Test on seismic performance of frame structure of steel reinforced concrete beam and steel-tube encased concrete column

This paper conducted a test on two frame structures of steel reinforced concrete beam and steel-tube encased concrete column under horizontal low cyclic loading. The test process and failure mode were observed, and the hysteretic behavior, skeleton curves, stiffness degradation, energy dissipation, and residential deformation of the two frames were studied. Meanwhile, the law of strain values of longitudinal bars, flanges and steel-tube in the beam and column end was analyzed carefully, and the order of plastic hinges was given. The test results show that hysteretic curves of the two specimens are plump, and one also behaves good energy dissipation when it is prestressed, and they behave good seismic performance. Meanwhile, the hoop strains of steel-tube of plastic hinge in the column bottom changes unevenly during the whole loading, and they could supply effective constraint on compressive concrete. And the cracks could be delayed when the steel reinforced concrete beam is prestressed. Furthermore, the sequence of plastic hinges of the two specimens is 'beam ends before and column bottoms after', so that the mechanism of energy dissipation for beam plastic hinges and a delayed occurring of plastic hinges for column bottom could be achieved.