Resilience model of SRC columns with cross-shaped encase steel

Based on the test results of 21 steel reinforced concrete (SRC) columns reported in references whose encased steel ratios are lower than 20%, the key points of the load-displacement skeleton curves of SRC columns are established. The skeleton model is defined through the yield point, the peak point and the residual point. Influencing parameters such as the ratio of encased steel, the transverse reinforcement characteristic value, the size of the cross-section, etc., were considered in the study. Restoring force models applicable to cross-shaped encase steel SRC columns with ratio of encased steel between 10%-20% and fewer than 10% are suggested respectively. The main results show that the influencing parameters have different effects on the values of key points. The proposed tri-linear restoring force model considering various influencing parameters can predict the test results closely, therefore is applicable to nonlinear dynamic analysis of structures with such kinds of SRC columns.