Axial compressive behavior of corroded concrete filled circular steel tubular stubs strengthened with CFRP

This paper presents the details of experimental and numerical investigations on the static performance of circular CFRP- corroded concrete filled steel tubular (C-CFRP-CCFST) stubs, circular corroded concrete filled steel tubular (C-CCFST) stubs and circular concrete filled steel tubular (C-CFST) stubs under axial compressive load. To simulate the thickness reduction caused by corrosion, the steel tube was milled at mid-height region of specimen. A total of 25 specimens, including 12 C-CFRP-CCFST stubs, 10 C-CCFST stubs, and 3 C-CFST stubs, were tested. The test results show that the compressive strength of C-CCFST specimens in contrast to the C-CFST stubs were decreased by 2.9%–22.9% depending on the corrosion level of steel tube and were increased by 25.8%–49.8% after the C-CCFST stubs were strengthened with CFRP. On the basis of the experimental investigation, a series of finite element models (FEMs) were developed to analyze the behavior of C-CFRP-CCFST stubs, C-CCFST stubs, and C-CFST stubs, regarding failure modes, load-displacement relationship, and stress distribution. Employing the proposed FEMs, parametric studies were then carried out to study the influence of principle factors on the compressive performance of C-CFRP-CCFST stubs and C-CCFST stubs comprehensively. Equations were proposed for calculating the ultimate strength of C-CFRP-CCFST and C-CCFST stubs based on the numerical analysis results. Additionally, parametric studies on the corrosion members with discrete corrosion regions (DCR) were also carried out, and equations for predicting the ultimate strength of such members were proposed.