Study On Seismic Behavior And Damage Evolution Of RC Frame-core Wall Structures

In recent years, reinforced concrete frame-core walls are widly used in high-level andthe extra-high building. The theoretical analysis and design methods of core walls are fewintensive studied and seismic performance of this kind of structure is poor. Therefore, it isimportant theoretical and practical significance to study seismic performance of core walls.Combining the theory with experiments，this text deals with the study of deformation andenergy response by the means of nonlinear seismic response of struetures.Combining with performance grades of reinforced concrete structures at home andabroad, the seismic performance of reinforced concrete frame-core structures can beinduced into four levels: normal service, continual service, temporary service, life safetyand collapse prevention. Considering four seismic levels, the structure performanceobjectives and seismic fortification criteria are formed. The equations to calculate physicaldisplacement of shear wall specimens for different performance objectives werederived．Based on the statistical data of the experiments and results of reinforced concreteframe-core wall structures, quantization indexes of different performance levels offrame-core wall structures are put forward. According to analysis of the lateral deflectionsmodel and displacement component, the floor displacement is divided into physicalinter-story displacement and non-physical inter-story displacement, and three kind ofdifferent calculation methods were introduced. On the basis of utilizing the analyticalmethod, this paper investigates the characteristic of rotation angle at floor plan, inter-storydisplacement and physical inter-story displacement.The earthquake input energy spectrum of elastic and inelastic single degree offreedom (SDOF) system under a world-wide ensemble of earthquake records of differentsite types are studied. The influence parameters, including the parameters of the SDOFsystems and the ground motions, on the input energy spectrum are investigated. With the normalized input energy spectrummethod, the input energy spectrum is simplified into fourparts as a function of the vibration period of the SDOF systems,and the factors of the inputenergy spectrum are suggested. While for the inelastic MDOF system, the input energy canbe obtained on the basis of MPA method.Elastio-plastic dynamic analyses of9reinforced concrete frame-core wall structureswith different structural characteristics were carried out under several sets of groundmotions. The earthquake total input energy of the structure under ground motion, and theregularity of the total input energy between hysteretic energy and damping energy werediscussed; The relationship of hysteretic energy and structural characteristics, thedistribution of hysteretic energy among shear wall, coupling beams and frames werestudied, as well as the distribution of hysteretic energy along different stories. A calculationmethod of interlayer distribution of the hysteric energy which reflect the structural stiffnesseigenvalue, coupling beam and shear wall stiffness ratio is proposed with using parameteranalysis and regression fitting method.An improved two-parameter damage model which was applicable to reinforcedconcrete frame-core wall structures was proposed by considering the effect of deformationand accumulative hysteretic energy dissipation based on the analysis of existing earthquakedamage models, then the feasibility of the damage model was verified. The damage modes,seismic performance are studied through nonlinear pushover and dynamic analyses ofseveral RC frame-core wall structures with various parameters. A rational damage mode inRC frame-core wall structures is proposed.