大跨径三塔缆索承重桥力学性能研究

分别建立了三塔缆索承重桥3种桥型的有限元计算模型,通过对比研究,给出了3种桥型的一些力学特性.进行主跨为1 400m的3种桥型方案试设计,论证了3种桥型的可行性,给出了三塔缆索承重桥的一些经济特性.对比了3种桥型的施工方法,论述了施工期间力学性能较佳的桥型.研究结果表明:协作桥的中塔主缆抗滑移稳定性较难满足设计要求;3种桥型索塔的轴力相近,而斜拉桥主梁的轴力很大,稳定性相对较差;斜拉桥扭弯频率比最大,比悬索桥大37%左右,比协作桥大8%左右;协作桥经济性能较佳,其单位面积造价比斜拉桥和悬索桥分别少29%和15%;悬索桥的施工工艺较为成熟,施工期间具有更好的稳定性.

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

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.