加强层弯曲刚度对框架-核心筒结构振动特性影响

Influence of outrigger bending stiffness on vibration characteristic of frame-core tube structure

假定外框柱的轴向刚度与核心筒的弯曲刚度沿结构高度不变,忽略转动惯量的影响,同时认为水平伸臂与外框柱铰接,与核心筒刚接。基于分布参数体系的振动理论,考虑核心筒剪切变形和加强层弯曲刚度的影响,对带有一道加强层的框架-核心筒结构体系进行动力分析,得出了该结构体系前三阶自振频率与加强层位置的关系,并对考虑加强层弯曲刚度影响时核心筒剪切变形所引起振动频率的变化进行了分析。分析结果表明:设计时应选择设置“有限刚度”的加强层,适当增加与水平伸臂相连的外框柱轴向刚度,合理设置加强层的位置,核心筒剪切变形对带加强层高层建筑结构的自振频率影响可忽略不计。

It is assumed that the axial stiffness of the outer frame column and the bending stiffness of the core tube are constant along the structural height,ignoring the influence of the moment of inertia.At the same time,it is considered that the horizontal outrigger is hinged with the outer frame column and rigidly connected with the core tube.Based on the vibration theory of the distributed parameter system,considering the influence of shear deformation of the core tube and bending stiffness of outrigger,the dynamic analysis of the frame-core tube structure system with an outrigger was carried out.The relationship between the first three natural frequencies of the structural system and the position of the strengthened layer was obtained.And the change of the vibration frequency caused by the shear deformation of the core tube when considering the bending stiffness of outrigger was analyzed.The results of analysis show that the design should choose to set the‘finite stiffness’of outrigger,appropriately increase the axial stiffness of the outer frame column connected to the outrigger,and reasonably set outrigger position.The influence of the shear deformation of the core tube on the natural frequency of the high-rise building structure with the strengthening layer is negligible.