Instrumented Pile Load Tests on Acip for a Real Estate Project in Kolkata- A Case Study-Paper

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The study reports an instrumented pile-load testing program for a proposed six-tower, 25-storey development near the Ganges in Kolkata. Because subsurface conditions were variable, five augered cast-in-place (ACIP) reinforced-concrete test piles were tested to verify design assumptions and measure load transfer and settlement.<br /><br />The piles ranged from 500 to 750 mm in diameter and 24 to 35 m in length. Each was fitted with vibrating-wire strain gauges at three depths and extensometers at two depths. Maintained static compression tests followed Indian Standard IS 2911 (Part 4, 2013). Strain measurements, combined with assumed concrete and steel properties, were used to estimate loads at instrumented levels and calculate shaft and toe resistance.<br /><br />At the maximum reported test loads, total shaft resistance ranged from approximately 2,735 to 6,075 kN. Mobilized toe resistance was small, accounting for about 0.53%–6.21% of applied pile-top load. The results indicated soft conditions at the pile toes, so the authors advised relying on toe resistance only after effective base cleaning and confirmation of firm bearing material.<br /><br />The study also highlights that pile shape and construction quality influence load-transfer interpretation. Bulges can create local bearing effects and increase the concrete cross-sectional area beyond the average assumed in design calculations. Accurate construction records are therefore important for interpreting instrumentation data reliably. Overall, the tests provided direct evidence of pile load–settlement behavior and showed that shaft resistance, rather than toe resistance, carried most of the applied load in the tested piles.

Keywords

instrumented pile-load testing

augured cast-in-place piles

Kolkata development

load transfer

settlement behavior

shaft resistance

toe resistance

vibrating-wire strain gauges

Indian Standard IS 2911

pile foundation design