Study on seismic behavior of encased steel jacket-strengthened earthquake-damaged composite steel-concrete columns

In order to study the seismic behavior of earthquake-damaged composite steel-concrete columns strengthened by enveloped steel, based on current design codes, four composite steel-concrete column models were designed and manufactured. Destructive tests on the models under low-cyclic loading were then carried out. The feasibility and effectiveness of earthquake-damaged columns strengthened by enveloped steel and the reinforcement effect on different levels of seismic damage were studied. The results show that enveloped-steel-strengthened earthquake-damaged composite steel-concrete columns meet the strong column-weak beam requirement of seismic design, and the failure mode of all the columns was in bending. The performance of the rehabilitated columns can reach or even exceed the level of their original seismic performance before seismic damage. Composite steel-concrete frame columns strengthened by enveloped steel were also simulated using the finite element (FE) analysis software ABAQUS. The analytical study was conducted and compared with the experimental results, and it was basically consistent with the experimental data.