Home | | Construction Techniques and Practices | Foundation : Functions And Types

Chapter: Civil : Construction Techniques, Equipment And Practices : Construction Practices

Foundation : Functions And Types

The foundation is he lower portion of the building, usually located below the ground level, which transmit the load of super structure to sub Soil .

Foundation : Functions  And Types

 

 

The foundation is he lower portion of the building, usually located below the ground level, which transmit the load of super structure to sub Soil . 

 

Functions of foundation


Reduction of load intensity

        Even distribution of load

 

        Provision of level surface

      Lateral stability

 

        Safety against undermining

        Protection against soil movements

 

Types of foundation

 

Shallow foundation

Deep foundation

 

1.     Shallow foundation

 

If the depth of foundation is less than or equal to width of foundation it is called as shallow foundation

 

Types of shallow foundation

 

Spread footing

 

Combined footing

 

Strap footing

 

Mat foundation

 

Spread footing

 

Spread footing is those which spread the super imposed load to of a wall or column over the large area

 

Spread footing support either a column or a wall

 

It has the following types

 

Single footing

 

Stepped footing

 

Sloped footing

 

Wall footing with out step

 

Stepped footing for wall

 

Grillage foundation


 

 

 

 


 

 

Combined footing

 

A spread footing which supports two are more columnsis termed as combined footing It has the following types

 

Rectangular combined footing

 

Trapezoidal combined footing

 

Combined column wall footing

 

Trapezoidal footing

 

If the independent footings of two columns are connected by a beam it is called as strap footing

 

A strap footing may be used where the distance between the columns is so great that a combined trapezoidal footing becomes quite narrow

 

The strap beam does not remains in contact with soil and thus does not transfer any pressure to the soil

 

2 Mat foundation

 

A raft or mat is a combined footing that covers the entire beneath a structure and supports all walls and columns. It is used when the allowable soil pressure is low are the building loads are heavy. It is used to reduce the settlement above highly compressible soil

 

Rafts may divided into three types

 

o Solid slab system

o Beam slab system

o Cellular system

 

Deep foundation

 

If the depth of foundation is equal to or more than the width of the foundation is called deep foundation

 

Types

 

Deep strip rectangular or square footing

 

Pile foundation

 

Pier foundation or drilled caisson foundation

 

Well foundation or caissons

 

Deep strip footing

 

 

Whenever the depth of strip footing is more than the width it is called as deep strip footing


 

 

 

 

Pile foundation

 

it is a type of deep foundation in which the loads are taken to a low level by means of vertical members which may be timber or concrete or steel

 

Types of pile foundation

 

End bearing pile

 

Friction pile

 

Combined end bearing and friction pile

Compaction pile

 

End bearing piles

 

End bearing piles are used to transfer load through water or soft soil to a suitable bearing stratum

 

Such piles are used to carry heavy loads to hard strata

 

Multi storied buildings are invariably founded on end bearing piles, so that the settlements are minimized

 

Friction piles

 

Friction piles are used to transfer loads to a depth of a friction load carrying material by means of skin friction along the length of the pile

 

These piles mostly used in granular soil

 

Combined end bearing and friction pile

 

These are the piles which transfer the super imposed load both through side friction as well as end bearing

 

Such piles are more common, especially the end bearing piles are passed through granular soil

 

Compaction piles

 

These piles are used o compact loose soil thus increasing there bearing capacity

 

The pile tube driven to compact the soil is gradually taken out and sand is filled in its place thus forming the sand pile

 

Pier foundation

 

A pier foundation consist of a cylindrical column of large diameter to support transfer large super imposed loads to the firm strata below

 

 Generally pier foundation is shallower in depth than the pile foundation


 

 

 

 

It has two types

 

Masonry

concrete pier

 

Drilled caissons

 

Well foundation or caissons are box like structures -circular or rectangular which are sunk from the surface of either land or water to the desired depth

 

Caisson foundations are used for major foundation work such as

 

Bridge pier and abutments in river

 

Wharves and quay walls docks

 

Large water front structures such as pump houses, subjected to heavy vertical and horizontal loads

 

Well foundations are caissons are hollow from inside, which may filled withstand and are plugged at the bottom, the load is transferred to the perimeter wall called as steining


Study Material, Lecturing Notes, Assignment, Reference, Wiki description explanation, brief detail
Civil : Construction Techniques, Equipment And Practices : Construction Practices : Foundation : Functions And Types |


Privacy Policy, Terms and Conditions, DMCA Policy and Compliant

Copyright © 2018-2023 BrainKart.com; All Rights Reserved. Developed by Therithal info, Chennai.