Compressive behavior of FRP-UHPC-steel double-skin tubular columns

Abstract

Hybrid fiber-reinforced polymer (FRP)-concrete-steel double-skin tubular columns (DSTCs) have been proved an effective structural form to achieve both high strength and ductility. While existing studies on such columns were mainly focused on the use of normal-strength/high-strength concrete as infilling materials, the use of ultra-high-performance concrete (UHPC) to improve the behavior of such columns is attracting increasing attention. For the same demand on load-carrying capacity, the use of UHPC in DSTCs can largely reduce the cross-sectional area and thus the weight of DSTCs, improving the seismic performance of DSTCs. On the other hand, the use of UHPC in DSTSs is able to achieve a much higher load-carrying capacity if the size of the compressive member is limited. To date, limited research has been focused on the compressive behavior DSTCs with UHPC. This paper presents an experimental study on the behavior of DSTCs with UHPC under concentric compression, with the studied parameters being the thickness of FRP tube, the steel fiber content of UHPC, the thickness of steel tube and the void ratio of DSTCs. It was found from the test that DSTCs with UHPC possessed high load-carrying capacity as well as excellent ductility, indicating it is a promising form for engineering use in practice.