Experimental Investigations on Reinforcement Configurations in RCC Micropiles

Micropiles are piles of short length and small cross sectional area. The non availability of equipment, high cost of installation of metallic piles and their susceptibility to corrosion have prevented the wide application of micropiling technique. Studies on driven reinforced cement concrete (R.C.C.) micropiles are discussed herein. The investigation was aimed at finding the suitable reinforcement configuration for such R.C.C. driven micropiles. Micropiles of different diameters and lengths were tested. Reinforcement configurations were chosen giving attention to the ease of casting the piles. The selection of concrete mix required several casting trials. Axial load tests and bending tests on laboratory model micropiles were undertaken. Crushing failure was noticed at the ends during axial load tests. Specially designed end sleeves are found to be very useful to prevent the failure of the micropiles at the ends. The use of end sleeves was also found to increase the axial load carrying capacity of the micropiles.