Study on axial compression performance of double steel plate-concrete composite walls with stiffening ribs and tie plates

Local buckling has a significant effect on the mechanical performance of double steel plate-concrete (DSC) composite walls, which are composed of two faceplates, an infilled concrete core, and connectors between them. In this paper, a new type of DSC composite wall (SDSC) was proposed by incorporating stiffeners and tie plates welded on the internal surface to enhance the local stability of the faceplate. Eight SDSC specimens were designed to investigate the axial compression behavior of this new composite walls. During the tests, the buckling stress and the ultimate strength of these SDSC walls were measured, and the effects of the B/t ratio (i.e., the ratio of stud vertical spacing to faceplate thickness) and the stiffener spacing were analyzed as well. The results demonstrated that as the stiffeners and tie plates completely changed the faceplates's buckling mode, the buckling stress of the faceplates and the ultimate strength of SDSC walls were obviously increased. It was also concluded that, for the SDSC specimens with the same B/t ratio, decreasing the stiffener spacing would signif-icantly improve the local stability of the steel plates. Based on the test results, numerical models were established to further investigate the compressive behavior of SDSC walls. The influences of the key parameters included the faceplate thickness, and the stiffness of the stud and tie plate were discussed in detail. Theoretical models were finally recommended to estimate the buckling stress, the axial compression stiffness, and the ultimate bearing capacity of SDSC walls, which were effective and accurate in evaluate determining the axial compression per-formance of these new composite walls.