Abstract: Based on the idea of unloading arch ribs and no anchorage for suspension bridges, a new bridge structure system — cable-arch composite bridge was proposed, which was mainly composed of a main arch, a main cable, two main towers, two side arches and a main girder. By choosing appropriate parameters such as vertical-span ratio, sagittal-span ratio and arch axis to adjust the proportion of arch and cable to share the load of the main span bridge deck, the cable could bear more loads. Furthermore, the arch rib could be unloaded substantially, which not only reduced its stress level, but also improved its stability; thus, the span of the cable-arch bridge could surpass the traditional arch bridge. Taking the 1008m span as an example, a conceptual design of cable-arch bridge was carried out, and the strength, stiffness and stability of the structure were studied by finite element method. The study shows that the cable-arch bridge not only retains the characteristics of high bearing capacity and rigidity of suspension bridge, but also has certain aesthetic value.

Key words: bridge engineering, cable-arch bridge, arch rib, main cable, anchor body, concept design

摘要： 采用给拱肋卸载及悬索桥不设锚碇的理念，提出一种新的桥梁结构体系——缆拱组合桥，其主要由主拱、主缆、主塔、边拱及主梁组成。通过选 取适宜的垂跨比、矢跨比、拱轴线等参数来调整拱和缆分担主跨桥面荷载的比例，让缆承担更多荷载，从而拱肋得到大幅度卸载，既降低了其应力水平 ，又提高了稳定性，使缆拱桥的跨径可以超越拱桥。以1 008 m跨径为例，对缆拱桥进行概念设计，并通过有限元研究其结构强度、刚度、稳定性等问题 。研究表明：缆拱桥不仅保留了悬索桥承载力高、拱桥刚度大的特点，同时还具有一定的美学价值。

关键词: 桥梁工程, 缆拱桥, 拱肋, 主缆, 锚体, 概念设计