北京某大跨转换桁架结构分析与设计

Analysis and design of a large-span transfer truss structure in Beijing

北京某学校项目因功能需求,形成了层高12m,跨度21m的转换桁架。通过对转换桁架腹杆不同布置方式以及主次桁架与平面桁架的对比分析,选择了斜腹杆全部受拉的平面桁架布置方式。因其竖向荷载大、桁架高度受限等难点,需对转换结构进行抗震性能化分析。通过设定转换柱、转换桁架等关键性构件以及首层框架柱、转换部位的二层框架柱重要构件在小震、设防地震,以及罕遇地震下的性能目标,进行了转换结构整体和构件承载力和抗震性能水准的评估。在全面分析的基础上,总结了转换桁架的结构设计要点和设计措施,为以后设计提供参考。

Due to the functional requirements of a school project in Beijing,a conversion truss with a floor height of 12m and a span of 21m was formed.Through the comparative analysis of the different arrangements of the web members of the transfer truss and the comparison between the primary and secondary trusses and the plane truss,the plane truss arrangement in which all the inclined web members are in tension is selected.Due to the difficulties of large vertical load and limited truss height,seismic performance analysis of the transfer structure is required.By setting the performance targets of key components such as transfer columns and transfer trusses,as well as frame columns on the first floor and important components of frame columns on the second floor at the transfer position under small earthquakes,fortified earthquakes,and rare earthquakes,the overall structure and components of the transfer structure are analyzed.Evaluation of bearing capacity and seismic performance levels.On the basis of comprehensive analysis,the key points and design measures of the structural design of the transfer truss are summarized to provide reference for future design.