ABSTRACT

A simple analytical model is proposed to describe the effects of local buckling of circular cross section on the maximum strength and behavior of tubular beam-columns. The behavior is presented in the form of load-deflection and load-shortening relationships. These relationships are developed on the basis of an assumed deflection method coupled with the moment-thrust-curvature relationship including the softening branch of the relationship due to the local cross-sectional distortion. The analytically obtained maximum strength interaction curves of beam-columns show a reasonably good agreement with the available experimental results. The trend of the analytical load-deflection and load-shortening curves is very similar to that of the available experimental results. It is found that the effects of the local buckling on the behavior and strength of tubular beam-columns become more severe with an increase in diameter-to-thickness ratio, and with a decrease in slenderness ratio.