Experiment Study on Influence of Initial Stress in Concrete Filled Steel Tubular Latticed Columns under Axial Load

The testing of concrete filled steel tubular (CFST) latticed columns with initial stress had been conducted under axial load. The set-ups subjected to initial stress, the curves of load to deformation as well as the hooping effect were analyzed. The trial results indicate that the CFST columns with initial stress have smaller of combined stiffness and ultimate load-carrying capacity as compared with CFST columns without initial stress. Furthermore, the presence of initial stress will advance the coming of plastic phase, and contemporary, put off the appearances of hooping effect so that it cannot be sufficient exerted, which decrease the ultimate load-carrying capacity at all. Nevertheless, the mechanical behaviour of lacing tubes does not vary with the initial stress and all the lace tubes are stayed in the elastic phase during the testing.