Study on confinement mechanism of core concrete in steel tubular-corrugated steel plate confined concrete columns

Abstract

This paper investigated the confinement mechanism of core concrete in steel tubular-corrugated steel plate confined concrete (S-CSC) column. Fourteen S-CSC columns and one CFST column were tested under axial compression, and the corresponding failure modes and load-displacement curves were observed. The strain changes of corrugated steel plate at different positions and square steel tubular were measured. Combined with the test results, the influences of some parameters including the section size, the steel tubular width, the wave height of corrugated steel plate, the thickness of corrugated steel plate and etc. on the strength index of core concrete and the ductility index of the specimens were analyzed. And the confinement mechanism of the core concrete in S-CSC column was studied. It was found that the confinement coefficient ξ which considered the influence of material strength and section size on the confinement effect of core concrete can reflect the confinement mechanism of core concrete effectively. Based on L.-H. Han's model, a constitutive relation for core concrete in S-CSC column by modifying key parameters was proposed and implemented in finite element simulation to predict the mechanical behaviors of axially loaded S-CSC column from the results of the tests. Comparing the test results of S-CSC columns which were described in this paper and the FE results, the satisfactory agreement was observed. Finally, it is verified that the size effect has no effect on the strength index of core concrete in S-CSC column basically.