中关村国家自主创新展示中心折线形布索预应力钢桁架结构设计研究

中关村国家自主创新展示中心采用折线形预应力大跨度空间桁架钢结构体系,该预应力体系在同类钢结构工程中应用很少,因此结构预应力体系选型及施工方法模拟分析对工程的安全性和可靠性具有重要的意义。采用不同计算模型,选取拉索布置形式、预应力度、桁架高跨比等几种主要参数,进行结构体系布局研究,总结预应力体系选型关键参数的合理取值范围;对相同承载力控制指标下预应力体系与非预应力体系进行了静力分析及静力弹塑性全过程分析,确认了预应力体系的有效性;应用单元生死法对结构预应力施工进行全过程模拟计算,分析了不同支撑安装方式对结构最终力学性能的影响,确定了合理的施工方案;同时进行了折线形转换节点的预应力损失分析及摩阻试验,通过对比位移、索力等关键参数的施工监测数据与理论计算值,验证了结构设计的安全性。

Design and research on a prestressed steel truss structure with broken line form cable in exhibition center of National Innovation of Zhongguancun

A large-span space truss structure with broken line form prestressed cable is used in exhibition center of National Innovation of Zhongguancun.The prestressed system is seldom used in similar steel structure engineering,therefore the selection of prestressed structure system and simulation analysis of construction method have vital significance on the safety and reliability of the project.Different calculation models were adopted and several main parameters,such as layout forms of cables,prestressed degree,height-span ratio of truss were selected to research the distribution of structure system and summarize the reasonable selection of the key parameters of prestressed system.Under the same control index of bearing capacity,the performance of the static and static elastic-plastic of prestressed system and non-prestressed system were analyzed to confirme the effectiveness of prestressed system.The method of killing or activating element was applied to simulate and calculate the whole process of prestressed construction of structure.The influence on the final mechanical properties of the different support installation ways was analyzed and the reasonable construction plan was determined.The analysis of prestress loss of broken line form transfer joint and the friction resistance test were also done.By comparing the key parameters,such as displacement,cable force and so on between construction monitoring data and theoretical calculations,the security of the structural design was verified.