南京奥体新城社区中心单榀长悬挑桁架门头结构设计

Structural Design of a Building Head with a Single Long Cantilever Truss of Nanjing Olympic Sports Community Center

文章介绍了南京奥体新城社区中心单榀长悬挑桁架门头结构选型时考虑的主要因素,并根据斜腹杆的材质、方向、布置楼层的不同,设计4种方案进行了计算对比。结果表明,各层均设置斜腹杆的钢-混凝土悬挑桁架方案在结构自重、控制变形、施工便利性方面有优势。然后,采用两种有限元软件分别模拟该桁架受力情况,两软件内力计算结果基本一致;通过提高抗震等级、增设平面外斜杆、梁内增设型钢等措施,提高桁架抗震能力、整体性、冗余度;楼板应力分析发现,悬挑桁架内一跨楼板在标准组合工况下受拉,楼板相应加强配筋;通过建立简化受力分析模型,对斜腹杆端部节点处进行内力分析,创新地设计了L形埋件,并对埋件、焊缝按不同受力形式包络设计;通过增大板厚、设置面外支撑梁、水平桁架,提高悬挑桁架抗侧力能力,弦杆水平向按悬挑梁设计。

This paper introduces the main factors considered in a single long cantilever truss structure form selection of a building head of Nanjing Olympic Sports Community Center.Four comparison schemes were designed according to the different materials,directions,and floors of diagonal web members.The results show that the scheme of steel-concrete cantilever truss with diagonal web members on each floor has advantages in structure self-weight,deformation control,and construction convenience.Then,two finite element softwares were used to simulate the stress conditions of the truss,and the internal force results of the truss by the two softwares were basically consistent.By increasing the seismic grade,adding out-of-plane diagonal members,and adding steel sections in the beam,the seismic capacity,integrity,and redundancy of the truss were improved.The stress analysis of the floor slab indicates that the floor slab at the back span of the cantilever truss was in tension when under D+L condition,and the rebars of the floor slab should be increased.By establishing a simplified stress analysis model,the internal force of the end nodes of the diagonal web members was analyzed,and the L-shaped embedded parts were designed innovatively.The embedded parts and welds were envelope designed according to different stress forms.By increasing the slab thickness,and adding outof-plane support beams,and horizontal trusses,the lateral force resistance of the cantilever truss was improved,and the chord members were designed as cantilever beams.