Evaluating Overall Ductility Factor of Steel Frames with Viscoelastic Bracing System

Abstract

The primary aim of this study is to evaluate the overall ductility factor of ordinary moment steel frames with viscoelastic bracing system. Similar frames without viscoelastic bracing assessed and compared as well. Linear history analysis of two types with different number of stories and spans lengths is carried out using different earthquake records to determine the elements sizes for the pushover analysis. Pushover analysis has been performed after defining the elements sizes and assigning material nonlinearity to discrete hinge where plastic rotation occurs to beams and columns according to FEMA 356. Such analysis allows evaluating the ductility factor of each building of concern by using the yield and ultimate displacements obtained from the pushover curve. The results showed that the overall ductility factor decreases with increasing the number of stories for all buildings or when the bay length increased. Adding viscoelastic dampers increased the ductility factors for all buildings significantly.