Performance Comparison of Circular and Square RC Columns under Monotonic Loading Conditions

Abstract

Current flexural and shear design methods for reinforced concrete members are mainly based upon the rectangular cross-sectional shape. A simplified new approach for designing circular cross sectional Reinforced Concrete (RC) members might be to convert them to equivalent area, square shapes. An experimental study was performed on reinforced concrete circular cross sections and equivalent area, rectangular cross sectional members. The RC members were tested under non linear monotonic loading conditions, under both flexural and shear controlled conditions. Furthermore, the 3D FEM package COM3D was used to simulate the nonlinear performance of circular and its equivalent area, square members. Experimental and analytical results show that the circular RC members and its equivalent square have similar nonlinear performance (load-deflection behavior) in both flexural and shear controlled failure conditions. A good agreement was found in nonlinear performance of main design criteria; initial stiffness, flexural capacity, and shear capacity of both types. Based upon these results, the proposed approach can be considered satisfactory.