南昌文体中心大跨度重型钢结构桁架设计关键问题分析

Analysis on key issues in design of large⁃span heavy steel structure truss of Nanchang Cultural and Sports Center

南昌文体中心项目采用大跨度重型钢结构桁架实现了最大99m的无柱空间。为了阐述大跨度重型钢结构桁架的设计思路,考察设计、施工中各因素的影响,通过理论分析和数值模拟细致地讨论了涉及的关键问题,包括杆件布置、支承条件、关键节点构造、施工过程的影响等。结果表明:腹杆布置形式对弦杆内力的影响较小;重型桁架两支承端的连接处理至关重要,应注意保证弦杆轴力在极限承载状态下的有效传递,并弱化弯矩的影响;整体提升施工方案对结构内力分布影响较大,“后激活”部分杆件的方法可以考虑提升过程中桁架端面的转动效果,更为准确地体现施工过程的影响。

Nanchang Cultural and Sports Center project adopts large⁃span heavy steel structure truss to achieve a maximum column⁃free space of 99m.In order to elaborate the design idea of large⁃span heavy steel structure truss,as well as investigate the influence of various factors in design and construction,the key issues were discussed in detail through theoretical analysis and numerical simulation,including layout of truss members,support conditions,structure of key joints,impact of the construction process,etc.The results show that the layout of the web member has little influence on the internal force of the chord member.Treatments of the two supporting ends of the heavy truss is very important.Attention should be paid to ensuring the effective transmission of the axial force of the chord member in ultimate bearing state and weakening the influence of the bending moment.Integral lifting construction scheme has a great influence on the internal force distribution of the structure.The method of"post⁃activation"can consider the rotation effect of the end face of the truss during the lifting process,and reflect the influence of the construction process more accurately.