the slip and invert to gain the stability of the structure, prevent the horizontal force.

(5) Provide Security:

The flood waters provide protection to the structure from the hands of the animals living in the mud holes.

(6) Prevent Soil Erosion:

The foundation prevents the superstructure from being damaged due to compression or expansion of the soil or due to moisture.


Requirements of a satisfactory Foundation:

The engineering structure is located on the ground because it has a foundation. The requirements for a good foundation are as follows-

1. The foundation should be constructed in such a way that all the weight of the structure easily carries dead load and compressed load and transferred it to the foundation ground.

2. The foundation should be cut the required depth so that the structure is not damaged due to increase or contraction of the soil volume of the foundation.

3. The foundation must be laid in such a way that there is no unforeseen loss in the future.

4. The foundation should be strong enough to reduce wear when the load applied from above is not evenly distributed.



Classification of Foundation:

The foundation has been divided into two type.

(1) Shallow Foundation
(2) Deep Foundation


Shallow Foundation:

When the lowest part of superstructure is placed at a shallow depth inside the soil, It is called a shallow foundation. Although the depth of the foundation is greater than the width, if the foundation is constructed by digging freely, it is called shallow foundation.

According to design of structure, shallow foundation are 4 Types.

1. Spread Footing

2. Strap Footing

3. Combined Footing

4. Mat or Raft Foundation


Spread Footing:

The footing that is constructed to extend the base of the structure step by step and spread it over a larger area of the structure that is called spread footing. 

This type of footing has been spread step by step so that it can bear a huge load in the larger area. 

Foundation in Civil Engineering

That is, according to the bearing capacity of soil , foundation will be increase step by step. Spread footing provide support to the column or wall. 

There have different footing for every column or wall. Although they are considered separately according to the design and construction method.

Spread footing can be square, rectangular, circular and others type for column.


Strap Footing:

Strap footing is that footing which are continuous into the footing or can be continue with strap beam in a foundation. 
The picture is given related with combined footing.

Types of Foundation

Mat or Raft Footing:

When a combined footing covers all the lower areas of the structure and supports the main wall and column of the structure together  that is called mat or raft foundation. 

Foundation

Mat or raft foundation which give the support all wall and column together. Filled soil, soft soil, reservoir area, where soil bearing capacity is low then provide there raft or mat foundation. 

Raft or mat foundation has been provide for below reason- 

1. Increase the area of foundation for the low bearing capacity of soil.

2. Provide mat or raft foundation for preventing the compression of liquid hydrostatic materials.

3. Prevent lose soil pocket provide raft or mat foundation.


Deep Foundation:

When the lowest part of superstructure is placed at a long depth inside the soil, It is called a deep foundation. Although the depth of the foundation is more larger than the width, it is called deep foundation.

When a hardest layer is not found for the foundation in the soil then deep foundation has been constructed. Beside this, for long lasting of building there have been provide deep foundation.

Deep foundation are three types.

1. Pile Foundation

2. Caisson or well Foundation

3. Cofferdam


Pile Foundation:

Lay the foundation if the depth of required bearing level is too high or the surface is too sleep if that foundation is to be built is called pile foundation.

Pile has been laying by blowing into the soil and fill up by the concrete. The main works of pile is transferred the structure load into the hardest layer of soil.


Caisson:

Structures that are built to lay the necessary depth under the ground or under water that is called caisson. This is built by wood, steel, concrete, RCC etc. Caisson need for these below reason-

1) For flowing the water.
2) To make confined space.
3) To reach the bridge pier or heavy loaded column into heavy loaded layer.

Generally to make these structure, caisson are use-

1. River Abetment
2. Bridge Pier
3. Coastal largest Structure
4. Coastal guard structure


Cofferdam:

Temporary foundation which is the foundation to prevent water from entering during construction work in river, lake etc then it is called cofferdam. It depends depth of water, soil condition, water layer up down, construction materials adequacy.


Factors Governing the depth of Foundation: 

(1) Depth of Top Soil
(2) Snowfall
(3) Bearing capacity of soil

(4) Adjacent footings and property lines
(5) Sloping Ground
(6) Water Table

(7) Scour Depth
(8) Underground defects
(9) Root Holes

(10) Minimum Depth

Thanks to All for Reading.

Post a Comment

2 Comments