Seismic Behavior Of Reduce Beam D-Type Eccentrically Braced Frames

Traditional D-type eccentrically braced steel frame use of bracing members to provide lateral stiffness under frequent earthquake,the link beam of D-type eccentrically braced steel frame sustain large inelastic deformation without loss of strength under serve earthquake to consume the energy occurred by earthquake in order to protect the main structure of the building.In recent years the eccentrically braced steel frame has been widely used in high intensity earthquake region and exhibit good seismic performance.In practical engineering applications D-type eccentrically braced beams often occur beam-column flange weld crack and premature structural damage due to excessive stress of beam-column welded connection.In past few years the domestic and foreign study on D-type eccentrically braced steel frame mainly focused on structure performance、mechanical characteristics、 failure characteristics。Those scholars have proposed many ways to improve the joint behavior of D-type eccentrically braced steel frame such as haunched beam、cover-plate between shear links and column、side-plate between shear links and column and so on。In order to improve the structure performance of traditional D-type eccentrically braced steel frame a new connection between link and column is proposed in this paper,the beam-column connection has been reinforced by reducing the flange of the link beam. By weakening the beam section properly,we can keep the plastic hinge away from the joint core and avoid flange weld crack and premature structural damage.In this paper,the experiments of traditional D-type eccentrically braced steel frame and reduce beam D-type eccentrically braced steel frame were simulated by ANSYS15.0,we can receive stress nephogram 、hysteresis curves、skeleton curves,、stiffness degradation curve 、failure capacity and yield capacity by studying the failure mechanism and seismic performance of the two type of eccentrically braced steel frame under cyclic loading.Through those results can prove that by reducing the flange of the link beam we can effectively transferred the plastic hinge from beam-column connection to link beam、improve the ductility factors and energy consumption coefficients.On the basis of the finite element studies,we conduct research on reduce beam D-type eccentrically braced steel frame by changing the relevant parameters in order to define howthose parameters such as the length of link beam(e)、the depth of reduce(a)、the distance of reduce point to column(b)、the length of reduce part(c)、the set up of stiffeners(s) influence the seismic performance of the reduce beam eccentrically braced steel frame under cyclic loading.By those finite element analysis of structure,we can obtain some suggestions that important to design and construction the reduce beam eccentrically braced steel frame.