Behavior Study Of Y-eccentrically Braced Steel Frames Under Cyclic Load Considering Length Changed Of Link Beam

The concept of eccentric bracing in seismic design of steel building frames has gained substantial acceptance in recent years. In many countries, Eccentrically Braced Frames (EBF) have been used in a number of major buildings. In comparison with conventional framing systems, EBFs meet two basic criteria of seismic design: high stiffness at working load levels and large ductility at rare overloads. The eccentrically braced steel frames (EBF) is a good seismic system which has developed in recent twenty years. Y style eccentrically braced steel frame studied is one of EBF which has some special characters and will be applied widely in the future.Y style eccentrically braced steel frame combines the strength and stiffness of eccentrically braced frames (EBFs) with the inelastic behavior and energy dissipation of moment-resisting frames , especially inelastic deformation of link absorbs seismic energy. It is a kind of refined resistant-lateral system . So, the analysis about response and collapse mechanism of Y style eccentrically braced steel frame under seismic loading are not only significant in theoretical aspect , but also important in practice .Based on the questions that elaborated , three 1:3-scale steel frame specimens are tested in this paper,included two scale Y style eccentrically braced steel frame and one scale K style eccentrically braced steel frame. Studied and compared with the resistant-lateral capability of these three eccentrically braced frames cycle loading .Analyzed the stiffness,strength,ductility and dissipation of frame ,etc .On the basis of the experimental research and analysis , the performance and validity of Y style eccentrically braced steel frame and K style eccentrically braced steel frame are evaluated and their design method and course is presented .Nonlinear analysis are conducted on Y style eccentrically braced steel frame with numerical technology in this paper ,discussed stress of frame under varial loading conditions .Moreover , furthermore calculation about link are carried out in this thesis , introduced achieved research , summarized the affect of link on whole capability in the first , the second , numerical calculation are proceeded on link with ANSYS: with the purpose of discussing yielding mode critical length of link , established sevean different specimens,and elaborated the affect of the changing on link based on achieved test researches .Some problem about this research that ought be studied were put forward in the end of this thesis .