大跨径三塔缆索承重桥力学性能研究

Research On Mechanical Properties Of Large Span Three-Town Cable Supported Bridges

摘要:

针对三塔缆索承重桥的三种结构体系，自设计主跨为1400m的方案，并建立三种体系的有限元分析模型，通过对比研究，获得三塔缆索承重桥的一些力学特性。研究结果表明，经索力优化后，三种体系在成桥状态下主梁的弯矩分布均匀，且量值相近。总体上，斜拉体系的塔、梁荷载响应较大，且因主梁承受较大的轴压力，结构整体稳定性差，但其扭弯频率比大，对抗风抗震有利。悬索体系除中塔活载弯矩较大外，塔、梁荷载响应均最小，且结构整体稳定性佳，但其扭弯频率比低，对抗风抗震不利。协作体系的力学性能处于两者之间，且突出两者优点。

Abstract:

This study focused on mechanical property of large span three-town cable supported bridges, including suspension bridge, cable-stayed bridge and cable-suspension Bridge. The method was through the design of these type bridges to compare their mechanical characteristic. The main span of these bridges was 1400 meter. The result of this investigation clarify that moment diagram of box girder of the three bridges is similar to each other after cable force optimum. As a whole, internal force of beam and town of cable-stayed bridge is largest. Additionally the stability of cable-stayed bridge is not well because the axis force of its box girder is larger. However, the ratio of the natural frequencies of the flexural and torsional vibrations is larger than others. So the aseismic and wind-resistant behaviors of cable-stayed bridge is best. Internal force of beam and town of suspension bridge is smallest and its stability is highest, except the moment of bottom of the middle town due to live load, while the ratio of the natural frequencies of the flexural and torsional vibrations is lowest. So, the aseismic and wind-resistant behaviors of suspension bridge is worst. Internal force of beam and town of cable-suspension Bridge is between the two formers and the advantages are highlighted.