Restoring force model of steel-recycled concrete composite frame with infilled recycled block wall

To study the restoring force model of steel-recycled concrete composite frame with infilled recycled block wall, the experimental results of two recycled concrete-filled steel tube frames with infilled recycled block walls and three steel-reinforced recycled concrete frames with infilled recycled block walls under low cyclic loading were analyzed. The four broken-line skeleton curve model which was suitable for this kind of composite frame was proposed, and the calculation methods for different stages of the skeleton curve were given respectively. According to the hysteretic characteristics of different frame specimens, the hysteretic loops for steel-recycled concrete composite frame with infilled recycled block wall were simplified by using the treat methods of positive and negative symmetry and sudden drop of bearing capacity, and the restoring force model for different type of steel-recycled concrete composite frame with infilled recycled block wall was established. At the same time, combing the experimental results, the proposed restoring force model was verified. The results show that the established restoring force model can predict the hysteretic behavior of steel-recycled concrete composite frame with infilled recycled block wall well, and it can provide theoretical support for the elastic-plastic time history analysis of this kind of frame structures under earthquake.