Damage and quantitative indexes for steel reinforced concrete column with T-shaped section

Abstract

This paper presents an experimental investigation on damage performance of nine steel reinforced concrete (SRC) columns with T-shaped section under different loading paths. The monotonic loading, low cyclic reversed loading and mixed loading were applied to specimens along the flange of specimen. Furthermore, different axial compression ratios and steel ratios were used to study the damage of specimen. The failure modes were observed and the load-displacement curves were analyzed. The results indicate that the specimens mainly showed the feature of bending failure accompanied by bond failure characteristic at the end of loading. The load-displacement curve was plump and symmetrical without obvious pinch under the low cyclic reversed loading. The ductility coefficient lied within the range of 5.34–9.41, which indicates that these columns had better deformation capability. Based on the experimental results, a modified damage model considering deformation and energy dissipation was proposed, where the effects of concrete cracking, loading path and effective energy dissipation on damage were studied. Moreover, the damage index at each loading stage was calculated. Meanwhile, the level of seismic performance of SRC T-shaped column was divided into five levels, namely the normal use, the basic normal use, the temporary use, the post-repair use, and the near serious damage. Many SRC T-shaped columns were chosen as the analysis samples to obtain the displacement angles under different loading stages. Based on statistic results, the corresponding relationship between quantitative index of displacement angle and the damage index was established.