Abstract:
To investigate the seismic behavior of RC frame beams under different loading protocols, a pseudo-static experiments of RC frame beam specimens were carried out by four kinds of loading protocols. The results showed that the earlier the peak displacement (the displacement corresponding to the peak load) appeared, the more proportion of shear deformation of the specimens would be brought out in the damage state, and the wider the maximum crack width of the specimens would be. Meanwhile, the rotation of plastic hinge and ductility coefficient of the specimens were smaller, but the plastic hinge height remained the same. With the change of cyclic displacement amplitude and number of cycles, the stiffness and strength degradation of RC frame beams would be different. It showed that the stiffness and strength degradations of RC frame beams with larger displacement amplitude cycle (or more cycles) were faster than that with smaller displacement amplitude cycle (or fewer cycles) in the softening branch of the hysteresis curves. Moreover, the energy dissipation capacities of the RC frame beams were different under different loading protocols. The earlier the peak displacement appeared, the lower the energy dissipation capacity of RC frame beam tends to be.