Experimental investigation and analysis on flexural behavior of CFSTTC beams

A series of experiments and analyses on the flexural behavior of concrete filled steel tubular truss composite (CFSTTC) beams were presented in this paper. Flexural tests were performed with two CFSTTC beams with different web configurations: one specimen has the transverse and diagonal braces and the other one only has transverse braces. The failure modes, deflection shapes, load capacities, strain responses at different locations as well as the local buckling phenomenon on the two tested specimens were evaluated. Some suggestions were proposed to prevent the local buckling on CFSTTC structures. Finite element (FE) models were developed and verified by the obtained experimental results. In addition, parametric studies were conducted to investigate the influence of core concrete in chords, concrete slab etc. A simplified method was proposed in this paper to predict the flexural strength of CFSTTC beams with fully or partially concrete filled chords. The proposed method was validated on the basis of the experimental and numerical results.