可抬起柱脚连柱支撑钢框架塑性极限承载力分析

Plastic Ultimate Bearing Capacity of Linked Column Steel Braced Frame with Lift Column Base

可抬起柱脚连柱支撑钢框架是一种新型可更换构件的结构体系,提出了一种可抬起柱脚的构造形式,分析了水平地震作用下该结构体系的变形特征。建立了连柱钢支撑框架极限状态下的典型屈服机制,基于虚功原理和小变形假定,推导出多高层连柱钢支撑框架的水平极限承载力计算公式。采用有限元软件ABAQUS建立了3层算例模型,其中可抬起柱脚采用非线性弹簧单元Spring2模拟,对其进行推覆分析,并与极限承载力计算的结果进行比较。研究表明:水平荷载作用下,连柱的柱脚向上抬起,耗能连梁两端相对运动明显,塑性损伤充分发展;有限元计算结果验证了极限承载力计算公式的合理性,此公式可为工程设计提供参考依据。

Linked column steel braced frame with lift column base is a new replaceable component structural system.A structural form of lift column base is proposed,and the deformation performance of this structural system under horizontal earthquake is analyzed in this paper.Based on its mechanical performance,typical yielding mechanism of linked column braced steel frame with lift column base is analyzed in the limit state.Based on the virtual work principle and the small deformation assumption,the formula of horizontal ultimate bearing capacity of multi-story and high-rise steel braced frame is derived.A 3-story numerical example model is established by using ABAQUS,in which the nonlinear spring element Spring2 is used to simulate the lifting column base,and the results are compared with the calculation results of ultimate bearing capacity.The results show that the columns with lift base can move upwards under the horizontal load,and the relative movement of two ends of the energy-dissipating link beam is obvious,with fully developed plastic damage.The finite element calculation results can verify the rationality of the calculation formula of ultimate bearing capacity,which can provide reference for engineering design.