Performance behavior of eccentrically braced steel frame under seismic loading

Abstract

Recent past growth of multi-story buildings structures with emphasis on steel has been found satisfactory. For solving the better-quality accommodation in the region where the chances of earthquakes are likely, role of bracing system enhances the performance of building under lateral load effect of earthquakes. Various methods of bracing systems are available in practices however, eccentrically braced frames (EBFs) are fairly new lateral force resisting system established to resist seismic event in a probable manner. Properly designed and detailed EBFs perform in a ductile manner through shear or flexural yielding of link element. The ductile yielding indicates wide hysteresis loop, which is excellent energy dissipation essential for high seismic event. The seismic performance of multi-story steel frame is designed according to the Indian code (IS800:2007). A simple computer-based pushover analysis is a procedure for performance-based design of buildings subjected to earthquake loading. Pushover analysis gets much importance in the past due to its ease and efficiency of the results. In this study eight frames were taken,among these, six frames which were braced as V, Inverted V, and Diagonal and remaining two are frames without bracing in two alternate heights (4 and 8 story). Seismic response of frames is studied using non-linear static analysis (pushover analysis) in terms of base shear, roof displacement, spectral displacement, spectral acceleration and story drift.