Two Order Analysis Of Frame Core Tube Structure With Strengthened Stories

The frame-core tube structure system consisting of the peripheral frame and the central inner tube has become a widely used structural system in high-rise buildings in China.In order to improve the lateral stiffness of the pure frame core tube and reduce the lateral displacement of the structure,a frame-core tube structure with a strengthening layer is formed by setting a strengthening layer on the structure.Due to high reasons,the stress state of this high-rise and super high-rise building is very complicated.Because the structure is subjected to horizontal and vertical loads,the lateral displacement of the structure will increase,and the internal components of the structure will produce additional internal forces.Under the influence of P-delta effect,the structure will weaken the bearing capacity of the structure and affect the overall stability of the structure.On this basis,the second-order analysis of high-rise structure with reinforced story frame core tube is of great significance.In order to further supplement and improve the two level analysis of structure,the paper mainly studies the following aspects:Firstly,on the basis of the basic structure and mechanical properties,the frame-core tube structure with strengthened story is regarded as Timoshenko beam under combined compression and bending,and the restraint effect of the strengthened story and the outer frame column on the core tube is simplified as bending spring.Then the Hamiltonian dual solution system is introduced and the boundary conditions are substituted.The finite element method based on precise integration displacement is programmed by MATLAB to obtain the internal force and deformation of the structure.Finally,the two order analysis results of a reinforced concrete core tube structure with strengthened stories are compared.Taking an engineering example as the background,the numerical simulation of the engineering example is carried out by using the ETABS finite element software,and the effect of the second-order effect on the lateral displacement of the structure under different loads is considered.The results of the finite element method based on precise integration are compared with those of the ETABS finite element analysis software,so as to design the structure.The feasibility of simplified modeling method is verified by reference.Through comparative analysis,this paper believes that in the preliminary design of the structure,the simplified modeling method proposed in this paper can be used to estimate the building,and provide a check measure for the overall modeling analysis in the final stage of the design.