Impact resistance performance and simplified calculation method of web-opened steel beams under impact loads

Abstract

To investigate the impact resistance performance of web-opened steel beams (WOSBs) under impact loads, 26 specimens of WOSBs were designed and performed the falling-hammer impact tests, focusing on the impact energy, inter-opening space, opening height, and steel strength. The test results showed that the local deformations of WOSBs exhibited Vierendeel shear deformation and out-of-plane lateral buckling of the web under impact loads. At the initial impact stage, the time delay effect between the peak impact force and the peak reaction force accounts for approximately 9.77% of the total impact duration. The increase in impact energy and opening height had an adverse effect on the impact resistance performance of WOSBs. That is, as the impact energy (or opening height) increases, the average residual displacements for H1, H2, and H3 (H1, H2, and H3 represent WOSBs corresponding to three different steel materials: Q235, Q550, and Q690, respectively) increase by approximately 23.85% (18.07%), 34.05% (24.00%), and 33.20% (37.20%), respectively. The average impact efficiencies for H1, H2, and H3 are 77.38%, 72.90%, and 72.74%, respectively. This indicates that the unique geometric characteristics of WOSBs can be effectively utilized in the design of energy-absorbing structures. In conjunction with current steel structure design standards, a calculation method for the impact resistance performance of WOSBs was proposed by introducing the dynamic amplification factor and energy absorption ratio.