Earthquake damage evaluation of T-shaped SRC composite column-steel beams in 3D connection joints

This paper focuses on the study of seismic-induced damage assessment of three-dimensional (3D) joints connected with T-shaped steel reinforced concrete (SRC) column-steel beams. Low cyclic reversed loading tests on one planar joint and nine 3D joints were firstly conducted to intensively investigate the seismic behavior of the hybrid joint. The damage index calculation models such as the displacement-based type, energy-based type and displacement & energy-based type were discussed and applied for all the specimens according to the experimental results. In addition, the effects of shape steel configuration type, loading angle and axial compression ratio on the damage development and accumulation for test specimens were analyzed through Park-Ang model. The analysis results show that the selected parameters of damage-index calculation models have great effect on the developing trends of damage curves. Under the same ability of relative deformation, the accumulated damage of the specimens configured with T-shaped steel are much larger than that of the specimens configured with channel-shaped and solid-web steels; moreover, the degree of damage accumulation for the specimens under 30° and 60° loading angles is slightly larger than that of the specimens under 45° loading angle. The specimens subjected to a lower axial force level have a faster damage development, but the damage accumulation is smaller than that of the specimens under a higher axial compression ratio.