含自复位伸臂桁架的超高层结构地震响应研究

Study on seismic response of supertall structures with self-centering outrigger truss

为了研究自复位防屈曲支撑(SCBRB)对超高层结构震时最大变形和震后残余变形的协同控制效果,本研究选取一栋75层、高度为344.85 m、伸臂桁架腹杆为防屈曲支撑(BRB)的超高层建筑作为原型结构,以此为基础设计了伸臂桁架的腹杆为SCBRB的案例结构。建立了2个超高层案例结构的弹塑性分析模型,并开展了非线性时程分析,对比了结构关键地震响应,验证了SCBRB对超高层结构震时最大变形和震后残余变形控制效果。结果表明:将框架-核心筒-伸臂桁架抗侧力体系的超高层结构的伸臂桁架中的BRB腹杆替换为设计参数合理的SCBRB腹杆,结构最大层间位移角可满足规范要求。采用2种腹杆的结构层间位移角分布模式一致,且SCBRB腹杆的最大层间位移角控制效果略优于BRB腹杆。相比于BRB腹杆,SCBRB腹杆在地震作用下残余变形更小,具有更好的自复位能力。SCBRB腹杆可有效提升框架-核心筒-伸臂桁架混合抗侧力体系的超高层结构的自复位能力,控制结构震后残余变形。基于SCBRB可实现超高层结构震时最大变形和震后残余变形的协同控制,本研究的相关成果可为超高层建筑的设计和相关研究提供参考。

To investigate the effect of self-centering buckling-restrained brace(SCBRB)on the dual-objective control of the maximum deformation during earthquake and the residual deformation after earthquake of supertall buildings,a 75-story supertall building with a height of 344.85 m and buckling restrained braces as web members of outrigger was selected as the prototype structure. Based on this,a study case with SCBRB as web members of outrigger was designed. Nonlinear finite element model of these two buildings were established and nonlinear time-history analyses were conducted. The critical seismic responses of two structures were compared,and the effect of SCBRB on the dual-objective control of the maximum deformations during earthquake and the residual deformation after earthquake was verified. The results indicated that for supertall structure with the frame-core tube-outrigger system,replacing the BRB web of the outrigger with SCBRB web with reasonable design parameters,the maximum inter-story drift ratio of the structure can meet the requirements of the code. The distribution trend of the inter-story drift ratio of the study cases with the two types of webs are consistent, and the control effect of the maximum inter-story drift ratio of the SCBRB web is slightly better than that of the BRB web. Compared with BRB web members,SCBRB web members exhibit lower residual deformation and better self-centering capacity under earthquake. SCBRB webs could effectively improve the self-centering capacity of supertall buildings with the frame-core tube-outrigger system, and control the residual deformation of the structure after earthquake. By introducing SCBRB,the dual-objective control of the maximum deformation during earthquake and the residual deformation after earthquake of the high-rise structure can be realized. The outcome of this study can provide references for the design and related research of supertall buildings.