modeling considerations for performance based seismic design of steel moment resisting frames

performance based seismic design (pbsd) of buildings entails adopting nonlinear static or dynamic procedures for evaluating inelastic system responses. with the increasing level of awareness of the engineering community about seismic performance and safety of the structures, pbsd turns to be more popular in everyday design of buildings. various models such as fiber element, finite length plastic hinge (flph) and concentrated plastic hinge (cph) models can be used for this purpose. however, system responses can be sensitive to characteristics of the selected finite element model, predefined material behavior and damping characteristics. hence, practitioners’ perception regarding modeling issues has to be improved. this paper provides more insights into performing reliable nonlinear static or dynamic analyses by presenting a relatively detailed discussion on the subject and by considering a few case studies. three steel moment resisting frames are considered to compare system responses obtained from the nonlinear dynamic procedure (ndp) and nonlinear static procedure (nsp) proposed by asce 41-17. all problems are solved by cph, flph and fiber element models to investigate the performance of each model. it is concluded that the cph and flph models are the most promising approach for being used by practitioners while fiber element models are more suitable for researchoriented purposes.