Seismic Vulnerability Analysis Of High-rise Steel Reinforced Concrete Frame-reinforced Concrete Core Tube Structure Hybrid Construction

With the increasing of modern building height,the steel-concrete hybrid structure has been applied more and more widely.However,the study on the seismic behavior of steel-concrete hybrid is not fully studied.In this paper,a numerical simulation and theoretical analysis method is applied to a 30 story steel reinforced concrete(SRC)frame-reinforced concrete(RC)core tube structure.The seismic performance and seismic fragility of the structure are analyzed.The main contents of the article are as follows:Firstly,The feasibility of fiber beam column element model for analysis of simply supported beam members is verified,with using MIDAS/GEN finite element analysis software.Establish the finite element model of SRC frame-RC core tube structure.the steel reinforced concrete frame column used fiber beam column element.The steel beam used three-dimensional beam element.And the shear wall used 3D shear walls macro element.All of these provide in MIDAS/GEN software.MIDAS/GEN(finite element analysis)software is used to analyze the structure by static elasto-plastic analysis(PUSHOVER).The seismic performance level and the corresponding limit state of the typical model are divided.The maximum interlayer displacement angle is used as the quantitative index of the different performance of the structure,and the limit value of the quantization index is determined.The PUSHOVER method is used to obtain the capacity spectrum curve,the seismic demand spectrum curve and the performance control points.According to the data obtained by finite element analysis,the vulnerability analysis of the structure is carried out.Change the stiffness of the external SRC frame and the stiffness of the inner RC core tube to obtain 9 calculation models.Based on the analysis of the vulnerability of 9 hybrid structural models,the fragility curves of the structures under different stiffness systems are established.The probability curves of 9 different limit states are plotted in the same coordinate system.The exceedance probability of each limit state decreases with the increase of the structural stiffness.The change of the external frame size relative to the change of the core shear wall has a great influence on the stiffness characteristic value,the probability of exceedance is more obvious,and the safe probability of the whole structure tends to be more obvious.4 calculation models are obtained by changing the structural floor live load to change the axial compression ratio of the shear wall.The probability curves of 4 different limit states are plotted in the same coordinate system.The influence of axial compression ratio on the vulnerability of structures is more and more obvious in the process of structural risk.With the increase of the axial compression ratio,the safe probability of the whole structure tends to be reduced,and the probability of approaching danger increases.Structural vulnerability increases gradually.