Plastic Hinge Length of RC Columns under the Combined Effect of Near-Fault Vertical and Horizontal Ground Motions

Plastic hinges are an extension of the ductile design concept used in building seismically resistant structures. The formation of a plastic hinge in an RC column in regions that experience inelastic actions depends on the characteristics of the earthquakes as well as the column details. Recordings from recent earthquakes have proved that in the near-fault region of large earthquakes, the vertical component of the near-fault ground motion has exceeded the horizontal, and damage to the structures has been predominantly by these motions. Therefore, this paper focuses on near-fault ground motions that have been recorded within rather 20 km of the causative fault and 936 inelastic time-history analyses have been performed to predict the nonlinear behavior of RC columns subjected to combined effect of near-fault vertical and horizontal ground motions. The effects of some parameters are evaluated analytically by finite element methods and the results are compared with corresponding experimental data. Findings from this study provide a simple expression to estimate plastic hinge length of RC columns subjected to the combined effect of near-fault vertical and horizontal ground motions.