Analysis Of Energy Dissipation In The Framework With Buckling-restrained Braces

Frame and braced frame structure is widely used in the high-rise building structure.The lateral stiffness of the pure frame structure is limited.In the earthquake and windloads, the lateral displacement is large.So the height of the frame is limited. Bracedframe structure can improve the lateral stiffness of the structure to a certain extent, but itis esay to buckling when compressed under strong earthquake.It extremely easy to causethe failure of the brace or the failure of the connection.At the same time the capacity ofhysteretic energy dissipation after the yield is reduced and difficult to consume energyeffectively.So the seismic capacity of structure comes down. The present developingbuckling-restrained brace effectively change the problems of general compressionbuckling.Based on the theoretical research and test, the author research the applicationand feasibility of buckling-restrained brace in practical engineering. This paper mainlydiscuss the following several aspects：1）Firstly,taking a nine storey frame structure in Xinxiang city of Henan province asan example, using finite element analysis software SAP2000, analyse the original framestructure, ordinary braced frame structure and buckling-restrained with modaldecomposition response spectrum analysis and time-history analysis,comparison of thethree with cycle, storey drift, base shear, axial force and so on, and draw the hystereticcurve in small earthquake, middle earthquake and strong earthquake.The results showthat, the properties of BRBs under small earthquake are basically the same with thecommon braced;under the middle and strong earthquakes, the BRBs began to enter theenergy dissipation, by means of the hysteretic consumes the earthquake energy, whichhas obvious damping effect. 2）After defining the advantage of buckling-restrained brace,taking a five storeyframe structure in Xi’an city as an example,calculate the lateral stiffness of the structurethrough the D value method, given the target displacement, according to the lateralstiffness ratio of braces and frames calculate the BRB’s area. And the author analyse theframe-work with a variety of layout scheme of buckling-restrained under rareearthquake by meand of static elasto-plastic analysis.And the author compare with thevarious schemes of the plastic hinge development and seismic response (cycle,displacement, base shear) obtained the best optimum layout scheme. Taking the two ofthese schemes as an example, through the base shear-vertex displacement curve,performance, inter-story displacement angle nappe process further explantbuckling-restrained brace having more adequate security reserves under rare earthquake.3）In discusses the layout optimization of buckling energy dissipation braces, takingan engineering change (fortification intensity increased once) as an example, in thepremise of the same original component section size and reinforcement, by the additionof buckling-restrained brace, obtains the seismic response under standard limits.it showsbuckling-restrained brace has a very good applicable value in seismic strengthening anddesign changing project.