大跨度钢管桁架结构施工顺序优选分析

以兰州大学体育馆实际工程为背景,采用有限元软件Midas Gen对大跨度钢管桁架结构施工过程进行分析.通过对吊装过程中钢管桁架各杆的轴力和应力进行验算,验证吊装过程的安全性.首先提出从左至右、从中间至两边和从两边至中间的3种吊装施工顺序,然后针对这3种安装顺序,分别对6～17轴施工阶段结构挠度和结构应力进行分析,最后对3种安装顺序对主桁架造成的位移和应力影响进行对比.结果表明,采用从两边至中间的施工方法可以有效抵消由桁架自重引起的几何积累效应,同时配合主桁架预起拱技术,使得整个桁架结构安装达到最佳状态.

Analysis of optimum selection of construction sequence of large-span steel tube trusses structure

Taking the actual engineering project of gymnasium in Lanzhou University as background project,the construction procedure of its large-span steel tube trusses structure was analysed by using finite element software Midas Gen.The axial force and stress in all trussed poles in hoisting process were checked,so that the safety of hoisting process was justified.Three kinds of hoisting sequence were proposed first,namely from left to right,from middle to both ends and from both ends to middle.Then the structural deflection and structural stress during these three hoisting stages were analyzed on axes from #6 to #17.Finally,the influence of these three hoisting modes on displacement of and stress in the main truss with each other were compared.The result showed that the geometric accumulation effect induced by the weight of the tube trusses could be neutralized effectively by using the third option of hoisting sequence,i.e.from both ends to middle.Meantime,the entire tube truss structure installation could reach an optimal state with pre-arch cambering of the main truss.