Experimental study on seismic behaviors of RC pier columns under different loading paths

Pseudo-static tests of seven reinforced concrete(RC)pier columns with the shear span ratio of 3 were conducted to study the influence of different loading paths on the seismic behaviors of RC pier columns. The results demonstrate that the specimens are failed in the compression-bending mode, which was evident by the presence of buckled, ruptured longitudinal reinforcement or crushed concrete, as well as plump later force-displacement hysteresis loops. The effects of the loading cycle number, the displacement amplitude and the displacement increment on the seismic behaviors of the RC pier columns are evident. According to the analysis of the displacement ductility, the energy dissipation capacity and the damage index, the increase of the loading cycle number at the same displacement amplitude impairs the seismic performance, accelerates the damage accumulation of the specimen, and reduces the deformation capacity of the specimen. The displacement ductility of the specimen drops by about 22% when the number of the loading cycles increases from 3 to 10. The cycle degradation effect caused by the increase of the loading cycle number is more significant at the large displacement amplitude after the yielding load. With the same loading cycle number, the increase of the displacement amplitude can reduce the failure cumulative damage of the specimens and the degradation of the bearing capacity, and increase the displacement ductility. © 2020, Editorial Department of Journal of Southeast University. All right reserved.