Experimental investigation of damage behavior of RC frame members including non-seismically designed columns

                                             Chen Linzhi, Lu Xilin, Jiang Huanjun and Zheng Jianbo

State Key Laboratory of Disaster Reduction in Civil Engineering, Tongji University, Shanghai 200092, China

Abstract: Reinforced concrete (RC) frame structures are one of the mostly common used structural systems, and their
seismic performance is largely determined by the performance of columns and beams. This paper describes horizontal cyclic
loading tests of ten column and three beam specimens, some of which were designed according to the current seismic design
code and others were designed according to the early non-seismic Chinese design code, aiming at reporting the behavior
of the damaged or collapsed RC frame strctures observed during the Wenchuan earthquake. The effects of axial load ratio,
shear span ratio, and transverse and longitudinal reinforcement ratio on hysteresis behavior, ductility and damage progress
were incorporated in the experimental study. Test results indicate that the non-seismically designed columns show premature
shear failure, and yield larger maximum residual crack widths and more concrete spalling than the seismically designed
columns. In addition, longitudinal steel reinforcement rebars were severely buckled. The axial load ratio and shear span ratio
proved to be the most important factors affecting the ductility, crack opening width and closing ability, while the longitudinal
reinforcement ratio had only a minor effect on column ductility, but exhibited more influence on beam ductility. Finally, the
transverse reinforcement ratio did not influence the maximum residual crack width and closing ability of the seismically
designed columns.

Keywords: reinforced concrete frame member; cyclic test; hysteresis behavior; damage behavior; seismic performance




กก