Confident Group

Piling for Confident Althena Trivandrum Project

Principle of Piling Foundation

The purpose of any building foundation is to provide a firm support for the structure, so that the structure load is transmitted to the ground without exceeding the safe bearing capacity of the soil. For large structures, it may be necessary to reach greater depths to locate strata which has adequate bearing capacity. DMC piling is a very effective technique used world-over for providing sturdy support for high-rise buildings, and at Confident Althena Trivandrum, we have successfully completed the DMC piling for the Orchid Block.

The soil investigation for our project site at Menamkulam was carried out by the an expert team from the Civil Engineering faculty of College of Engineering Trivandrum. The soil test results revealed hard soil strata at approximately 25 meters deep. Based on the soil test results, the pile design was carried out by the well known structural consultant Mr. Asoka Rao of Structures Consultancy, Bangalore who has completed over 100 High Rise Projects. Based on most optimal design with high safety features, your dream home will be resting on 268 reinforced cement concrete piles, each reaching to a depth of 27.2 meters to touch a very hard earth strata—literally resting your home on a solid foundation!

The photographs below will give you a glimpse of this very important activity, a crucial phase of high-rise building construction.

Photo 1- Boring

First step in Piling. This is done with heavy weight chisels ( 1.6 tons weight), and a motor-driven winch. The soil is loosened by the impacts of the chisel and it is flushed out continuously by Bentonite liquid slurry, which has a unique property of flushing out the loose soil while providing a bonding strength for the sides of the bore hole. The boring is stopped on reaching a depth of 27.2 meters, after confirming the hardness of the surface at bottom stratum(SPT test)

Photo 2- Inserting Steel Reinforcement

Steel reinforcement ( weighing approximately 750 kilograms for each pile) is inserted in the bore hole. This steel provides the pile with the necessary tensile strength.

Photo 3-Flushing

After boring is completed, the bore hole is gently flushed continuously for one hour. This is achieved by pumping Bentonite slurry with specific gravity of 1.12. This is a very important activity which will ensure proper bonding and strength for the side walls, to prevent caving.

Photo 4-Concreting

After flushing, concrete mix is pumped into the bore, thus completing the RCC piling activity. Approximately 21 cubic meters of concrete is used for each pile. Factory-fresh cement and first quality aggregates are used to prepare the concrete, in a state-of-the-art automated batching plant. Samples of concrete are collected for testing strength after curing, to verify conformance with the specifications.

Photo 5-Load Testing

Selected piles are load-tested by applying load up to twice its design load ie, a 150 Ton pile is tested by applying a load of 300 Tons. This is to ensure that the pile will safely carry the design load at all times, even under extreme conditions.

Photo 6-Escavation & Pile Chipping

After curing the RCC pile for 28 days, the top soil around the pile is escavated and pile tip exposed. The excess length of the pile is accurately marked and manually chipped off.Manual chipping is very slow, but is preferred because it is safer than mechanical chipping using rock drills.(chipping using rock drills could send vibrations down the pile, and may cause damage)

Conclusion

DMC piling is a slow but very crucial activity in a high-rise building construction. Extra care and precaution is required to ensure high quality piling normally it takes 4 to 5 months. Confident Althena Orchid we started piling in April 2008 and completed in July end as per the schedule in line with elaborate Confident Group’s Quality Systems and Standards.