三塔悬索桥不同结构体系对结构静动力行为的影响

Impact of Different Structural Systems of Three-Tower Suspension Bridge on Its Structural Static and Dynamic Behavior

大跨径三塔悬索桥是一种新的结构形式,不同的约束形式对结构的内力与变形有一定的影响。采用有限元软件建立某三塔悬索桥有限元空间模型,对结构在不同的纵向约束和竖向约束体系下的静动力影响进行研究和对比。结果表明:纵向约束适宜仅设置在中塔处,在主缆与加劲梁间设置刚性中央扣需谨慎设计,也没有必要在三塔处均设置纵向约束;竖向约束在加劲梁能满足应力要求时,适宜采用连续加劲梁在中塔处固结的结构形式;在加劲梁设计受限时,不宜在中塔处设置竖向约束。

The long span three-tower suspension bridge is a new structure type and the different restraints arranged on the bridge will have a certain impact on the internal force and deformation of the structure.In this paper,the finite element software is used to set up the spatial finite element model for a three-tower suspension bridge and the static and dynamic impact of the structure under different longitudinal and vertical restraints is investigated and compared.The results of the investigation and comparison demonstrate that the longitudinal restraint is suitable to be arranged at the intermediate tower only,the rigid central cable band to be arranged between the main cable and stiffening girder should be cautiously designed and the arrangement of the longitudinal restraints at all three towers is not necessitated.In case that the stiffening girder can satisfy the need of stress,the vertical restraint is suitable to take the structural form of rigid fixity for the continuous stiffening girder at the intermediate tower and at the time the design of the stiffening girder is restricted,the vertical restraint is not suitable to be arranged at the tower.