宽幅钢箱梁斜拉桥空间行为数值分析

Numerical Analysis on Spatial Behavior of Cable-stayed Bridge with Wide Steel Box Girder

为研究港珠澳工程青州航道斜拉桥的力学性能,分别采用空间梁单元模型和板壳精细化模型对施工阶段、成桥状态和运营阶段进行了仿真模拟分析,研究了施工、成桥和运营状态下青州航道桥的空间受力行为,分析了悬拼阶段及成桥状态下箱梁的横向变形,并对比分析了2种模型的计算结果。研究结果表明:考虑几何非线性的梁单元模型可分析宽幅钢箱梁斜拉桥的主要纵向受力行为,但不能准确反映桥塔及结构的横向受力状态;钢箱梁悬拼过程中横向变形以弯曲变形为主,翘曲等影响较小,桥面吊机前支点反力是引起梁段横向错缝过大的主要因素;成桥后主梁在自重与索力作用下的横向变形并不均匀,无索区箱梁边腹板处相对于桥面中心线下挠,而索区相对于桥面中心线处上挠,横截面的翘曲现象明显。

To investigate the mechanical performance of the Qingzhou Channel Cable-stayed Bridge in Hong Kong-Zhuhai-Macao engineering,construction stage,completion state and operating stage were simulated and analyzed by three-dimensional beam elements model and shell refined model.The mechanical behaviors of the bridge in these different stages were obtained and so did the transverse deformation in cantilever assembly stage and completion state.The comparisons were also made between calculated results by two finite element models（FEM）.The results show that the beam element model which considering geometric nonlinearity could be applied to analyze main longitudinal mechanical behaviors of cable-stayed bridges with wide steel box girder but couldn＇t accurately reflect the transverse behaviors of bridge tower and its structure.The transverse bend deformation takes the dominant position than the warpage in cantilever assembly stage.The reaction force at the front support of crane is the main reason of the larger transverse joint in girder segment.The transverse deformation of main girder is unevenunder the load of self-weight and cable tension in completion state.The down deflection occurs in web plate of none cable segment,while the up deflection occurs in girder segment comparing to the central line of bridge deck.There is significant warping at the transverse section.