杭衢铁路(117+240+117)m三线部分斜拉桥主桥设计

Design of Changshan River Main Bridge on Hangzhou-Quzhou Railway

杭衢铁路常山江特大桥主桥为(117+240+117)m预应力混凝土部分斜拉桥,该桥为三线铁路桥,桥面宽21.3 m。采用塔梁固结、塔墩分离体系。主梁采用变高度单箱双室预应力混凝土箱梁;桥塔采用双柱式钢筋混凝土结构,高跨比1/4.62;斜拉索为强度1860 MPa的钢绞线拉索,每塔柱设8根索,双索面扇形布置,斜拉索锚固于主梁上,采用新型双侧抗滑鞍座式拉索锚固体系。通过空间有限元软件,对主桥的静动力性能、抗震性能及局部构造等进行计算分析,并采用车-桥耦合振动分析验证主桥的行车舒适性。结果表明,结构各项性能指标满足设计要求。同时得出以下结论:(1)索鞍局部构造细化改进后,可有效改善索鞍垫板下混凝土的受力;(2)三线铁路桥梁桥面宽、荷载大且工况多,三支座横向支反力分配检算分析表明,中支点处反力分布均匀,边支点处支座反力分布较不均匀;(3)基于局部分析确定的桥梁支座吨位和索梁锚固区的局部加强措施,可有效确保结构的受力安全。

The main bridge of Changshan River Bridge on Hanzhou-Quzhou Railway is a prestressed concrete partial cable-stayed bridge with span arrangement(117+240+117)m,which is a three-track railway bridge with deck width of 21.3 m.The bridge adopts the system of pylon-girder consolidation and pier-girder separation.Single box with two rooms prestressed concrete girder of variable height is adopted for the main girder.The bridge pylon with a height-to-span ratio of 1/4.62 is designed as double-column reinforced concrete pylon.8 stayed cables arranged in a fan-shape and consisted of 1860 MPa standard wires in each pylon are tensioned to connect the main girder and the pylon.A new type of saddle cable anchor system with double-sided anti-skid is adopted.The FEM software is used to calculate the static and dynamic performances of the bridge and analyze seismic resistance and local stress.Riding comfort is verified through vehicle-bridge spatial coupling vibration analysis.The results show that all the performance indexes of the structure meet the design requirements.The conclusions are as follows:(1)The stress of the concrete under the saddle plate can be effectively improved by the refinement of the local structure of the saddle.(2)The bridge deck of the three line railway bridge is wide,the load is large and there are many working conditions.The check and analysis of the lateral support reaction force distribution of the three supports shows that the distribution of support reaction of the middle support is uniform,and the distribution of support reaction of the side support is uneven.(3)Based on local analysis,the tonnage of bridge support and the local strengthening measures for the cable beam anchorage zone are proved to be effective in ensuring the safety of the structure.