Piles foundations are used to transfer
the weight of the structure below the ground from the surface of the ground.
Two main components of the foundation are pile and pile caps. Piles are long
and slender structure that is buried deep in the ground to take the weight deep
down in the ground. The piles are often touching the rock or solid ground,
going beyond the shallow depth of the soil. The material of the pile and load
transferring depends on the type of the soil.
Classification of the piles can be done
on the load bearing characters and material used in the construction of the
piles.
Point bearing piles are Bored piling contractors used to
transfer the load of the structure to the deep part of the soil. The carrying capacity
of these piles is derived from the resistance, which they get from the soil at
the toe of the pile. The pile behaves like an ordinary pile and it is designed
as such. The pile will never buckle under pressure even in weak soil. The depth to which pile is inserted depends
on the soil analyses, done by engineers before start of the construction.
Friction piles derive their carrying
strength from the friction of the soil, which is in contact with the shaft of
the pile. Cohesion piles transfer most of the weight of the structure by skin friction.
The cohesion piles are inserted in groups close to each other. This process
reduces the porosity and compressibility of the soil in and around. These piles
area also called compaction piles. When the piles in inserted in the ground,
the soil becomes molded and losses some of its strength, but it again regains
that strength after some three to five months.
Classification
of piles based on material used in construction –
Timber piles are used in areas where
timber is widely available. The timber used for piling has to be of good
quality and free from insects. The timber pile is place below the ground water
level to protect it from decay and putrefaction.
Concrete piles can be under reamed pile foundation
pre cast concrete and pre fabricated concrete piles. These are made in square, circular,
triangular or rectangle shapes. These piles can be connected to produce the
length required. The need for reinforcement is needed to enable the pile to
withstand both driving and handing stress. Pre stressed piles are becoming more popular
as they require less reinforcement.
