Seismic Performance Analysis Of Self-Centering Steel Concentrically Braced Frames Based On Opensees

The frame structure,composed of beams and columns,is widely used in modern civil buildings and industrial buildings because of its light self-weight and good integrity.For the steel frame structure,the braced frame is a normal structure form,but the traditional steel braced frame usually experiences a large residual deformation under the action of earthquake;before the yield of the braces or the failure of the frame structure,the structure has a large stiffness,but after yielding,the stiffness of structure decreases obviously and deformation capacity becomes poorer.Aiming at these shortcomings of the traditional steel concentrically braced frame(CBF)structure,a self-centering steel concentrically braced frame(SC-CBF)has become a hot research interest in recent years.The traditional structure can become a new structure with self-centering ability by using a special energy dissipation component,adding prestressed tendons,supplementing dampers,or releasing the column base.These ways can effectively reduce the residual deformation generated in the earthquake and increase the lateral drift capacity of the structure so as to improve the seismic performance and ensure a higher safety of the structure.Based on this background,the seismic performance of SC-CBF was studied and the main contents are as followed:(1)Through pushover analysis using OpenSees,the four limit states were indentified in thich paper including frame column decompression,prestressed tendon yielding and so on,and the mechanical behavior characteristics of SC-CBF structures were investigated under the limit states.(2)According to the relevant seismic theories and studies at home and abroad,the performance-based seismic design method(PBSD)of SC-CBF was discussed.The seismic performance of a SC-CBF designed by this method was analyzed.(3)The static elasto-plastic analysis,low cyclic loading analysis and dynamic time history analysis were carried out by OpenSees on the SC-CBF to evaluate the seismic performance of the structure designed by PBSD.(4)The Parametric study was performed considering such factors as different stiffnesses of GAP,different cross-sectional areas and arrangements of prestressed tendon for SC-CBF,and then the influence of,the above parameters on the seismic performance of SC-CBF structure was systematically researched.The research results show that: compared with the CBF,the SC-CBF exhibits a great self-centering ability and a slight residual deformation after the earthquake;the base shear response of SC-CBF is also smaller than that of the CBF;when the parameters are changed,the overall stress mechanism of the structure should be considered;different configurations have great impact on the lateral drift capacity and self-centering ability of the structure.