Analysis on Extension Length of Shape Steel in Transfer Columns of SRC–RC Hybrid Structures

Abstract

Seismic performance of SRC–RC transfer column was analyzed based on the experiment of 16 transfer columns specimens under low cyclic reversed loading, which mainly focus on the extension length of shape steel. Analysis of ductility, bearing capacity, energy dissipation capacity and degeneration ratio of strength were completed. Displacement ductility promotes at first and then reduces with increasing of extension length of shape steel, reaching the peak value when extension length gets close to three fifths of column height. Extension length of shape steel has little effect on bearing capacity, while energy dissipation capacity of transfer columns is influenced by many factors. Three fifths of column height is the rational extension length of shape steel, of which specimens have advanced in energy dissipation, good stability of stiffness and strength. The bond performance between concrete and shape steel decreases with the increasing of extension length of shape steel, and hence the stability of strength decreases. Minimum extension length of shape steel was confirmed and the calculation method was proposed, which is mainly used to ensure the bend yielding of shape steel at bottom section. Moment at the truncation section leads to pull-out effect of steel bars, which enhances with increasing of the moment and section ratio of shape steel. Contraflexure point is at three fifths of column height. If the shape steel extends to contraflexure point, moment of steel truncation section will reach minimum. So the reduce the concrete damage with better deformation ability and mechanical behavior of transfer column.