Behavior of seawater sea sand concrete-filled bimetallic tube stub columns subjected to axial compression

The mechanical behavior of seawater sea sand concrete (SSC)-filled bimetallic tube (SSCFBT) stub columns under monotonic axial compression is systematically investigated through a combination of experimental testing and finite element analysis (FEA). The main test parameters considered included the strength of SSC and the crosssectional diameter of the bimetallic tube. The research findings reveal that the SSCFBT columns exhibit a ductile failure process under monotonic compression, demonstrating a favorable load-carrying capacity. The failure mode is predominantly characterized by local buckling in the bimetallic tube, with a separation phenomenon observed at the tube bulge. The overall behavior of SSCFBT members parallels that of conventional concretefilled steel tubes, and the corresponding axial compressive strength is found to be positively correlated with the strength of the SSC. The study concludes with the verification of available formulas to predict the compressive strength of SSCFBT members, thereby assessing the feasibility of this composite member for practical engineering applications.