Research On Structural Design And Hysteretic Behavior Of End-Plate Connected Replaceable Shear Links For Eccentrically Braced Steel Frames

In order to improve the lateral stiffness of the structure, eccentrically braced steel frame structure system has widely used in various kinds of high-rise buildings. The shear links is the main dissipative member in the eccentrically braced steel frame structure. But in the traditional design, the link is part of the floor beam, as a result, the repair and replacement of the link can be very difficult and costly after a major earthquake. Based on improving the design defect of the above mentioned traditional eccentrically braced steel frame structure, This paper proposed a new type eccentrically braced structural system in which a replaceable shear link specimen was connected to floor beam by end-plate. Because the inelastic deformation will be concentrated only within the link, damaged links can be quickly inspected and replaced following a major earthquake.Furthermore, the use of replaceable links allows for the welding of critical elements, such as the brace connections, to be performed in the shop, considerably reducing erection time.The force analysis of the new type eccentrically braced structural system bearing horizontal load has been finished in this paper so as to study the design calculating methods of the new-type structural system by a specific example.The finite element model of a one-story eccentrically braced steel frame with an end-plate connected replaceable link specimen was established by software ABAQUS.The key issues in the process of modeling,such as plastic flow rule,interaction, failure criterion,was introduced detailedly.The whole stressing process of the primary member in the new system was simulated, the numerical results showed that the inelastic deformation is concentrated only in the link which verifies the "replaceability" of the shear link in the new-type structural system.Furthermore,the finite element model of a traditional eccentrically braced steel frame was also established by software ABAQUS,and its size is same as the new-type structural system’s(except of the shear link’s size).The differences of hysteretic behavior between the new-type and the traditional system under the same cyclic loading was compared. The results showed that the energy-dissipating capacity of the new and traditional system was basically the same.The ductility and link’s plastic rotation capacity of the new system was larger than the traditional systen’s,and the speed of stiffness deterioration of the new system was slower than the traditional system’s,but the new system’s ultimate bearing capacity was lower than the traditional system’s.Finally,a series of parametic finite element analyses were executed in order to analyze the factor of link’s length,thickness of link’s web and distance of link’s rib to be changed affect hysteretic behavior of the new-type structural system.The results showed that during the increase of the link’s length,the energy-dissipating capacity and link’s plastic rotation capacity of the new system was descending obviously,and the ductility and ultimate bearing capacity decrease by degrees, the speed of stiffness deterioration increased gradually; during the increase of the thickness of link’s web, the energy-dissipating capacity and ultimate bearing capacity of the new system was increasing obviously,and the ductility and link’s plastic rotation capacity increase by degrees, the speed of stiffness deterioration decreased gradually; during the increase of the distance of link’s rib,the ductility of the new system falling slowly,but the change of the energy-dissipating capacity, ultimate bearing capacity, link’s plastic rotation capacity,and the speed of stiffness deterioration was not very obvious.