Based On The Different Layout Of BRB-study On The Impact Of Seismic Performance Of High-rise Steel Structures

It is based on the Buckling-Restrained Braces(BRB)has good energy dissipation and shock absorption,and considering that the different layout of BRB is one of the factors that affecting the seismic performance of the Buckling-Restrained Braced Frames(BRBF).In order to study BRB,the large-span reticulated shell,the horizontal sharing rate,the combination of BRBF and RC frames,the arrangement of multi-layer steel frame BRBF,and the analysis of BRB under the pseudo-static cyclic load test are mainly studied by domestic and foreign researchers.However,there are few reports on the comparative analysis of the different layout forms of the high-rise steel frame BRB,as well as the reasonable layout and the better layout of the high-rise steel frame BRB.Therefore,with the first floor shear weight ratio C_B,strong column factorα_iand different arrangement forms of BRB as the main research parameters,the second-order nonlinear CLAP software modeling is adopted in this paper.The static pushover analysis and dynamic elastic-plastic time-history analysis of 7 high-rise steel structures with 6 spans and 20 floors were carried out.Considering the P-Δeffect of high-rise buildings is obvious,the relationship between interstory displacement and shear force of structure,the time sequence of plastic hinge forming hinge,the elastic-plastic energy,residual deformation,energy consumption ratio etc.under different BRB arrangements are studied,which can provide theoretical reference and guiding basis for the arrangement form of high-rise steel frame BRB in the future practical engineering.The results are as follows:Pushover analysis:(1)Regardless of whether P-Δeffect is considered or not,the failure order of beams in each layer of pure steel frame M1 is as follows:the outermost beam end of side-span beams is damaged first than other beam ends of the same layer.(2)From the component analysis,all the BRBs in the M2-M7 models yield,and all the BRBs yield is earlier than the beam end and column end,indicating that the BRB plays a good role in the seismic defense line.(3)The hinge forming sequence of plastic hinges is as follows:BRB yielding→the structure reaches the limit of elastic inter-layer displacement Angle 1/250→the end of beam yielding→the end of column yielding→the structure reaches the limit of inter-layer displacement Angle 1/50;(4)From the analysis of the elastic-plastic ultimate bearing capacity and the initial stiffness of the first floor,the model M5 has good lateral stiffness due to the staggered arrangement of BRB,and the elastic-plastic ultimate bearing capacity and the initial stiffness of the first floor of M5 are the largest.Dynamic elastic-plastic time-history analysis:(1)From the analysis of story shear force and story displacement,the order of maximum story shear force of three kinds of seismic waves is:Kobe-ns<HNS<San-ew;under the action of HNS and San-ew seismic waves,the influence of the first mode is dominant;under the Kobe-ns seismic wave,each model is obviously affected by the second mode;(2)The model M2-M7 has a small amount of beam member participation,while the pure steel frame M1 has a large amount of participation,so the bottom shear of model M1 is larger;The results show that the influence of beam end of each model is very small,and the energy absorbed by BRB is M5>M7>M6>M2>M3>M4,that is,staggered arrangement>inverted V-shape>large V-shape>central span>arrangement of the second and fifth spans>side span>pure frame;It shows that the staggered arrangement of model M5 is the best.(3)In the residual deformation,the residual deformation of model M1 is larger under the action of three kinds of seismic waves,and reaches the maximum in the middle layer,while the residual deformation of model M2-M7has less influence,and the residual deformation of model M5 is the smallest.