25-08-2017, 09:32 PM
An attempt has been made to model the hysteretic characteristics of unreinforced masonry infilled reinforced concrete moment-resisting frames for the first time. The difficulties encountered in the modelling are discussed and a new model, The Trilinear Hysteresis Model has been proposed for capturing the hysteretic response of infilled frames. This model incorporates the stiffness and strength contributions of the masonry infill to the overall response of the frame. The critical parameters influencing the behaviour of masonry infill frames are identified, and a parametric study is conducted to study the affects of the same. The inelastic response spectra, and from those the ductility reduction factor spectra, are obtained for the Uttarkashi earthquake strong motion data and some other strong ground motions widely used in seismic analysis. Based upon the results of the study, it has been concluded that the presence of the infill significantly reduces the ductility demand on the frame members. The infill-to-bare frame stiffness ratio is observed to be the most influential