Evaluation of seismic performance of steel frames with Y-shape braces under far-field and near-field earthquakes

In this study, at first, the finite element modeling of Y-shape bracing system is developed and verified. In the next, the seismic performance of steel frames with Y-shape braces under far-field and near-field earthquakes was evaluated. For this purpose, seismic analysis was performed under 12 seismic records of near-field and far-field on 4, 8, and 12-floor structures equipped with and without Y-shape bracing. A series of time history analyses were performed on the samples, which led to the precise review of the Y-shape bracing system. The results show that structures equipped with Y-shape braces have less lateral displacement and also less number and level of plastic hinges; and, the level of non-linear dissipated energy is higher in those structures. Also, the plastic hinges based on the failure indices of the structures indicate that the near-field earthquakes have a more destructive effect of about 20% higher than far earthquakes on structures equipped with Y-shape bracing. Y-shaped bracing has reduced the permanent displacement in the system up to 30%.