Development of new nonlinear dynamic response model of reinforced concrete frames with infill walls

The complex behavior of reinforced concrete frames with infill walls under earthquake loads requires a realistic conceptual model that recognizes changes in strength and stiffness occurring during loading. Accordingly, a new hysteresis model is developed in this article for such reinforced concrete frames to investigate the ultimate damage state given a ground motion. Using this model, the infilled frame can be represented as a single-degree-of-freedom system for computationally efficient dynamic in-plane response analysis. A backbone curve is developed first to provide an envelope within which load–displacement paths occur. Then, the load reversal effects are described and integrated into the backbone curve to obtain the hysteresis model. The hysteresis model developed in this article is checked using data from 11 laboratory experiments carried out by other researchers. The applicability of the hysteresis model is also illustrated on a laboratory specimen that was tested by other researchers under base excitation.