PROGRESS IN THE RESEARCH ON FRP-CONCRETE-STEEL DOUBLE-SKIN TUBULAR MEMBERS

Hybrid FRP-concrete-steel double-skin tubular member is a new form of hybrid structural member composed of an inner steel tube，an outer FRP tube and a concrete infill between them． In this type of new hybrid member， the three constituent materials are optimally combined to achieve several advantages not available with existing columns． The two tubes may be concentrically placed to produce a section more suitable for compression members， or eccentrically placed to produce a section more suitable for flexural members． This paper summarizes the following areas that have received many researches: the failure mode and the influence factors under different loading， the formulas to calculate ultimate capacity under different loading．