Influence of various impact scenarios on the dynamic performance of concrete beam-column joints

Abstract

This study investigated dynamic performances of concrete beam-column joints under various impact loading scenarios including impact contact condition (i.e., impact directly or via an interlayer), impact location, and impact loading pattern (i.e., concentrated or distributed loads). The influence of impact contact conditions was experimentally studied by a pendulum impact testing system. The test results showed that the softer contact by using a rubber pad led to an impact force profile with a less prominent force peak but resulted in more flexural concrete cracks on the beam. Furthermore, the finite element models of beam-column joints under impact were developed and verified by the test results. Based on the calibrated numerical models, the effects of impact location and impact loading pattern on the dynamic performances of joints were investigated. It was found that the specimens exhibited more flexural-governed cracks as the impact location moved away from the joint area. In addition, the distributed impact loading pattern resulting from an impactor with a wider contact area caused higher impact force, larger displacement response of beam, and severer damage at joint area than those generated by the concentrated impact loading pattern of the same kinetic energy, indicating the distributed impact loading is a more dangerous impact scenario to the safety of beam-column joints.