Analysis Of Seismic Response Of Steel Reinforced Concrete Frame And Reinforced Concrete Core Hybrid Structures In High-Rise Buildings

The exterior frame and reinforced concrete core hybrid structures in high-risebuildings are rapidly developed in recent years, the hybrid structures are appliedespecially in China. There are different views on the performance of the hybridstructures at home and abroad. At present, research works had mainly focused on steelframe and reinforced concrete (RC) core hybrid structures, however, the hybridstructures adopted steel reinforced concrete (SRC) components are more used. For thedeformation and mechanical behavior of SRC-Frame and RC-core hybrid structures,some problems had studied such as parametric modeling, co-operation between frameand core, structural dynamic characteristics, plastic beams hinge property of SRCmembers of seismic response analysis and optimal design based on dynamicperformances in this dissertation.The 3-D finite element analysis models of SRC-Frame and RC-core hybridstructures are built, in which beams and columns are simulated by three nodesTimoshenko space beam element, shear wall and floor are simulated by eight nodescurved shell element, the parametric modeling approach are made by means of APDLlanguage of ANSYS software. The effect of rigid character value to deformation, shearand moment distribution between core and exterior frame are analyzed. Shear lag inexterior frame would weaken the role of exterior frame resisting moment. The impactof connection between frame and core, floor thickness and steel rate with SRCcolumns in hybrid structures to co-operation performance are discussed, someconclusions can be for reference in hybrid structure conceptual design.The dynamic characteristics of SRC-Frame and RC-core hybrid structures areresearched through modal analysis, considered the connection between frame and core, floor thickness and steel rate with SRC columns, natural vibration periods and modeshape of hybrid structures had calculated and studied. The natural vibration frequenciesare near, while the response spectrum method are adopted, the complete quadraticcombination (CQC) modal combination rule is recommended for avoiding higher ordermode shape lose, truncation error analysis show that more than 20 modes arereasonable to mode combination.The mechanical behaviors of hybrid structures under frequently earthquake arestudied by means of response spectrum method and elastic time-history analysis. Theresults indicate that inter-story displacement maximal angle occurs on the middlestories of hybrid structure, there are two extreme regions of story acceleration alongthe height direction of the structure under earthquake. The connection between frameand core will lead to significant change in the deformation and distribution of internalforce. If there are rigid connection between frame and core, axial forces of framecolumn are increased significantly, on the other hand, shear and bend moment of framecolumn are larger when hinge connection. The advice what hybrid structures arerespectively analyzed in term with rigid and hinge modal were proposed in order toavoid overturning. And further, the effect of floor thickness and steel rate with SRCcolumns in hybrid structures to seismic response are explored. The variation regularityof displacement and inner force of hybrid structures were studied under frequently andrare earthquake, failure pattern with different connection were discussed.In Push-over analysis of hybrid structures, some methods for defining themoment-curvature curve of plastic beams hinge property and transformingmoment-rotation relationship are put forward based on beating capacity anddeformation of SRC member, means for determining the moment-axial forcerelationship of SRC columns hinge are brought. Three vertical truss element model areapplied to simulate shear wall, in which axial, shear and bend deformations areconsidered, then measures for defining axial stiffness of tension compression truss andshear stiffness are given, furthermore, the feasibility of these methods are verifiedaccording to two model experiment results.The core wall thicknesses are chosen by means of structure optimization design,the objective function about core volume is adopted, some specification requirementsabout deformation, the ratio of lateral stiffness to gravity, storey shear to gravity, storeyshear of exterior frame, axial compression ratio of column and wall limb, bearingcapacity of structural member and core construction are regarded as restrictingconditions, the optimal mathematical model is established for reflecting integrity dynamic properties of hybrid structure. Some analysis files of APDL language werewritten. Then an example of hybrid structures optimization is provided throughdifferent initial values for verifying convergence of optimization method.