三塔斜拉桥设计参数分析

摘要

To study the mechanical behavior of the three‐pylon cable‐stayed bridge structure , combined with the real design cases of three‐pylon composite girder cable‐stayed bridge projects , the finite element model of three‐pylon composite girder cable‐stayed bridge was established to car‐ry out parametric study on the effect of the measures taken ,such as to superimpose stay cables , install stay cables between pylons ,improve pylon stiffness and add auxiliary piers ,and the varia‐tion law of their load bearing behaviors is concluded .The results of the calculation demonstrate that the load bearing capacity of the intermediate pylon ,main girder and stay cables can be effec‐tively improved by adding superimposed cables ,stiffening cables between pylons and auxiliary piers to side spans ,and the pier‐top horizontal displacement and the mid‐span deflection of the main girder can also be reduced .T he pier‐top displacement can be reduced by enhancing the stiff‐ness of the intermediate pylon .The increase of the stiffness of side pylons has little influence on the structure .The increase of the height of the intermediate pylon is capable of improving the in‐ternal force of the pylons ,but accelerating the pier‐top displacement .T he results of the calculation can provide reference for the design of configuratiion of three‐pylon composite girder cable‐stayed bridge structure .%为研究三塔斜拉桥结构的力学行为特征，为三塔斜拉桥设计提供参考，结合三塔结合梁斜拉桥工程设计实例，建立三塔结合梁斜拉桥的有限元模型，对斜拉索重叠布置、塔间斜拉索、提高桥塔刚度及采用辅助墩等措施进行参数分析，总结其受力行为的变化规律。计算结果显示：设置重叠索、设置塔间加劲索、边跨设置辅助墩可有效改善中塔、主梁、斜拉索受力，减少塔顶水平位移值及跨中主梁挠度值；提高中塔刚度可以减少塔顶位移；提高边塔刚度对结构影响很小；提高中塔的塔高可以改善桥塔内力，但会增大塔顶位移。计算结果可为三塔结合梁斜拉桥结构布置设计提供参考。