Experimental and Numerical Evaluation of Strength and Ductility of Regular and Cross Spirally Circular Reinforced Concrete Columns under Eccentric Loading

This research investigates the behavior of reinforced concrete columns subjected to eccentric loading (combination of axial loading and bending moment) with experimental and numerical methods. The columns are reinforced and confined with regular spiral and cross spiral to enhance their strength and ductility. Fourteen R/C circular columns subjected to different load eccentricity with two different grades of spirals steel are experimentally tested. The force, axial and lateral displacement and concrete strains in different locations are measured during the testing. The columns are 2000 mm long and 250 mm diameter. The results show that regular spirally circular columns have more strength as compared with the cross spirally circular columns but the ductility of cross spirally columns has increased with respect to the regular ones. It was also observed that the use of higher yield strength for transverse reinforcement caused considerable increased ductility with respect to lower yield strength reinforcements.