The Research On The Seismic Performance Of Mega Steel Frame With Buckling Restrained Brace

Since entering twenty-first Century,China’s economic and technological development into the golden period.With the rapid development of China’s economy and the rapid increase in population,people’s life style and working way change,make people to the requirement of high rise building.But the development of the giant steel frame style is more and more diverse,the structure layer is more and more high,the structure is more and more complex,so the giant steel structure is more and more popular.Although the mega steel frame structures have good ductility,the lateral stiffness of the structure is relatively small.Under the action of earthquake load,the horizontal displacement of the structure is large,and the mega steel frame supporting members must provide a large lateral stiffness for the structure.When the earthquake intensity is very large,the axial force will be very large,it is prone to damage and instability,therefore,the choice of anti side force component,become a giant steel frame structure design of the weight.In recent decades,experts and scholars at home and abroad have a lot of research on the energy dissipation and shock absorption,and have achieved fruitful research results.The earthquake resistance of buildings is no longer just the rigidity of the beam column,but the use of the structure to reduce the damage to the building.In the traditional sense,the mega steel frame design,the application of the most is the general support of the structure of the lateral axis force.Although the general support constraint is small in elastic stage,the stiffness is large,but under the lateral load,the bearing capacity of the structure is easy to be loaded under the normal support.In order to overcome the common support compression to yield shortcomings,experts and scholars at home and abroad were studied,and finally found the buckling restrained brace can not only makes the structure under seismic loads can yield and buckling.The buckling restrained brace is also called BRB,which can reach the yield without buckling failure in tension and compression.Buckling constraints are generally composed of three parts,that is,the core element(core material),the constraint unit and the material composition of the material between the drug and the constraint unit.The core element is main stress components and by the low strength steel,common is in the shape of a cross and a grapheme;and constraint element to provide lateral confinement,prevent the compression of the core material when buckling,at present commonly used for concrete filled steel tubular(CFST);no adhesive material warehouse is wrapped on the surface of the core unit for eliminating the friction between the core unit and the constraint element.For buckling restrained braces.Firstly,this paper on the basic working principle are introduced,then the design parameters in the process were analyzed.Finally,the whole model is established by analysis.In this paper,the SAP2000 structure analysis software is used to establish the model,which includes the general support and the buckling restrained braces.The model considers the characteristics of the material nonlinearity and geometric nonlinearity.Firstly,two kinds of modal analysis are carried out to obtain the basic dynamic characteristics of the structure.Then the model and model 2 frequent earthquake vibration mode analysis and elastic process analysis,to determine their inter layer displacement,story displacement and story shear,and the two models in frequently occurred earthquake,seismic response of comparative analysis.In the end,two kinds of model structures were analyzed by SAP2000 software,and the seismic performance of the model was analyzed.Results show that the buckling constraint support can effectively reduce the lateral displacement of the structure,is acting as a first line of defense,that anti seismic effect of buckling restrained brace is much higher than ordinary support the conclusion.