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Parametric Study Of Self-centering Concentrically Braced Steel Frames Based On Frictional Energy Consumption

Posted on:2020-01-09Degree:MasterType:Thesis
Country:ChinaCandidate:B B HuFull Text:PDF
GTID:2392330590487174Subject:Architecture and civil engineering
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The traditional concentrically braced steel frame(CBF)structural systems have a limited lateral displacement capacity,so that the bracing will buckle and produce residual lateral displacement under strong earthquakes.In recent years,the self-centering concentrically braced steel frame(SC-CBF)has a good lateral displacement capability and a small residual lateral displacement under strong earthquakes.The significant difference between SC-CBF and traditional CBF is that: the SC-CBF column can be lifted from the foundation under the lateral load,so that the frame will experience a rigid body rotation,and the vertical prestressing tendons can provide a restoring force to return the SC-CBF column to the initial position,the friction member set between the SC-CBF column and the gravity column can generate friction under the action of the horizontal inertial force to prevent the SC-CBF column from uplifting,and dissipates earthquake energy under the cyclic load.In this paper,the basic mechanical properties of SC-CBF structures under the lateral load are discussed firstly.According to the structural performance level and the performance objective,the performance-based seismic design method of SC-CBF is given.Next,use the performance-based seismic design method to design and calculate the SC-CBF prototype structures.Previous studies have determined that the geometry of the frame and friction coefficient of the friction device are the key design parameters for SC-CBF design.Three SC-CBF structures with different spans and three SC-CBF structures with different frictional energy-dissipating devices were designed to investigate the influence of frame span variation and frictional force on the seismic performance of SC-CBF structure.Finally,the finite element modeling of SC-CBF structure was carried out by OpenSees.Through the nonlinear static analysis of SC-CBF structure models with three different spans and three different frictional energy dissipating devices,the influence of the frame span and frictional force was researched on the structural stiffness,component section size,energy dissipation capacity,lateral displacement capacity,and column decompression during prestressing tendon yielding.Meanwhile,by the nonlinear dynamic analysis of different SC-CBF structural models,and the effects of frame span and friction was investigated as well on the seismic performance of structural apex lateral displacement,prestressed tendon axial force,SC-CBF column gapopening response and rocking response.The results indicate that the frame span and friction have a significant effect on the seismic performance of self-centering concentrically braced steel frames.The larger the span of the frame is,the smaller the cross-sectional area of the prestressed tendons are.the smaller the top lateral displacement capacity of the prestressed tendons when yielding.The increase of the frame span will enhance the energy dissipation of the structure;at the same time,with the increase of the frame span,the peak response of the SC-CBF column gap opening increases,the amplitude of the structural sway response increases,and the yield probability of the prestressed tendon increases.In addition,the increase of frictional force will also reduce the cross-sectional area of the prestressed tendons,and the structural design will be more economical.The increase of friction will strengthen the energy dissipating capacity of the structure,and the peak response of the top lateral displacement and the peak response of the SC-CBF column gap opening will decrease,the overall sway response of the structure is reduced.
Keywords/Search Tags:self-centering concentrically braced steel frame, frame geometry, friction, OpenSees, nonlinear static analysis, nonlinear dynamic analysis
PDF Full Text Request
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