雄商高铁黄河特大桥主桥桥型方案比选

Main Bridge Type Selection for a Huanghe River Bridge of Xiong′an-Shangqiu High-Speed Railway

雄商高铁黄河特大桥设计时速350 km,铺设无砟轨道。根据防洪及通航要求,该桥主桥中部跨度布置为(4×260+280)m,属于超长联大跨桥梁。结合桥址处建设条件、长联无砟轨道高速铁路桥梁建设及高速铁路行车要求,从桥型的边中跨比、梁高、结构体系、轨面平顺性能等方面,分别确定拱加劲连续钢桁梁桥、斜拉桥、部分斜拉桥、连续梁拱桥4种桥型的最佳方案,并对各桥型最佳方案进行技术经济综合比选。比选结果表明:斜拉桥方案在多跨情况下刚度小,采用多种工程措施提升刚度后造价最高;部分斜拉桥方案边塔尺寸较大,混凝土梁应力较高且工期较长,造价较低;连续梁拱桥方案采用钢-混混合梁减轻自重,合理跨度得到提升,造价高;拱加劲连续钢桁梁桥方案技术经济性好、受力性能较好、施工速度快,且与环境契合,因此最终采用该桥型方案。

The Huanghe River Bridge carrying a section of the Xiong′an-Shangqiu High-speed Railway consists of ballastless tracks and allows a train traveling speed of 350 km/h.To meet the flood protection and navigation requirements,the central part of the main bridge is arranged in four spans of 260 m and a span of 280 m,which is categorized as a long-span and long-continuous-unit bridge.Four types of bridges were compared,including the arch-stiffened continuous truss girder bridge.cable-stayed bridge,extradosed bridge and continuous girder arch bridge,from perspectives of side-to-intermediate span ratio,girder depth,structural system and track irregularity,aiming to accommodate the construction condition at the bridge site,since the construction requirements of high-speed railway bridge with long continuous units and ballastless tracks as well as train travelling comfort.And the ideal structural configurations of the four types of bridges were further compared technically and economically.As per the comparison,the cable-stayed bridge is inferior to other options in terms of stiffness,which is not a cost-effective option after taking measures to improve the stiffness.The extradosed bridge wins other options over its low construction cost,but the great side pylon dimension,high stresses in the concrete girder and long construction schedule weakens its competitiveness.When using the steel-concrete hybrid girder,the self-weight of the continuous girder bridge is reduced and the span arrangement will be more effective,but the construction cost is high.The arch-stiffened continuous steel truss girder bridge is of good economy and technical advantages,which is very competitive in terms of load bearing capacity,construction schedule,and co-existence with surroundings,which is finally selected.