Experimental and Analytical Investigations of Seismic Performance of Cantilever Reinforced Concrete Columns Under Varying Transverse and Axial Loads

Abstract

To assess the parameters influencing the seismic performance of plastic hinge regions in Reinforced Concrete (RC) columns, eight large-scale and eight small-scale cantilevered RC columns were tested under various vertical and horizontal loading patterns. Three different axial loads were imposed on the columns: a constant moderate load, a constant high load, and a varying axial load. In addition to this, there were three lateral loading patterns: uni-directional, square, and circular. The high axial load and bi-directional loading had a significant influence on the envelope curves as well as on the damage progress. The observed damage to large-scale columns was much more severe than that observed in the small-scale columns. The equivalent viscous damping for specimens under varying axial load was between the damping of the specimens under moderate to high axial load. An increase in the number of cycles caused a rapid degradation of the envelope curve of the load-displacement history. However, no significant effect was observed on the maximum lateral load carrying capacity, peak load. Analytical FEM results such as load-displacement, moment-curvature and axial strain shortening-curvature relations, closely matched the experimental results. © 2005, Architectural Institute of Japan. All rights reserved.