Seismic Performance And Design Of Self-centering Steel Reinforced Concrete Wall Panels With Energy Dissipation Devices In Steel Moment Frames

Nowadays,one of the new requirements for earthquake resistance of engineering structures is to realize the rapid recovery of normal functions of engineering structures,cities and even the whole society after strong earthquakes.It is an important means to design and construct a new earthquake resistant structure with recoverable function.For purpose of reducing maximum deformation of steel frame in the epicenter and residual deformation of steel frame after the earthquake,a new steel frame-self-centering steel reinforced concrete wall panel with replaceable energy dissipation devices(SF-SSW structure)was proposed.The novel structure was aimed on the cooperative performance of the connection between wall panel and steel frame,combined with the new energy dissipation components and the self-centering post-tensioning control technology.The experimental investigation and theoretical analysis on seismic performance,calculation theory and design method of SF-SSW structure were carried out in this paper.The research is as follows:1.Development of SF-SSW sub-structure and experimental study on full scale specimensThe cyclic tests on six full scale self-centering wall panels were performed.The tests studied steel frame,self-centering panel and the force characteristic,failure modes,bearing capacity,stiffness degradation,hysteretic response and energy dissipation of energy dissipation device.The results revealed that every specimen performed similar force characteristic,and showed great self-centering performance and excellent energy dissipation capacity with controllable residual deformation.The force mechanism of the structure expressed three typical stages: the wall started to rotated;energy dissipation plate yielded;the tensioning of prestressed tendon and the bearing capacity was improved continuously.It provided experimental evidence for the determination of quantitative values of performance indicators,the establishment of restoring model,the nonlinear analysis and the method of seismic design.2.Analysis on effect factors of mechanical behavior for the SF-SSW structure through accurate and reasonable nonlinear finite element modelFinite element model of SF-SSW substructure was established by using ABAQUS software,and the nonlinear numeric simulation on variable parameter analysis were carried out.(1)Geometric parameters and initial prestress of post-tensioning strands are important factors affecting the mechanical performance of structures.The increased diameter of post-tensioning tendon could significantly improve initial stiffness and bearing capacity of the structure.The initial stiffness and bearing capacity of the structure is slightly influenced by increasing initial prestress of posit-tensioning tendons,but it will weaken the energy dissipation capacity.(2)The geometric parameters of the energy dissipation plate have the greatest influence on the energy dissipation capacity of the structure.The thickness of devices plates increase one times,the structural initial stiffness and bearing capacity,also the energy dissipation performance is increased by 30%,40% and 90%.In contrast,the self-centering performance was reduced by 80%.(3)The width of the wall panel and the cross-section size of the steel beam have great influence on the mechanical properties of the structure.When the width of the wall plate is increased by 50%,the initial stiffness and bearing capacity of the structure are increased by 200% and 150%,and the energy dissipation capacity and self-centering performance are reduced by 40% and 10%.With the section size of steel beam increased,the self-centering capacity,initial stiffness and bearing capacity of the structures have been improved.3.Establishment of computational theory for the SF-SSW structureThe calculation method including the in-plane lateral stiffness of SRC wall panel structure was studied.Based on simplified analysis models,the formulas for calculating structural lateral stiffness that considering constraint deformation of the frame beams and the overturning deformation of wall panels were derived.The developed analysis models and calculation diagrams of each stress stage based on the typical three-stage failure characteristics of structural system,and the formula of shear capacity was established.Combining with the test results of the structural system,the skeleton curve of structure was determined.According to developed intensity ratio coefficient β,the related equations on important parameters affecting the models were derived.Besides,the loading and unloading rules of hysteretic models were determined.Finally,the restoring model of SRC wall panel was proposed,which provided the reference for seismic design.4.Seismic response analysis of multi-layer SF-SSW structure systemThe simplified analysis models of the structural system were developed,the pushover analysis and dynamic analysis on multi-story and high-rise steel frame structure and new structural system under the same conditions were carried out.The SF-SSW structure has experienced the plastic development process from devices yielding to the beam ends yielding,and finally the plastic hinges appear on both beam-column connection.At the same time,the target displacement of SF-SSW structure under rare earthquake was obtained by using improved capacity spectrum method.The result revealed that the structural capability curve intersected with the elastic-plastic demand spectrum of rare earthquake and moderate earthquake under action of different earthquakes.Furthermore,the maximum inter-storey displacement angle of the structure was lower than the limit value of specification,which meets the demand of seismic performance under large earthquake.It is noted that the structure occurred to automatic restoration obviously after earthquake,with the residual deformation greatly reduced.And the self-centering wall-panel structure greatly relieved the plastic development of main bearing members,the structural system obtained superior seismic performance.Therefore,the novel structure can realize the performance-based design goal of “without repair after middle earthquake,protect life and property safety during great earthquake,and repair quickly after great earthquake”.5.Study on performance-based seismic design method of SF-SSW structure systemOn the basis of existing seismic design method and the theoretical analysis of steel-composite structures,the direct displacement-based seismic design method of SF-SSW structure was proposed using the performance target,and then the proposed design method was verified.Generally,it is proved that the new type of self-centering wall panel with replaceable energy dissipation devices in steel frames(SF-SSW system)is feasible and reasonable,the research results provide the test basis and theoretical guidance for real projects.Finally,some issues that need further investigations are discussed.