Slender CFST columns strengthened with textile-reinforced engineered cementitious composites under axial compression

摘要

Textile-reinforced engineered cementitious composites (TR-ECCs) have proven effective for application in structural retrofitting. This paper presents a feasibility study on slender concrete-filled steel tube columns strengthened with TR-ECC. A total of 31 specimens were fabricated and tested under axial loads. Parameters including length-to-diameter ratio, number of textile layers, diameter-to-thickness ratio, and in-filled concrete strength were considered. The experimental results showed that both the load-carrying capacity and stiffness of the slender columns significantly improved after strengthening. The slender strengthened columns failed owing to the loss of stability. Based on the test results, a finite element model was established to further study the mechanical properties. The calculation results were validated to be reliable when compared with the test results. Parameter studies indicated that the enhancement in load-carrying capacity contributed by the confinement of TR-ECC was weakened as the length-to-diameter ratio increased. The main function of the strengthening layer was to improve the ductility when the length-to-diameter ratio of the specimen was relatively large.