（同济大学建筑设计研究院(集团)有限公司， 上海 200092）

［摘要］某景观人行桥为跨度165 m的三跨连续悬索桥，主跨加劲梁竖曲线为圆弧，空间曲线主缆与索塔均朝横桥向外侧倾斜。根据桥梁的景观要求、几何形态与尺度、轻载特征及场地条件，设计了摇摆索塔的自锚式悬索桥结构系统。摇摆索塔由倾斜的桅杆与背索组成，缆索、桅杆及加劲梁共同形成了稳定的空间整体张拉结构系统。采用了桅杆-背索-加劲梁的整体式支座桥墩，在横桥向形成自平衡系统，抵消了桅杆的地基压载并避免了设置背索的重力锚碇。加劲梁重量轻，缆索的重力刚度很小，需要施加额外的预应力。为此通过初始预应力态设计来确定结构的预应力度，以外倾的平面悬链线为初始几何构形，根据索杆节点静力平衡条件计算主缆的初始预应力态空间线形与内力，按不动点原则和桅杆顶点的静力平衡条件确定桅杆-背索的受力平面方位。分别采用加劲梁的鱼骨式与壳单元有限元模型，计算了整体结构的静力与动力性能。计算结果表明：预应力增加了索杆系统的刚度与稳定性，减小了加劲梁的挠度； 整体结构具有合理的刚度、稳定性与承载能力； 相关结构性能指标符合设计规范的要求。

［关键词］自锚式悬索桥； 摇摆式索塔； 整体张拉结构； 初始预应力态； 主缆空间线形； 刚度； 稳定性

中图分类号：TU394文献标识码：A文章编号：1002-848X(2020)22-0119-06

Structural design and analysis of a spatial integral tension suspension bridge

YANG Huizhu, WU Shuigen, DAI Chongmin

(Tongji Architectural Design (Group) Co., Ltd., Shanghai 200092, China)

Abstract:A landscape pedestrian bridge is a three-span continuous suspension bridge with a span of 165m. The vertical curve of the main span stiffening beam is a circular arc, and the spatial curve of  main cable and the cable tower are inclined to the outside of the horizontal bridge. According to the bridge′s landscape requirements, geometry and scale, light load characteristics and site conditions, a self-anchored suspension bridge structure system with swinging towers was designed. The swinging tower was composed of inclined masts and back cables. The cables, masts and stiffening beams together formed a stable spatial integral tension structural system. The monolithic supporting pier with mast, back cable and stiffening beam was adopted to form a self-balancing system in the transverse direction, which offset the foundation ballast of the mast and avoided the setting of the gravity anchorage of the back cable. The stiffening beam was light in weight, the gravity stiffness of the cable was very small, and additional prestress was required. For this reason, the initial prestress state design was used to determine the prestress degree of the structure. The cambered plane catenary was the initial geometric configuration. According to the static balance condition of the cable-rod node, the initial pre-stressed space line shape and internal force of the main cable were calculated, and the force plane orientation of the mast and back cable was determined according to the fixed point principle and the static balance condition of the mast vertex. The fish-bone and shell element finite element models of the stiffening beam were used to calculate the static and dynamic performance of the overall structure. The calculation results show that the prestress increases the stiffness and stability of the cable-rod system, and reduces the deflection of the stiffening beam; the overall structure has reasonable stiffness, stability and bearing capacity; the relevant structural performance indicators meet the requirements of the design code.

Keywords:self-anchored suspension bridge; swing cable tower; integral tension structure; initial prestressed state; spatial curve of main cable; stiffness; stability

*新形态大跨度柔性景观人行桥设计的关键技术(2020J-JG02)。

作者简介：杨晖柱，博士，高级工程师，一级注册结构工程师，Email: YangHuiZhu@163.com； 通信作者：吴水根，硕士，教授级高级工程师，一级注册结构工程师，Email: shuigen111@tongji.edu.cn。