Prediction of seismic response of moment resistant steel frames using different hysteretic models for dissipative zones

In this work, the prediction of the seismic performance of moment-resisting (MR) steel frames with full-strength beam-to-column connections was investigated with respect to the variability in the response due to dissipative zone modelling. 4 numerical models with different degrees of sophistication (Smooth Hysteretic Model, Bouc-Wen, Hysteretic and simple Elastic-Plastic models) were utilized, and each one was calibrated against data coming from monotonic and cyclic experimental tests according to a multi-objective approach recently developed by the authors. Subsequently, Incremental Dynamic Analyses (IDA) were performed by considering two different earthquakes (Spitak and Kobe). This preliminary analysis pointed out that the influence of the joint modelling on the overall frame response is negligible up to interstory drift ratio values equal to those conservatively assumed by the codes to define conventional collapse (0.03 rad). Conversely, if more realistic ultimate interstory drift values are considered for the q-factor evaluation, the influence of joint modelling can be significant, and thus the response prediction may require accurate modelling of the joint cyclic behavior.