Experimental and numerical studies on square steel-reinforced concrete-filled steel tubular (SRCFST) members subjected to lateral impact

Steel-reinforced concrete-filled steel tubular (SRCFST) structures were proposed in recent years and have been employed in engineering practices. To date, the existing studies mainly focused on the behaviours of SRCFST structural members under static or seismic load. Only very limited studies of the SRCFST structural members subjected to impact load, which might cause severe damage and even structural collapse, can be found in literature. In this study, experimental and numerical studies on square SRCFST specimens under lateral impact load are conducted. A total of eighteen square SRCFST specimens are fabricated and tested via a drop hammer impact device. Various parameters (i.e. impact velocity, boundary condition, impact direction, cross-section of steel profile and axial load level) are considered to evaluate their effects on impact responses of square SRCFST members. The damage modes, impact forces, mid-span displacement responses and energy absorption capacities of the tested specimens are extracted from testing data and analysed. Furthermore, by using the software ABAQUS, numerical model is established and validated with the testing results. With the validated numerical models, the damage evolution, sectional stress and energy distribution of the structure with different parameters and impacting scenarios are evaluated. The impact behaviours of square SRCFST and concrete-filled steel tubular (CFST) members are also compared and discussed.