Seismic behavior of FRP-concrete-steel double skin tubular columns with a rib-stiffened Q690 steel tube and high-strength concrete

Fiber-reinforced polymer (FRP)-concrete-steel double skin tubular columns (DSTCs) are a form of novel hybrid columns with a particular merit of lightweight due to the existence of the void core. Utilization of high-strength materials (e.g., high-strength steel (HSS) and high-strength concrete (HSC)) tubes in DSTCs amplifies the advantage of DSTCs by earning a further decrease in the dead weight. In this study, behavior of DSTCs with HSC and a rib-stiffened HSS tube (referred to as R-DSTCs in this paper) under seismic loadings was experimentally investigated. The influences of the quantity of stiffeners, the FRP tube thickness and the axial load ratio on the seismic behavior of R-DSTCs were investigated. The test results demonstrate that DSTCs with HSC and HSS tubes exhibit a good seismic behavior, and an increase in the number of ribs leads to an increase in the lateral loading capacity, a small increase in the stiffness, a significant increase in the resistance to stiffness degradation and an increase in the energy dissipation of the R-DSTCs. Additionally, the axial load ratio and the GFRP tube thickness has a small effect on seismic performance of DSTCs. •Behavior of R-DSTCs with HSC and HSS tube under seismic loading is explored.•R-DSTCs experience severe HSS tube buckling and fracture failure, therefore the effects of GFRP tube thickness is small.•An increase in the number of stiffeners leads to an increased strength, stiffness, ductility and energy consumption capacity of R-DSTCs.•The axial load ratio only has a small effect on performances of R-DSTCs.