Robustness Analysis For Progressive Collapse Of High-rise Diagrid Structures Based On Alternative Path Method

In recent years,diagrid structure have been widely used in high-rise buildings due to its strong lateral stiffness.People have studied the performance of high-rise digrid structures under various loads,but there are few studies on the ability of high-rise diagrid structures to resist progressive collapse under accidental loads and strong earthquakes.Therefore,based on alternative path method and Pushover analysis method,the progressive collapse resistance of high-rise diagrid structures was discussed.The detailed research contents and conclusions are as follows:(1)The basic regularity of the element importance index of the diagrid structures was obtained.The average value of the element importance index in each module was analyzed.It is found that the average value of the module is lowered from the bottom up.The element importance index distribution of the structure under different lateral loads is basically the same,but as the lateral force distribution is more uniform,the element importance index of the bottom module generally increases,and the importance coefficient of the upper module decreases.(2)The scope of influence of the removal of a single member on the structure.Removing any diagonal in the branch mainly affects the interlayer displacement angle of the floor where the branch is located.And the removal of the diagonal on the same branch has almost the same effect on the structural performance of the structure.(3)The progressive collapse resistance of high-rise diagrid structures was evaluated.Regardless of the dynamic effect or not,the redundancy index under all demolition conditions meets the requirements for non-collapse.After considering the dynamic effect,the ultimate bearing capacity of the structure is obviously reduced,and the redundancy index is generally smaller.(4)The ability of the frame structures and the high-rise diagrid structures to resist continuous collapse was compared.The redundancy index of the frame tube structure is smaller than that of the high-rise diagrid structures.And the high-rise diagrid structures have higher redundancy and better resistance to continuous collapse.