武汉古田桥——自锚式悬索桥设计及关键技术

Design and Key Techniques of Gutian Self-Anchored Suspension Bridge in Wuhan

武汉古田桥为(48+57+110+252+110+57+48)m自锚式悬索桥。加劲梁全长682m,采用混合梁结构形式,中跨252m及边跨93.5m范围为钢-混组合梁,其余2×(48+57+16.5)m范围为预应力混凝土箱梁。桥塔采用格构式钢-混组合结构门式塔,南、北岸塔高分别为69.624m和64.624m。主缆采用预制平行钢丝索股法形成。墩身采用双柱门式墩或独柱墩,基础采用钻孔灌注桩基础及混凝土矩形承台。钢-混组合加劲梁架设阶段,将钢梁大跨度顶推跨越通航水域,混凝土桥面板后期结合以使其具有较好的耐久性;格构式钢-混组合桥塔在降低现场吊装难度的同时,还解决了主鞍座处集中力过大的难题;采用"先缆后梁法"结构体系转换技术,利用主缆承载力架设组合梁的混凝土桥面板。

Wuhan Gutian Bridge is a self-anchored suspension bridge that has spans of (48+ 57+ 110+252+110+57+48) m. The length of stiffening girder with a structure of composite girder is 682 m, and the lengths of mid-span and side-span with a structure of steel-concrete composite girder are 252 m and 93.5 m respectively, while the other parts with spans of 2×(48+57+16.5) m consist of pre-stressed concrete box girders. The tower is the lattice-type portal-frame tower with a steel-concrete composite structure, and the heights of the south tower and north tower are 69.624 m and 64.624 m respectively. Main cables consist of prefabricated parallel wire strands. Piers are of double-column portal-frame structures or single-column structures. Concrete rectangle pile caps and bored piles are chosen to prepare the foundation. In the stage of erecting the steel-concrete composite stiffening girders, long-span steel girders are incrementally launched to span navigable waters, and concrete bridge decks are combined at late-stage to make it have better durability. The application of lattice-type steel-concrete composite tower can decrease difficulty in hoisting operations, and can solve the problem that the concentrated force on the main saddle is excessively large. The innovative system conversion technology of "erecting cables before constructing girder" is adopted, thus the concrete bridge deck of composite girder can be erected with the help of main cable bearing capacity.