谈后张预应力筋对大跨度连续刚构桥的影响性能

Effect of Prestressed Reinforcement on the Long Span Continuous Rigid Frame Bridge

随着大跨度连续刚构桥的长期使用,桥梁不可避免会出现中跨开裂及挠度不断增加等问题。为了提高梁的使用寿命,增加后张预应力筋可以有效地增加主梁的预应力,并减小大跨度梁的挠度。同时,适当的张拉位置对于优化桥梁的应力分布及控制挠度的增加是非常重要的。论文结合工程实例,具体分析后张预应力筋不同位置(包括顶板、腹板和底板)对于主梁的应力及挠度的影响,并找出后张预应力筋的最佳位置。

The problems like cracking of the girder in the mid-span and the ever-increasing vertical deflection appear during the long term usage of the long-span continuous rigid-frame bridge. Post-tension tendon with reserved duct can increase the pre-stress of the main beam effectively, and decrease the long term span deflection in order to improve the performance ofthe girder. At the same time, the proper tension position is very crucial to optimise the stress distribution of the bridge and control the deflection increase. Combining with practical engineering, the authors analyze the influence of different positions of post-tension tendon （ including top-, web and bottom plate tendons） on the stress and deflection of the main beam, and find out the optimal position of post tendon.