Shear resistant performance of RC columns subjected to vertical near-fault velocity pulse-like earthquake actions

Single RC columns are used to investigate the influence of fault distance, vertical and horizontal acceleration spectral ratio, initial axial load ratio, fundamental period and shear span ratio on shear resistant behavior of RC columns. Eighteen-velocity pulse-like earthquake records divided into three-fault distance from Chi-Chi earthquake are used as excitations to execute nonlinear dynamic time history analysis. The results demonstrate that axial velocity pulse-like earthquake action has evident effects on the shear resistant performance of RC columns. Shear-resistant behavior factor decreases with the increase of spectral ratio, and medium initial axial load ratio and fault distance, shear span ratio and near fault distance (0~10 km) have coupling influence on the shear-resistant behavior of RC columns. Finally, nonlinear regression analysis of analytical data in the present study is carried out and empirical approach considering different effect of these factors is proposed.