城际铁路大跨跨线桥桥式方案研究

Research on Design Schemes for Long-span Intercity Railway Bridge over Railway Lines

广佛江珠城际铁路立交主桥一次跨越5条铁路线,桥址建设环境复杂。为选择合理的大跨跨线桥桥式方案,结合既有铁路现状、桥跨布设等控制条件,选择方案1(32+170+50+40+32) m钢-混混合梁独塔斜拉桥)和方案2(160 m简支钢桁梁)2种桥型方案,在结构形式、技术创新、经济性能、施工方案和对既有铁路影响等方面进行对比分析。结论:独塔混合梁斜拉桥和简支钢桁梁两个方案均技术可行,且在铁路桥梁领域有一定的创新性。方案1桥式布置合理、结构受力明确,施工便利安全,对运营铁路影响小,创新性的采用混合梁能充分发挥钢混两种材料性能,减小转体跨度和重力。基于安全性、施工难度和后期管理养护等因素,选择方案1为推荐方案,采用一次平转法施工,转体吨位达3.5万t。

The interchange bridge with complex construction environment on the Guangzhou-Foshan-Jiangmen-Zhuhai intercity railway is required to span five railway lines at one time.In consideration of the current situations of the railways,the control conditions of span arrangement and the construction scheme,two types of bridge schemes suitable for the interchange bridge,i.e.Scheme 1(32+170+50+40+32)m hybrid girder cable-stayed bridge with single tower),Scheme 2(160 m simply-supported steel truss girder)are compared and analyzed in terms of structural form,technical innovation,cost,construction plan and influence of existing railways.It is concluded that the two schemes of the single-tower hybrid beam cable-stayed bridge and the simply supported steel truss beam are technically feasible,and both have certain innovativeness in the field of railway bridge.Scheme 1 with the advantages of reasonable layout,clear mechanical behavior,convenient construction and little impact on the operating railway,innovatively adopts the hybrid beam to give full play to the properties of the two materials of steel and concrete,therefore,the span and weight of the rotating body are reduced.In view of security,construction difficulty,maintenance convenience and other factors,scheme 1 is recommended,which uses flat turn construction method with a tonnage of 35000 t.