The buckling behaviors of specimens can be attributed to stiffening mechanisms, in which the stiffeners delay the local buckling and almost fully restrain the out-of-plane deformation of steel tubes at the location of welds.
The results deduced from experiment on the tubes’ buckling modes and stiffener mechanisms not only confirm the conclusions of the author's previous experiment [1], but also investigate new stiffeners’ mechanisms and more comprehensively summarize the common mechanisms among different stiffeners. The mechanisms of stiffeners in this
experiment are described as follows.