常益长铁路沅江特大桥(34+118+240+118+34)m矮塔斜拉桥设计

Design of(34+118+240+118+34)m Extradosed Cable-stayed Bridge on Changde-Yiyang-Changsha Railway

常益长铁路沅江特大桥主桥采用(34+118+240+118+34)m矮塔斜拉桥跨越沅江航道,塔梁墩固结体系。主梁采用预应力混凝土直腹板变高箱梁,单箱双室截面;桥塔采用双柱式钢筋混凝土结构,高跨比1/5.16;斜拉索采用强度为1860 MPa的钢绞线拉索,每塔柱设10根索,扇形平行双索面;主墩采用圆端型双肢薄壁墩,采用低桩承台,群桩基础。通过空间有限元软件对主桥静力及动力性能、抗震性能、局部构造等进行结构安全性分析,并采用车-桥耦合振动分析验证主桥行车舒适性是否满足要求。结果表明,本桥具有良好的刚度及承载力,各项指标满足相关规范和铺设无砟轨道要求,为同类大跨无砟轨道桥梁的设计研究提供参考和借鉴。

The main bridge of Yuanjiang river bridge on Changde-Yiyang-Changsha railway is designed as an extradosed cable-stayed bridge with consolidation system and five spans of 34 m,118 m,240 m,118 m and 34 m.The prestressed concrete beam of variable height adopts a cross-section of two-cell and single box.The bridge tower with a height to span ratio of 1/5.16 is designed as double column reinforced concrete pylon.10 stayed cables arranged in a fan-shape and consisted of 1860 MPa stranded wires in each pylon are tensioned to connect the main girder and the pylon.The main pier designed as double-leg thin-walled pier rests on the pile group foundation of low pile cap.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 indicators of the bridge satisfy the requirements of standards and laying ballastless track with good stiffness and bearing capacity,providing references for the design and research of similar long span ballastless track bridges.