Study on seismic performance of RC columns strengthened with CFRP-steel tube self-compacting concrete

In order to study the seismic performance of Reinforced Concrete columns strengthened with Carbon Fiber Reinforced Polymer-steel tube self-compacting concrete, seven strengthened columns and one unstrengthened column were designed and manufactured with the main parameters of axial compression ratio, self-compact concrete strength, steel tube shape and steel tube thickness. The hysteresis curve, skeleton curve, ductility, energy dissipation capacity, stiffness, steel tube surface and steel bar strain variation of the specimens were analyzed. The test results show that the strengthened part of the specimen has good cooperative working ability with the RC column, and the failure process and failure mode of the specimen are similar to those of the concrete filled steel tube. Under the action of horizontal reciprocating load, the concrete at the bottom of the strengthened column is cracked; with the increase of horizontal displacement, the hysteresis curve becomes full and the energy dissipation capacity increases. The finite element software ABAQUS is used to model and analyze the specimens. The simulation results are in good agreement with the experimental results. It is proved that the simulation is reasonable and effective in unit selection, contact setting, meshing and material constitutive selection. The hysteresis curve, skeleton curve and failure mode of each specimen are obtained.