Performance of HCFDST with corrugated steel tubes under lateral impact

Compared to the traditional hollow concrete-filled double-steel tube (HCFDST) with flat steel tubes (FSTs), HCFDST with corrugated steel tubes (CSTs) exhibits enhanced mechanical interlocking with core concrete, which could effectively prevent the formation of local debonding and buckling, thus improving its performance. Previous studies on HCFDST with CSTs mainly focused on its static performance, its dynamic responses under lateral impact are rarely investigated. In this study, a comprehensive numerical investigation is conducted to investigate the lateral impact behaviors of HCFDST with an outer CST by using LS-DYNA. The numerical model is first against experimental results, the influences of the key parameters related to the structural geometry and loading are then systematically investigated. Parametric analyses reveal that moderately increasing either hollow ratio or axial load ratio can enhance the impact resistance of HCFDST with an outer CST. Moreover, under a constant wave height-to-pitch ratio, increasing the wave pitch proves to be an effective approach for improving the impact resistance. Finally, simplified models are developed to predict the plateau force and maximum displacement, which shows excellent agreement with numerical data, thus providing practical tools for impact-resistant design of CST-based composite members.