Seismic Performance of Circular Concrete Columns Reinforced by PC Strands

This paper has proposed a new and simple approach to making drift-hardening circular concrete columns with reduced residual deformation by utilizing non-prestressing PC strands as longitudinal rebars. In order to verify the effectiveness of this method, quasi-static tests on five circular concrete columns were carried out. Four columns were reinforced by PC strands and the other one was reinforced by normal-strength rebars. The experimental variables included the axial load ratio, the shear span ratio, and the confinement method within the potential plastic hinge region. The test results show that the columns utilizing PC strands possess a drift-hardening capability up to 5% drift and the residual drifts are significantly reduced if the PC strands are well anchored at both ends. In addition, it is indicated that partial confinement by bolted steel tube (BST) can further enhance the lateral drift-hardening stiffness and reduce the residual deformation. Furthermore, a new nonlinear analysis method considering the bond-slip effect is introduced to evaluate the lateral response of the proposed columns. Comparisons between the experimental and analytical results indicate that the presented nonlinear analysis method can predict the lateral response of the proposed columns very well.