Experimental behaviour of concrete-filled steel tubular members under lateral shear loads

This paper deals with an experimental investigation on the shear behaviour of concrete-filled steel tubular (CFST) members. A total of 38 specimens with either circular or square cross-sections were tested. Among these specimens, four were subjected to shear and the rest were subjected to combined axial compression and shear. The main parameters considered were the axial compression ratio (n = 0-0.75), shear span-to-depth ratio (m = 0.075-0.75), concrete strength (fcu = 31.9 or 57.4 MPa), steel ratio (αs = 0.070 or 0.108) and steel yield stress (fy = 338.3 or 415.7 MPa). The test results showed that, all the CFST specimens exhibited ductile characteristics. The influences of the parameters on the failure mode, load vs. deformation relationships, shear capacity, and strain development of the tested specimens were investigated. Finally, an existing simplified model for predicting the shear capacity of CFST members under combined compression and shear was also assessed.