RESEARCH ON THE SEISMIC BEHAVIOR OF FRAME STRUCTURES WITH T-SHAPED STEEL REINFORCED CONCRETE COLUMNS AND STEEL BEAMS

To study the seismic behavior of frames with T-shaped steel reinforced concrete columns and steel beams, a pseudo-static test of a 1/3 scaled, 3-story 2-bay specimen was carried out. The main results such as the failure pattern, hysteretic and skeleton curves were obtained. The ductility, energy dissipation capacity and degradation of stiffness and strength of the specimen were analyzed. Numerical simulations were conducted with the fiber model to study the effects of different design parameters such as the axial compression ratio, steel ratio and concrete strength on the seismic performance of the frame. It was demonstrated that the specimen exhibited a beam-hinge failure mode under the condition of horizontal cyclic loading. The specimen had good ductility and energy dissipation capacity and it met the seismic design requirements of strong column-weak beam, strong shear-weak bending and strong joint-weak pole. The axial compression ratio has great influence on the performance of the specimen after yielding. With the increase of the axial compression ratio, the strength and ductility of the structure will decrease. It is necessary to control the axial compression ratio in a reasonable range in the design. The steel ratio mainly affects the initial stiffness and ultimate strength, while its increase can effectively improve the seismic performance of the frame. The increase of concrete strength can increase the ultimate strength of the structure, but reduce the ductility slightly. It is of great significance to consider concrete strength comprehensively in the design. The research results can provide reliable support for the design of this kind of structures.