Static Behavior of Axially Compressed Circular Concrete Filled CFRP-Steel Tubular (C-Cf-CFRP-St) Columns With Moderate Slenderness Ratio

Abstract

Thirty-two specimens are experimentally tested in this paper to study the static performance of axially compressed circular concrete filled CFRP-steel tubular (C-CF-CFRP-ST) columns. The tested results indicate that, for columns with relative small slenderness ratio, failure is dominated by the strength loss of the materials. However, for columns with relative large slenderness ratio, failure is controlled by instability. The load versus deflection curves at the mid-height of the composite column can be divided into three stages, i.e., elastic, elasto-plastic and softening stage. Analyses of the tested results show that distribution of longitudinal strains in the steel tube over depth on the cross-section is approximately linear, and the steel tube and its outer CFRP material can cooperate both longitudinally and transversely. The longitudinal strain and the transverse strain at a point have opposite signs, and the steel tube under longitudinal tension has no transverse confinement effect on its concrete. The Deformed modes of the columns, the axial load verses deflection curves at the mid-height, the axial load verses axial shortening curves and the stresses in the steel tube are simulated by using finite element method. The calculated results agree well with the experimental results to prove the accuracy of the finite element model. Stresses in the concrete, the steel tube and the CFRPs are analyzed by using finite element method. The numerical results show that the interaction force between the steel tube and the concrete decreases gradually from compressive region to tensile region. The adhesive strength between the concrete and the steel tube has little effect on the critical buckling load and on the elastic stiffness of the columns. Equation for calculating the critical buckling load of the composite columns is presented, and the estimated results agree well with the experimental results.

A Model for Predicting Moment-Curvature Behavior of Self-Stressing Ssacfst Columns Under Low Cyclic Loading

“…Concrete-filled steel tubular (CFST) column has been extensively applied in bridge engineering, power transmission towers, and high-rise buildings due to its significant merits of high load capacity, favorable ductility and convenient construction. Numerous experimental and theoretical investigations on CFST columns have been performed and fruitful research results have been achieved [15][16][17]. However, the hardening shrinkage of core concrete may reduce the durability and affect the safety of structure.…”

Structural Performance of Infilled Steel–Concrete Composite Thin-Walled Columns Combined with FRP and CFRP: A Comprehensive Review

“…Short CFRP-confined SCTWCs have been the subject of previous investigations concerning the behavior of the CFRP-confined SCTWCs. However, the study in this area is still quite restricted, and the columns utilized in actual engineering tend to be substantially thinner [ 14 , 15 ]. Recent years have seen a lot of experimental and analytical studies on the behavior of undamaged short SCTWCs reinforced with the CFRP sheets [ 16 , 17 , 18 ].…”

Analytical model for circular F-STC stub columns under concentric compression

“…Most of the existing studies have focused on the performance of FRP confined CFST columns under concentric compression (Che et al, 2012; Ding et al, 2018; Hu et al, 2011; Li et al, 2018; Lu et al, 2014; Park et al, 2011; Tao et al, 2007; Wang et al, 2016, 2017; Wei et al, 2014; Xiao et al, 2005). Moreover, theoretical models have been proposed to simulate the stress–strain behavior of FRP confined CFST columns, which can be divided into two categories: design-oriented model and analysis-oriented model.…”