Basic Mechanics Analysis And Seismic Performance Research Of High-rise Diagrid Structures

High-rise diagrid structure is a lateral force resistant structure system composed of diagonal columns.High-rise diagrid structure can be divided into two types:high-rise diagrid tube structure and high-rise diagrid tube hybrid structure composed of diagrid outer tube and shear wall core tube.As a new structural system,it integrates vertical bearing and lateral force resisting structure.It has many advantages,such as high lateral stiffness,internal force transfer by tension and compression,and high material utilization rate.However,the theoretical research and seismic performance research of high-rise diagrid structures are still in the initial stage.In this paper,the elastic calculation method,mechanical properties,section optimization,system stability analysis,elastic-plastic seismic response and seismic vulnerability evaluation of high-rise diagrid structures are studied.The following research work has been carried out specifically:On the basis of theoretical analysis of high-rise diagrid tube structure,the simplified mechanical model of the structure is established,and the calculation formulas of its internal force and lateral displacement are derived.The internal force distribution and shear-lag effect of high-rise diagrid tube structure are analyzed,and the method for determining the optimal angle of diagonal column is put forward.The analytical expression of shear lag coefficient of structural system is given,The shear lag coefficient at the maximum shear lag position and bottom of the structure is numerically simplified.The relationship between height-width ratio,angle of diagonal column and shear lag coefficient of structure is obtained.The analytical expressions of the relationship between the optimal angle and height-width ratio of diagonal columns under different horizontal loads are given.The shear deformation coefficient of high-rise diagrid tube structure is defined,The ratio of shear deformation to total deformation of structure is studied quantitatively.The elastic-plastic cooperative working mechanism of shear wall with diagrid tube and core tube in high-rise diagrid tube hybrid structure is studied.The factors affecting the cooperative work of different lateral force resisting members are studied.The distribution characteristics of structural shear force are analyzed,and the selection principles and influencing factors of optimal thickness of shear wall and optimal cross-sectional area of diagonal column are studied by mathematical optimization method.The elastic buckling and global stability of high-rise diagrid structure system are studied The elastic buckling modes and buckling load characteristics of high-rise diagrid tube structures with different ring beam arrangements are analyzed The buckling load of high-rise diagrid tube hybrid structure with double lateral force resistance system is derived theoretically.The factors affecting the overall stability of the structure are analyzed by using the ratio of stiffness to weight and the overall stability coefficient.Based on the static elastic-plastic analysis method and elastic-plastic time-history analysis method,the seismic response of high-rise diagrid structure is analyzed.The plastic development sequence,internal force distribution,stiffness degradation and energy distribution of high-rise diagrid structure are studied.It is analyzed that in the high-rise diagrid structure,when the angles of diagonal columns of different models are different but the equivalent lateral stiffness is the same,When the total mass of the structure is small,its seismic performance is better.The seismic performance of high-rise diagrid-tube hybrid structure is better than that of high-rise diagrid-tube structure.The vulnerability of high-rise diagrid structure is analyzed by incremental dynamic analysis method,and the probability evaluation of its failure states under different earthquakes is carried out.The structural vulnerability index is introduced to evaluate whether the high-rise diagrid structure can achieve the expected seismic fortification goal.At the same time,the collapse resistance of high-rise diagrid structure is evaluated.