Experimental research and finite element analysis on seismic behavior of CFRP-strengthened seismic-damaged composite steel-concrete frame columns

Four composite steel-concrete frame columns were constructed to investigate the seismic performance of seismic-damaged composite steel-concrete frame columns strengthened with carbon fiber reinforced polymer. The test consisted of pre-damage loading, rehabilitation with carbon fiber reinforced polymer and destruction tests under lateral cyclic loading. The effectiveness of strengthening seismic-damaged columns with carbon fiber reinforced polymer and the strengthening effect on different degrees of seismic damage were studied. Also, based on the test data, various parameters were obtained, including the hysteretic loops, skeleton curves, axial compression ratio, number of pasted layers of carbon fiber reinforced polymer, ductility, dissipative ability, ultimate strength, stiffness degradation, etc. The results revealed that the failure mode of all the columns was bending failure. The study indicates that the rehabilitated columns can reach or even exceed the level of their original seismic performance before seismic damage up to a certain extent of damage level. Composite steel-concrete frame columns strengthened with carbon fiber reinforced polymer sheets were simulated using the finite element analysis software ABAQUS. The comparison of the results of the conducted analytical study with the experimental results revealed that they are basically consistent with each other.