| Traditional eccentrically buckling restrained braced steel frame often integrate energy-dissipating beams with frame beams,and sometimes the amount of steel is increased by increasing the cross-sections of beams,columns and the brace to meet the structural design requirements,and the integrated design form of links makes it difficult to assess damage and to repair the structure after an earthquake.In view of the above problems,by separating the shear energy dissipating beam section from the frame beam for separate design and use double channel steel as the section of the energy dissipating beam section to concentrate the plastic deformation of the structure on the replaceable double channel steel energy dissipating link which provides convenience for replacement and repair after the earthquake,while also reducing the amount of steel used,making the structure more economical and reasonable.At the same time,the buckling restrained brace is introduced to form the eccentrically buckling restrained braced steel frame with replaceable double channel shear energy dissipation links.The introduction of buckling restrained brace can provide sufficient lateral stiffness,provide a second seismic line of defense,and improve the seismic performance of the whole structure.As important theoretical bases and key factor of performance-based seismic design theory,the rationality of structural influence coefficient,displacement amplification factor and over-strength coefficient has a profound impact on the development and improvement of existing structural seismic design theory and the improvement of safety and economy of seismic design,whereas in Code for Seismic Design of Building,the reduction method of seismic action of steel structure system is still the same as that of concrete structure,which makes the advantages of steel structure unable to play.Although the " General Rule for Performance-based Aseismic Design of Buildings " gives the recommended value of the structural influence coefficient of the eccentrically braced steel frame structure,the impact of the relevant parameters changes of the details of the energy dissipating link on the value of the structural influence coefficient is not considered.The parameters of the shear link in the eccentrically buckling restrained braced steel frame with replaceable double channel shear energy dissipation links are important factors that affect the seismic performance of the structure.Therefore,it is necessary to make a systematic study on the influence of the parameters of energy dissipation link on the structure influence coefficient.In this paper,the influences of the changes in the section size,the length and the number of stiffeners of the energy dissipation link and the height of the structure in the eccentrically buckling restrained braced steel frame with replaceable double channel shear energy dissipation links on structural influence coefficient R,displacement amplification factor Cd and over-strength coefficient RΩ was studied.The main work carried out is as follows:(1)According to current relevant codes,36 eccentrically buckling restrained braced steel frame with replaceable double channel shear energy dissipation links are designed according to different parameters of shear energy dissipation links and structural layer heights.The models are used for pushover and incremental dynamic analysis(IDA)to study R、Cd and RΩ.(2)A representative structure with a certain parameter is selected to carry out the pushover test and shaking table dynamic response research on the scale model of the one,three and five-story structure.The response,stress characteristics,failure mode and performance curve of the structure under earthquake action are studied,and the seismic performance of the structure is evaluated.The scaled finite element model was established to carry out Pushover analysis and IDA analysis respectively and compare the test results,which verified the rationality of the finite element model.(3)According to the capacity spectrum method that considers the influence of high-order mode shapes,the Pushover method and IDA method are used to solve the structural influence coefficient R,displacement amplification fector Cd and structural overstrength coefficient RΩ of all models through OpenSees finite element analysis software.Compare the influence of different parameter changes on the three performance coefficients,and the results of the two methods are compared.The results show that the changes in the parameters obtained by the two analysis methods have similar effects on the performance.By rationally designing the structural parameters of the energy-dissipating link,the seismic capacity and deformation capacity of the eccentrically buckling restrained braced steel frame with replaceable double channel shear energy dissipation links can be improved.It provides a reference for the research on the influence coefficient of eccentrically braced steel frame structure. |
PDF Full Text Request