EXPERIMENTAL STUDY ON AXIAL COMPRESSIVE CAPACITY OF CORRODED CONCRETE FILLED CIRCULAR CFRP-STEEL TUBE STUBS

The axial compressive capacities of non-corroded concrete filled circular steel tube (T4.5-CFST) stubs, corroded concrete filled circular steel tube (C-CCFST) stubs, and CFRP-corroded concrete filled circular steel tube (CFRP-C-CCFST) stubs were studied experimentally. The corrosion defects were simulated by material removal. A total of 19 specimens were tested, including one T4.5-CFST stub, eight C-CCFST stubs, and ten CFRP-C-CCFST stubs. Within the ranges of the test parameters, the test results show that the ultimate strengths of the C-CCFST specimens were lower than those of the T4.5-CFST specimen by 3.0% to 22.9%. The ultimate strengths of the CFRP-C-CCFST specimens were increased by 26.8% to 49.8% as compared with those of the C-CCFST specimens. Compared with the C-CCFST specimens, the CFRP-C-CCFST specimens had greater axial compressive stiffness and ultimate strengths due to the confinement effect of the CFRP. The ultimate strengths of the CFRP-C-CCFST specimens were higher than that of the T4.5-CFST specimen, indicating that the specimens strengthened by CFRP have better mechanical performance. The local buckling of the steel tubes with corrosion defects was effectively restrained by the CFRP. In addition, the ultimate strengths of the CFRP-corroded concrete filled circular steel tube stubs were studied theoretically. The accuracy was verified by the experimental results.