Hysteresis Models for Reinforced Concrete

Nonlinear dynamic response of a simple reinforced concrete specimen is studied using five different hysteresis models: the Takeda, elasto-plastic, bilinear, Clough, and the Q-hyst model. These models range from simple but unrealistic (the elasto-plastic model) to complicated but realistic (the Takeda model). The Takeda model is used as the basis to evaluate the other models, and to explain the influence of different features used in each model. It is shown that stiffness degradation effects associated with unloading and load-reversal stages had a substantial effect on the amplitudes, waveform, and frequency content of displacement response history of the specimen studied. It is further shown that the Q-hyst model, which takes degrading effects into account while it is simple, resulted in a response history which was in excellent agreement with that obtained using the Takeda model.