Abstract:
To improve the seismic performance and damage tolerance of reinforced concrete (RC) columns, fiber reinforced concrete (FRC) was used to replace normal concrete in column end regions. Nine FRC specimens with different axial load ratios and shear span ratios and one RC column for comparison purposes were designed. The crack and failure modes of specimens under low cycle reversed loading were observed. The hysteretic characteristics, deformation capacity, energy dissipation capacity and stiffness degradation trend were also investigated. Test results showed that FRC columns with a shear span ratio of 2.0 was subjected to flexural failure, and the strength and stiffness degraded at a lower rate with a better deformation capacity, energy dissipation capacity and damage tolerance compared with normal concrete columns. The axial load ratio and shear span ratio had a significant effect on deformation capacity and energy dissipation capacity of FRC columns. The FRC columns with only shear resisting stirrups satisfied the deformation and energy dissipated requirements. The finite element model that based on experimental verification for cantilever columns with FRC used in the column end region was established by using the finite element software package OpenSees, and the whole process simulative analysis and parametric analysis were attained. Results showed that the calculated hysterics curves agreed well with experimental hysterics curves, and the shear span ratio, axial load ratio and FRC strength affected the bearing capacity of columns.