Function of the piles and its classification

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.