Three-dimensional response of steel moment-resisting buildings under seismic sequences

This study examines the response of three-dimensional (3-D) steel moment-resisting buildings having 3-, 9-, and 20-story height under bi-directional attack of real seismic sequences with different earthquake ground motion features. For this purpose, 3-D analytical models were developed for each building, which include or not include interior gravity frames. The fracture behavior in beams included in perimeter moment-resisting frames and the bending capacity of interior beams in gravity frames was taken into account in the modeling process. The seismic response of the 3-D building models, in terms of lateral interstory drift demands, was also compared with the response of their corresponding two-dimensional (2-D) bare frame model to highlight differences in modelling criteria. It is shown that differences among 2-D and 3-D building models depend on the type of seismic sequence. When differences arise, it is clearly illustrated that the 3-D building models experience different response than the 2-D model. Between the 3-D models, it is shown that the seismic response is different, with differences depending on the angle of incidence of the orthogonal components of the seismic sequences and the number of stories. This study demonstrates that the modelling approach in 3-D models has significant influence in seismic response of steel framed-buildings under seismic sequences.