Axial Compression Behaviour of Double Layered Confined Concrete Columns

Abstract

Informed knowledge suggested a need for increasing the confinement effectiveness of concrete in high rise buildings and mass transit systems to enable the structure with greater susceptibility to severe ground movements. Literature has further pointed at the possibility of double layered confinement and its potential for dissipating the significant amount of seismic energy. newlineThe researcher took up the task of testing it out through extensive lab experiments with the facilities available at the university at which the research work was registered and the facilities available at leading universities in the country for Civil Engineering research such as Indian Institute of Technology, Roorkie, Aligarh Muslim University, Aligarh and Integral University, Lucknow. 63 numbers of column specimens of the size (150x150x450) mm, some made of Normal and, other of High Strength Concrete confined with two layers of stirrups have been subjected to mechanical force at varying intensities in designated laboratories to test the axial compression behaviour. The column specimens were reinforced with 6 mm and 10 mm diameter bars of newline500 MPa grade as transverse and longitudinal reinforcements, respectively. The effects of various test variables on strength and deformability of confined concrete have been explored and evaluated. Two non-destructive testing methods, viz., Rebound Hammer Test and Ultrasonic Pulse Velocity Test have been applied to assess and validate the experimental results.Further, the mathematical models have been developed to capture the variation in axial compressive behaviour between the Normal and High Strength Concrete structures. The experimental results were compared with the simulation results to ensure the acceptability of the analytical models.The study has reinforced the positive perception about the contribution of double layered confinement in improving the strength and ductility of concrete columns in the process of resilience to calamities in the context of use of materials from Indian subcontinent .