Seismic Analysis Of An Overrun Frame-core Tube Structure And Beam-slab-column-wall Space Cooperative Nonlinear Simulation Study

Along with rapid economic and social development and the advancement of urbanization,China's urban and rural construction and urban landscape change with each passing day,high-rise and super-high-rise buildings are constantly emerging.As a result,the structural design problems and challenges faced by engineers gradually increase.Among them,the stress mechanism and analysis methods and strengthening measures of the over-limit structure still need to be further studied and improved.In this paper,combined with the engineering structure design of an over-limit high-rise building,discusses and studies the effect of the frame-tube structure beam plate column wall against the side,core tube dark column and the analysis method of the calculation of the length coefficient of skip-floor column,in an attempt to provide a reference for the structural theory research and similar engineering structure design.PKPM-SATWE and MIDAS Building were used to analyze the seismic performance of structures.The vibration mode decomposition response spectrum method and elastic time-history analysis method are used to analyze the elasticity of the main building which is under the condition of earthquake and wind loads.The seismic performance of shear walls and frame columns in different regions of the structure is verified by the objective of bending and shear elasticity.MIDAS Building software is used to analyze the elastic-plastic dynamic time-history of the building under the condition of rare earthquakes.The seismic design of the main building is reasonable and safe by comparing the overall response index of the structure and the seismic performance level requirements.In order to analyze the spatial cooperative working mechanism of beam,plate,column and wall of the main building,the nonlinear finite element simulation analysis of the fifth floor at the bottom of the main building is carried out by using the 3D virtual laminated element analysis method.Through the second floor elected typical cross section's floor slab reinforcement stress analysis,the results show that,in the process of structure under overall stress,the floor load-bearing mechanism near the core tube area changes from "T wing beam+on both sides of the tensile stress"mechanism into "T beam wing+compressive" on both sides of the stress mechanism with the increase of load.While the main girder floor away from the core tube presents "T beam wing+ on both sides of the floor tensile stress mechanism.It provides a theoretical basis for effectively strengthening the stress sensitive parts to enhance the overall resistance of the structure.The influence of dark column on bearing capacity of core cylinder was discussed.The model of having concealed column and that of not having concealed column are established by using virtual laminated element method for 3D entity degradation.Through the contrast analysis of two groups of model of shear wall stiffness degradation,shear distribution and steel bar stress analysis,the results show that setting concealed columns in shear wall can make raise the rigidity of the core tube structure after entering the elastic-plastic stage and make it bear more shear,to a certain extent,thus protecting the outside structure of the framework.It is suggested that when the long-span frame beam intersects the shear wall flat,concealed columns can be set at the intersection of the shear wall.Although it can improve the stability of shear wall and prevent local damage,the change of horizontal shear distribution between frame and core should be paid more attention.Two sets of comparative analysis models of the elastic and elastic-plastic skip-floor columns are established.MIDAS Gen is used to analyze the buckling of the whole structure of the skip-floor column and VFEAP used to analyze nonlinear finite element of elastic-plastic skip-floor column.Through the corresponding buckling load value or the limit load value,the effective length coefficient of skip-floor column is obtained respectively.By comparative analysis of two effective length coefficients,it can be found that the effective length coefficient of skip-floor column according to elastic-plasticity is greater.In order to ensure the safety of the structure design,it is suggested that the effective length coefficient of the skip-floor column should be calculated by considering the elastic-plastic properties of the material and determined by the nonlinear finite element analysis.