Seismic resistance capacity of steel reinforced high-strength concrete columns with rectangular spiral stirrups

In this paper, several experimental investigations on seismic resistance capacity of steel reinforced high-strength concrete (SRHC) columns with rectangular spiral stirrups are presented. Tests were carried out on eleven SRHC columns with rectangular spiral stirrups and one comparative SRHC column with an ordinary stirrup arrangement under low reversed cyclic loading to investigate their failure patterns, characteristic loads and displacements, hysteresis loops, skeleton curves, inter-story drift ratios and ductility coefficients, energy dissipation capacities and stiffness degradation. Range analysis and variance analysis methods were used to analyze the data from the experiments. The results showed that the failure patterns of the test specimens changed from shear baroclinic failure to shear-bond and flexural failure, as the shear span ratio was increased. In addition, the shear span ratio is the main factor that had a significant effect on the carrying capacity of the test specimens. The carrying capacity of the SRHC specimens increased gradually, but their ductility decreased as the axial compression ratio was increased. The ductility coefficients of the SRHC specimens with the normal stirrup and the rectangular spiral stirrup were 3.01 and 3.27, respectively, indicating that the columns with the rectangular spiral stirrup had better deformation capacity. Furthermore, the inter-story drift ratios of all the columns with the rectangular spiral stirrup in elastic phase and elastic-plastic phase were in the range of 1/200 to 1/66 and 1/26 to 1/17, respectively, which are much larger than the limit value specified by the seismic design code. In addition, the SRHC columns with rectangular spiral stirrups exhibited plumper hysteresis curves and higher energy dissipation than the SRHC column with ordinary stirrup. Thus, the SRHC columns with rectangular spiral stirrups showed good seismic resistance capacity. (C) 2019 Elsevier Ltd. All rights reserved.