Study on deformation-based performance index limits of steel reinforced concrete columns

The method of dividing performance levels for steel reinforced concrete (SRC) columns and the physical damage states and repair methods corresponding to individual performance level were determined. The load carrying capacity of the specimens and the edge strain statuses of the concrete, rebar and the steel in the critical regions were used as the control condition to determine the limit states. By using ABAQUS, 360 SRC column models which were designed according to the Chinese codes were analyzed to get the limit rotations for each performance levels. The effects of axial load ratio, steel ratio, stirrup ratio, shear ratio and types of encased steel on the limit rotations were also analyzed. The results indicate that the types of encased steel have little influence on the limit values, while axial load ratio has the largest effect on the limit rotations for all performance levels. In addition, steel ratio, stirrup ratio and shear ratio have obvious effects on some performance levels. Finally, the statistical characteristic values and the calculation formula for the limit rotations of SRC columns were obtained by regression analysis. The research results can be utilized for the performance based seismic design and seismic performance evaluation of steel-concrete hybrid structures. © 2016, Editorial Office of Journal of Building Structures. All right reserved.