Confident Group

Piling for Confident Atria III, Project, Kochi

Introduction

It is well known that any building, house or structure to be well built, must have a very strong foundation and underground structural base that supports the building.

“Piling” is a technique used by civil engineers to set a deep foundation for buildings.

By driving and embedding piles of concrete or steel deep into the soil, the engineers provide a strong support to the building at the base level. Factors like size, capacity and scope of the project, the condition of the soil immediately beneath the ground and the space required for rigging all need to be taken into consideration. For this “test-piling” is carried out and soil analysis is also done to determine whether the soil is rocky, sandy or loamy etc.

A deep foundation is used to transfer the load of the structure to the deeper, stronger layer of soil which has a higher load bearing capacity and can take the load thus anchoring the structure effectively. “Piles” made of concrete or steel – precast concrete are driven into the ground, thereby making a solid foundation for supporting the structural load.

Stages of Piling Activity


1.	Soil testing or investigation is carried out to determine the depth of the hard soil strata at the building site. Based on the results the depth of cement concrete piles is determined. The high-rise rests on 200 to 300 cement concrete piles driven to a depth of almost 30 meters.

2.	Boring is the first step in piling. Heavy weight chisels weighing 1.6 tons and a motor driven winch is used for boring. The soil is loosened by using the chisel and the loose soil is continuously flushed out by using liquid slurry of a chemical called Bentonite. Bentonite slurry has a unique property of flushing out the loose soil while providing a bonding strength for the sides of the boring cavity. The boring is stopped after a depth of 27.2 meters after testing the strength of the hardness of the surface at the bottom layer.

3.	Steel reinforcement weighing roughly 750 meters is inserted in the bored cavity. This will provide each pile with the necessary tensile strength.

4.	To prevent the walls of the bored well from caving in, the cavity is continuously flushed with Betnovate slurry for almost one hour.

5.	After the flushing concrete mix is pumped into the cavity. About 21 cubic meters of concrete is used for the process .Factory fresh cement mixed with first quality aggregates are used to prepare the concrete, in a state of the art automated batching plant. Samples of the concrete are collected for verifying strength and to see that it conforms to the desired specifications.

6.	After curing the RCC pile for 28 days the top soil around the pile is excavated and the pile tip is exposed. The excess length of the pile is accurately marked and manually chipped off. The slow manual process is preferred as against mechanical chipping, as this could damage the concrete pile below the surface. Piling is a slow but very crucial activity in a high-rise building construction. Extra care and extreme precaution is required to ensure high quality. Therefore it normally takes 4- 5 months for completion.

Conclusion

In Atria III, Pukkattupady, Cochin test pile has already been concluded. The piling activity will start in mid September 08 and concluded by 15th March 09.