Study On The Mechanical Behavior Of Eccentric Buckling Restrained Braced Steel Frame With Replaceable Link

Eccentrically braced steel frame as the main structure of the high-rise steel structure buildings,the construction principle is "strong column,strong brace and weak link beam",aimed at the column,beam and brace of the eccentrically braced steel frame have sufficient strength,when the earthquake occurs,the inelastic deformation of the structure is concentrated on the link beam.It not only increase the lateral stiffness of the structure,but also dissipate the seismic energy.And improve the safety of the structure.But the drawbacks of this structural is link beam is a part of the frame beam,Which is not conducive to observe the damage of the frame members with small earthquakes,and after the big earthquake,inconvenient to repair and replace the damaged link beam,Increase the difficulty of structural repair.Based on the disadvantages of the traditional eccentrically braced steel frame system,the energy dissipation beam is separated from the frame beam,and the buckling restrained brace is introduced.An eccentric buckling restrained braced steel frame with replaceable link is formed.The advantages of this structure system is:(1)Through the change of the section size of the replaceable link,the inelastic deformation of the structure is concentrated on the replaceable link,to ensure that the other construction members are in the elastic state;(2)It is helpful to observe the damage degree of the structure after the earthquake and to evaluate the safety of the structure conveniently;(3)After the earthquake,the damaged link beam can be removed and replaced,which will reduce the maintenance cost.(4)The double-steel-tube buckling restrained restricting braces with contact-rings can enhance the strength of structure and dissipate earthquake energy.Firstly,numerical simulation of the eccentrically braced steel frame is carried out by using finite element software,and the mechanical properties of the replaceable link and the whole frame are analyzed.Then 4 specimens are selected to experimental research,the mechanical performance,energy dissipation performance and the substitutability of the replaceable link are verified.Through the analysis,the following conclusions can be obtained:(1)The inelastic deformation of the eccentric buckling restrained braced steel frame with replaceable link can be concentrated on the replaceable link,and replaceable link can play a role in passive energy dissipation,at the same time,it can effectively protect other components in the structure.(2)Replaceable link has better bearing capacity and good ductility,which can meet the requirements of the deformation under earthquake;the hysteretic curve is full,the replaceable link has good energy dissipation.But,stiffness degradation is obvious.(3)The introduction of the double steel tube buckling restrained brac es with the contact rings significantly improve the strength of the whole eccentrically braced steel frame.To ensure the inelastic deformation o f the beam at the same time to assist the beam dissipation seismic energy.(4)The "replaceability" of replaceable links is proved to be feasible by experiment.