Pile foundation at Arail Ghat

INTRODUCTION

A pile foundation is usually provided when the soil at shallow depth is poorin order to transmit the load safely, the depth of foundation has to increaseda suitable soil stratum is met. In view of increased depth, such foundationscalled deep foundations . Piles, piers and wells are examples offoundations. Different types of pile foundations are discussed in the followingsections.

Types of Piles

Piles have been classified using different criteria. Some of these criteria are:On the basis of method of construction

1)Timber2)Steel3)Concrete4)Composite

Timber PilesSteel Piles

Composite Piles

On the basis of Cross-section:

1)Circular2)Square3)Hexagonal4)I- section5)H-section6)Pipe(hollow)

On the basis of shape:

1)Cylindrical2)Tapered3)Underreamed

Tapered Piles

Underreamed Piles

On the basis of load transfer:

1)Bearing2)Friction3)Tension

Tension Piles

On the method of forming:

1)Precast2)Prestressed3)Cast in situ

Precast Piles

Driven Prestressed Piles

On the basis of installation:

1)Driven

2)Bored3)Vibrated4)Jetted

Driven Piles

Bored Piles

Vibrated Piles

Jetted piles

However it is realised that the best way of classifying the pile is on the basis of the effect of installation of pile on the soil. Based on this creterion, piles can be considered into two main classses:

1)Displacement Piles-During installation of piles, large amount of soil is displaced laterally and upwards.

2)Non Displacement Piles-Those piles whose installation does not lead to any displacement of soil. A void is formed in the soil by boring or excavation and is then filled with concrete.

Arail Ghat specifications:

1)Construction site dimension-300m*165m.2)Type of Piles: On the basis of matrial of construction-Concrete

On the basis of cross section-CircularOn the basis of shape-UnderreamedOn the basis of mode of load transfer-FrictionOn the basis of method of forming-Cast in situOn the basis of method of installation-Bored

3)Pile specifications:-Diameter of piles=200mm-Length of piles=6000mm-Pile cap=200mm-Longitudinal Reinforcement=12 mm Fe 500-Shear stirrups of 8mm Fe 500 @ spacing of 200mm-OPC Grade 43 Cement-M25 Concrete -1:1:2 Mix design-40:60 ratio of coarse aggregates used of 10mm and 20mm respectively.-Cover of 50mm-Hand operated Auger is used for boring