Anti-seismic Optimized Design Of Buckling-restrained Braced Steel Frame Structure

Frames-brace is a kind of double lateral force structure system. It has twolateral force lines. One defense is the brace part, the other is the frame part. It iswidely used in the steel structures for its good resist lateral stiffness and seismicperformance. But it loses stability easily when it is in press because of its largerslenderness ratio of its traditional brace. It can not display fine resist lateralperformance especially in the action of the seismic loads.The buckling restrained brace improves the traditional brace. It not onlyovercomes the shortcoming of easy buckling when brace is in the pressure butalso can achieve total cross-section yield when brace is in pressure or in tension.It has good hysteretic performance. It can consume large amounts of theearthquake energy in the action of the earthquake loads so that it can effectivelyprotect the safety of the structure.The research on the design theory of single prevent buckling support hasmatured at present. And it has been widely used in the practical engineering inabroad especially in Japan and the United States. In China the existing researchesare mainly on single component. The research on the design of bucklingrestrained brace is relatively less. The latest researches mainly design thisstructure system separately according to resist lateral stiffness ratio of the braceand frame. The research checks structure system through modal analysis,vibration mode decomposition spectrum analysis, dynamic history analysis andpushover analysis. The research makes the storey displacement of this systemmeet the standard requirement through adjusting the size of the structure andother parameters. However, the existing researches usually make the frame strongso that the structure can meet the standard requirement easily. The research onhow to adjust the structure system which can not meet the standard requirement isrelatively less, and this text make this topic research for the shortage. We usually design the structure system according to the resist lateral stiffnessratio of the brace and frame. When the preliminary design of structure system cannot meet the standard requirement, we adjust the whole structure system. Weadjust the frame part first, and then we adjust the brace part according to thelateral stiffness ratio. We can make the structure system meet the standardrequirement by constant adjustment. This kind of adjustment is quite tedious andthe efficiency is low. When using buckling restrained brace to strengthen theexisting frame structure, we can only adjust the brace part`to make it meet thestandard requirement. But the designers can only increase the section size withtentative. They make the structure system meet the standard requirement byconstant adjustment.But the workships are very hard and more tediously.In this text, we have based on the requirement that the share rate of Shear ismore than25%in the frame of dual structure systems. We design the structuresystem after the share rate of interlayer shear forces of the steel framework andbrace has been made. We make dynamic history analysis to the structure systempreliminary designed using the finite element software ABAQUS. And we studiedhow to adjust the frames-brace whose layer displacement can not meet thenational standard requirement and put forward the promotion of methods whichcan adjust the structure system and the optimizing parameter. It can providereference for designers.