Modification and Modeling of Experiments with Bi-directional Loading on Reinforced Concrete Columns

Abstract

Capacity evaluation of bi-directionally loaded column is important not only for the performance-based seismic design of structures but also for the estimation of structural damage. In this paper, an experimental study has been carried out on full-scale columns with different axial stress ratios, followed by the development of an analytical model to predict the lateral load response of the column under bi-directional loading after taking care of the effect of the functional interactions between the two loading actuators and the column specimen. These interactions, if not taken into account, result in apparent underestimation of ultimate strength and overestimation of maximum displacement capacity of the test specimen, thereby demanding unnecessary changes in model parameters for the purpose of calibration. It is also found that the analytical model accounting for the aforementioned functional interactions leads to a more realistic and different dynamic structural response from that obtained using the analytical model ignoring the interactions.