Concrete-filled double steel tubular beams under lateral impact

Concrete-filled steel tubular members have the merit of high strength and ductility, and are widely utilized in civil structures. However, corrosion of the steel tubes and live loads induced fatigue or coupling of these factors usually result in fractures generated on the steel tubes. The fractures may lead to a decrease in structural capacity and threaten structural safety, especially when the damaged members are subjected to impact loads such as vessel or vehicle impact. In this work, experiments are conducted firstly to examine the dynamic behavior of five damaged concrete-filled double steel tubular (CFDST) beams under lateral impact. The experimental results indicate that the deformation of the CFDST increases with the increase of initial damage severity under the same impact condition. The initial damage would change the failure modes of the CFDST beams. Based on the test results, the finite element models of the CFDST beams are validated. Then the parametric study is conducted to identify the influence of the thickness of steel tubes and initial fracture length on the displacement, impact force, and the increment in fracture length of CFDST beams.