Static strength of CFRP-strengthened preloaded circular concrete-filled steel tube stub column columns – Part II: Theoretical and numerical analysis. (March 2023) - Xiong, C.N.
Abstract: Carbon fiber reinforced polymer (CFRP) has high strength and is lightweight, and it can be used to strengthen circular concrete-filled steel tubes (CFSTs). For CFSTs in service, they are usually subjected to preloading. By considering the strain lag of CFRP, a theoretical model for analyzing CFRP-strengthened preloaded CFST stub columns is presented, and corresponding equations are derived for calculating the yield strength and the ultimate strength. Using the death and birth technique of CFRP element, finite element (FE) modeling is also presented to simulate the failure process of a CFRP-strengthened preloaded CFST stub column. The reliability and the accuracy of both theoretical equations and the FE model are evaluated by comparing the predicted results with experimental results reported in Part I. Finally, the CFRP-strengthening efficiency for the yield strength and the ultimate strength is assessed through the parametric study on 48 models. The effects of CFRP layers and preloading percentage on the strength of CFRP-strengthened preloaded CFST stub columns are also discussed. Highlights: Theoretical model for analyzing the static strengths of preloaded CFRP-CFST stub columns was established. Equations for calculating yield strength and ultimate strength of preloaded CFRP-CFST stub columns were presented. Finite element model for analyzing the failure process of preloaded CFRP-CFST stub columns was established.