Abstract:
Eccentrically braced steel frames composited with high strength steel (HSS-EBFs) use ordinary steel (e. g. Q345 steel) for links and high strength steel (e. g. Q460 steel) for non-energy dissipation members. The usage of high strength steel effectively decreases the section size of structural members, reduces the construction cost and weakens the stiffness of the EBFs. This leads to the difference in the distribution of story shear force from that of ordinary EBFs. In this study, four HSS-EBFs of 5, 10, 15 and 20 layers were designed with ideal failure modes to study the elastic-plastic story shear force distribution of HSS-EBFs under rare earthquakes. Meanwhile, the velocity impulse from near-field and the cumulative effect of the seismic acceleration from far-field were considered. The nonlinear time-history method was used to calculate the response of HSS-EBFs under rare earthquakes. Based on the mean value of the elasto-plastic story shear force, a distribution pattern of elasto-plastic story shear force consistent with national codes and standards was proposed, which was found to have a higher level of accuracy compared with other existing distribution patterns. The results of the current analysis provide a reference for energy design method and plastic seismic design theory of HSS-EBFs.