STUDY ON SHEAR PERFORMANCE OF RC-ENCASED CFST COLUMNS WITH INTERFACIALLY WELDED ANNULAR REBARS

To study the shear behavior of RC-encased CFST columns with interfacially welded annular rebars, the transverse shear static test and numerical simulation of six composite column specimens were carried out with the spacing and the diameter of annular rebars as research parameters, and the influence laws of various parameters on failure process, failure mode, load-midspan deflection curve and shear bearing capacity of the specimens were investigated. The results show that the failure modes of composite columns with different arrangements of interface annular rebars were basically the same, and all of them exhibited oblique pressure failure. The stress process of the specimen can be divided into four stages: elastic stage, elasto-plastic stage, hardening stage and failure stage. With the decrease of the spacing of interface annular rebars, the shear bearing capacity of the specimen was significantly improved, with the maximum increase of 22%. Increasing the diameter of interface annular rebars can improve the shear capacity of the specimen, but the effect was limited, and the maximum increase was only 6.1%. The validity of the finite element model was verified by the experimental data, and the stress states of the finite element model at different stages were further analyzed, and the shear mechanism of this kind of composite column was clarified.