INCREASED DUCTILITY OF STEEL STRUCTURE FRAMES WITH ARRANGEMENT OF ECCENTRIC BRACES AND RESISTANT TO BUCKLING UNDER SEISMIC LOAD

Abstract

One of the goals of seismic design of structure is to control damage to structure in severe earthquakes. Changing the outlook of seismic regulations from increase of the resistance of structure to increase of structure ductility reveals the necessity to attention to seismic assessment of structure regarding the outlook of ductility capacity (Ductility capacity). Due to the fact that the bracing change in height of the structure is less of interest to researchers and structural engineers, most of studies have centered on the brace changes in the structure plan and the braces are used without change in the height, thus study on increased ductility of steel structure frames with arrangement of eccentric braces and resistant to buckling under seismic load has been taken into consideration in this study. If it can improve seismic behavior of the brace by changing the type of brace in the height of structure, it can insure about the seismic function of the brace. Further, it can take action to optimize consumption of steel materials in metal buildings. For this, a number of eccentric braced steel moment frames with different number of storeys(6, 9 and 12 storeys)were undergone the nonlinear dynamic time history analysis after loading and designing based on Iranian standards, under 7 earthquake records including the near-fault earthquake record, and seismic damage to these frames were examined by changing type of bracing in Various height balances of these frames.