Stiffened concrete-filled steel tubes : a systematic review

The behavior of concrete filled steel tubular (CFST) elements with different types of stiffening measures has been wildly investigated during the past two decades through experimental, analytical, and numerical approaches. The previous studies highlighted the importance of the presence of internal and external stiffeners to enhance the structural performance of CFST elements under different loading conditions. In this paper, a systematic methodology is proposed in order to rigorously review the current knowledge in literature about stiffened CFSTs. The reviewed studies include tests of static axial compression, pure bending and combined of static loading actions as well as the cyclic behavior and the fire resistance. A coherent taxonomy regarding the research of stiffened CFSTs is proposed based on the loading conditions besides their cross-sectional shape and type of stiffeners. The study also presents a number of practical applications of stiffened CFSTs in different engineering projects. Finally, concluding remarks, current research gap and future research directions on stiffened CFST are provided and discussed