Study On Torsional Response Of Reinforced Concrete Frame-core Wall Structure

With the development of social economy and the improvement of people's living standard,People have increasingly high demands on the appearance and function of buildings.In order to meet the needs of multi-functional,multi-purpose and novel appearance towards the building,the appearance of irregular high-rise buildings is unavoidable.The problem of torsion couple is becoming more and more serious.The previous earthquake damage shows that the building,especially the irregular building,is likely to cause obvious torsional failure.The Chinese code JGJ 3-2010 controls the structural torsion effect with torsion period ratio and torsion displacement ratio together.However,another Chinese code,GB 50011-2010,controls the structural torsion effect with torsion displacement ratio only.In practical engineering,the torsion period ratio and torsion displacement ratio cannot always meet the requirements of the code at the same time.The frame-core wall structure is widely applied in high rise and super high rise building for the reason that it has large lateral stiffness,great space performance and enough space to use.However,because the inside tube provide a lot lateral stiffness and little torsional stiffness,the torsion period ratio of frame-core wall structure is always ultralimit.In this paper,the frame-core wall structure is taken as the research object,and the influence of period ratio on the torsional effect of frame-core wall structure is analyzed.The main contents are as follows:(1)This paper summarizes the domestic and foreign research results on the torsion effect of buildings and compares the discriminant criteria and control indexes of torsion irregular structure between domestic and foreign code.(2)In this paper,the factors causing torsional vibration is discussed,and the calculation method of torsional coupling in Chinese code is shown.By changing the cross-sectional dimension and plane arrangement of structural members,the frame-core wall structure with different period ratio is designed.Measures to control torsion period ratio is discussed from the perspective of seismic concept design through elastic analysis under frequent earthquake.(3)Based on the engineering project,two frame-core wall models are designed through YJK design software.The torsion displacement ratio and inter-story displacement angle of the two models are both less than the code limit,however,the torsion period ratio of the two models is overrun the code limit and not exceeding the code limit respectively.the constitutive models of seel and concrete material used in Perform3D are introduced.The beams,columns,shear walls nonlinear element model selection are described and The elastic-plastic model is made through Perform3D.(4)Based on the Perform3D,the uniform distribution load and triangular distribution load are used to run the static elastic-plastic analysis towards two models in X direction and Y direction respectively.the difference of inter-story displacement angle and inter-story torsional angle between two models under frequent earthquakes and rare earthquakes is compared.The change trend of torsional effect and the plastic development of the component when the structure is into nonlinear period are analysed.The seismic performance of two models under rare earthquakes is evaluated and the reasonableness and effectiveness to of torsion period ratio to control torsional effect is discussed.(5)Based on the Perform3D,the dynamic time history analysis method towards the two models under frequent earthquakes and rare earthquakes is carried out by selecting three sets of bi-directional seismic waves which meet the requirements of the code.The difference of Vertex horizontal displacement,inter-story displacement angle,inter-story torsional angle and storey shear force between two models under frequent earthquakes and rare earthquakes is compared.The change trend of torsional effect,Energy dissipation and the plastic development of the component when the structure is into nonlinear period are analysed.The seismic performance of two models under rare earthquakes is evaluated and the reasonableness and effectiveness to of torsion period ratio to control torsional effect is discussed.