Probabilistic seismic demand assessment of steel moment frames with side-plate connections

Seismic performance of Steel Moment-Resisting Frames (SMRFs) with side-plate connections has been investigated, incorporating record-to-record uncertainties. Based on experimental and finite element results, a connection model was proposed and calibrated to represent the side-plate connection behavior. Three code-conforming special SMRFs, varying in height, were designed and were modeled using fully nonlinear assumptions and incorporating the connection model calibrated in the previous step. Subsequently, more than 1500 Nonlinear Dynamic Analyses (NDAs) were performed within the Incremental Dynamic Analysis (IDA) procedure and were used as input to the Performance-Based Earthquake Engineering (PBEE) methodology. The structures performance was then quantitatively assessed in terms of Limit State (LS) frequency and “seismic demand hazard curves”. The effect of neglecting some level of accuracy in the structural modeling process on the predicted performances was also assessed disregarding calibrated connection behavior and employing two alternate sets of building representatives. The performances predicted by inaccurate conventional models, through about 3500 additional NDAs, were then assessed qualitatively, and the significance of incorporating accurate structural models in the performance evaluation process was highlighted with reference to the obtained comparative results.