框架-核心筒结构外框刚度贡献的直接计算法与间接评估法

Direct calculation method and indirect evaluation method of the outer frame stiffness contribution of frame-core tube structure

针对框架-核心筒结构体系抗震设计,提出2种新的评估外框刚度贡献的方法:直接计算法和间接评估法。前者通过施加侧向荷载直接计算核心筒抗侧刚度和整体结构的抗侧刚度,通过差值比例得到外框刚度贡献率;后者则通过一个新的结构指标“二阶平动周期比”来间接反映外框刚度的贡献率,通过理想案例研究了影响“二阶平动周期比”数值的相关因素和基本规律。选择8个实际工程案例,分别采用2种方法对其外框刚度贡献进行了评价,并对2种方法评价结果的相关性进行研究。对比显示,2种方法得到的结果基本一致,能够相互印证。在此基础上,将框架-核心筒结构外框刚度贡献分为较低、中等和较大3个区间,并分别给出对应的指标数值范围。对2个实际工程采用不同种方法进行外框刚度评估,并对其抗震性能进行验证,结果表明,采用文中方法能够更加合理评价框架-核心筒外框刚度贡献,形成更加科学的抗震设计。

In the seismic design of frame-core tube structure,two new methods are proposed to evaluate the contribution of outer frame stiffness,one is direct calculation method,the other is indirect evaluation method.The former directly calculates the lateral stiffness of the core tube and the overall structure by applying the lateral load,and obtains the contribution rate of the outer frame stiffness through the ratio of difference.The latter indirectly reflects the contribution rate of the outer frame stiffness through a new structural index“second-order translational period ratio”.The relevant factors affecting the value of“second-order translational period ratio”are studied through an ideal case.Eight practical engineering cases are selected to evaluate the contribution of frame stiffness by two methods,and the correlation between the evaluation results of the two methods is studied.The results show that the results of the two methods are basically the same,which can confirm each other.On this basis,the outer frame stiffness contribution of frame-core tube structure is divided into three parts that are low,medium and large,and the corresponding index ranges are specified.Different methods are used to evaluate the stiffness of the outer frame of two practical projects,and the seismic performance is also investigated,the results show that methods in this paper can be used to evaluate the frame stiffness contribution of frame-core tube structure more reasonably and provide more scientific seismic design.