曲线钢箱梁桥步履式顶推施工横向倾覆稳定性影响因素的分析

Analysis of factors influencing transverse overturning stability of curved steel box girder bridge by hydraulic-walking incremental launching construction

曲线钢箱梁桥在步履式顶推过程中的横向倾覆稳定性控制至关重要。采用有限元方法及计算对可能影响到倾覆稳定性的因素,包括轴线偏移、支点脱空、支点纵横向间距、风荷载进行系统的分析。结果表明:中轴线偏移、支点的纵横向间距对结构的横向倾覆稳定性影响较大;在顶推过程中应严格控制中轴线偏移量,尽量增大支点的横向间距,合理控制支点的纵向间距;支点的脱空可能导致结构发生横向倾覆失稳,特别是外弧侧和边支点截面的脱空影响更大;在顶推过程中应严格控制各支点顶推力,使支点均衡受力,共同工作;当风荷载较小时,其对结构的倾覆稳定性影响较小。

It is crucial to control the transverse overturning stability of curved steel box girder bridge in the process of hydraulic-walking incremental launching.The factors which may affect the overturning stability,including axis deviation,separation of fulcrum,vertical and horizontal spacing of fulcrum,and wind load,was analyzed systematically by using the finite element method.The results showed that the displacement of the central axis and the vertical and horizontal spacing of the fulcrum had great influence on the transverse overturning stability of the structure.In the process of pushing,the deviation of the central axis should be strictly controlled.The horizontal distance of the fulcrum should be increased as much as possible and the longitudinal distance of the fulcrum should be reasonably controlled.The detachment of the fulcrum may lead to the transverse collapse of the structure,especially the outer arc side and side fulcrum section.In the process of pushing,the pushing force of each fulcrum should be strictly controlled so as to make it work together with balanced force.When the wind load was small,it had little effect on the overturning stability of the structure.