Prediction of pre- and post-peak behavior of concrete-filled square steel tube columns under cyclic loads using fiber element method

The cyclic load-deformation relationships of columns in the post-peak region need to be investigated in the prevention of collapse of the buildings under earthquake excitation. This paper provides an efficient method of prediction of the pre- and post-peak hysteretic behavior of concrete-filled square steel tube columns subjected to a combination of constant axial load and cyclic lateral load. For this purpose, the simplified nonlinear fiber element method is used to obtain the uni-axial stress and strain relationship of materials in terms of the composite action between the steel tube and the concrete. The accuracy of the proposed computational technique is verified by comparing the results from this technique with existing experimental results, which are briefly reviewed in this paper.