南昌洪州大桥主缆锚固横梁设计研究

Study on Design of Cable Anchoring Beam of Hongzhou Bridge in Nanchang

摘要:

南昌洪州大桥采用50 m+120 m+252 m +120 m +50 m自锚式悬索桥，标准桥宽41.5 m。加劲梁在中跨（252 m）和次边跨（100 m）采用钢-混凝土组合梁；边跨（50 m）和次边跨（20 m）采用预应力混凝土梁进行配重和主缆锚固。单根主缆由37根索股组成，每根索股采用127根?5.5 mm镀锌高强平行钢丝。洪州大桥主缆采用分散式锚固结构方案，主缆各索股在理论散索点处逐步散开，分散锚固在横梁上，锚固横梁截面尺寸为6.0 m × 3.5 m。结合主缆锚固区的设计，采用实体有限元对锚固横梁前后锚面应力集中、锚固横梁双向受剪、人孔应力集中、横梁预应力D区效应等局部不利受力状态进行分析计算，以验证结构尺寸的合理性和受力的安全性，并对设计提出相应指导意见，为今后同类型桥梁结构的设计提供参考。

Abstract:

Hongzhou Bridge in Nanchang is (50+120+252+120+50) m self-anchored suspension bridge. The standard bridge is 41.5 m wide. The stiffened beam is the steel - concrete composite beam at the middle span (252 m) and the secondary side span (100 m). The side span (50 m) and the secondary side span (20 m) are carried out by prestressed concrete beams for counterweight and the main cable is anchored. The single cable consists of 37 cable strands, and each strand is made of 127 ?5.5 mm galvanized parallel high strength steel wires. The decentralized anchoring structure is used for the main cable of Hongzhou Bridge. Each strand of the main cable is gradually dispersed at the theoretical scatter point, and dispersed and anchored on the beam. The cross-sectional size of the anchoring beam is 6.0 m × 3.5 m. Combined with the design of the anchoring area of the main cable, the solid finite element is used to analyze and calculate the local unfavorable stress states such as stress concentration on the front and rear anchorage surfaces of the anchoring beam, two shear directions of the anchoring beam, manhole stress concentration and D zone effect of beam prestressing, which verifies the rationality of the structure size and the safety of stress. The corresponding guidance is put forward for the design, which provides the reference for the design of the similar bridge structures in the future.