Seismic behavior of solid steel reinforced concrete middle frame with special-shaped columns

Through the experimental study on the model of a two-bay and three-story middle frame consisting of reinforced concrete beams and solid steel reinforced concrete (SRC) special-shaped columns under low cyclic reversed loading, the failure process and pattern were observed. The mechanical behavior such as load-displacement hysteretic loops and skeleton curves, load carrying capacity, inter-story drift ratio, ductility, energy dissipation and stiffness degradation of the frame were analyzed. Test results show that the solid SRC middle frame with special-shaped columns is a typical strong column and weak beam structure. The failure mechanism is the beam-hinge mechanism. The hysteretic loops are a plump. As the frame fails, the average of the overall ductility factors is 5.5. The equivalent viscous damping coefficient is 0.249. The ultimate elasto-plastic story drift rotation is between 1/39 to 1/13, indicating a high level of collapse resistance. The solid SRC middle frame shows excellent seismic behavior, and can be adopted in the construction in high seismic fortification zones.