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竖向预应力损失过大和分布不均是引起箱梁桥腹板开裂的重要原因。基于理论分析与试验研究,针对竖向预应力分段张拉、现行的施工工艺缺陷造成竖向正应力分布不均和预应力损失过大的问题,提出滞后张拉、二次张拉概念、拉伸-扭矩法张拉工艺,以及三者结合的悬臂箱梁桥竖向预应力施工流程,并在实桥应用中取得良好的效果。研究成果可为类似工程竖向预应力施工提供参考。
The vertical prestress loss is too large and uneven distribution is caused by the girder bridge web cracking an important reason. Based on the theoretical analysis and experimental research, in view of the vertical prestressed section tensioning and the problems of the current construction technology, such as uneven distribution of vertical normal stress and excessive loss of prestress, the concept of delayed tension and secondary tension is put forward. Stretch-torque method of tensioning process, as well as the combination of the three cantilever box girder vertical prestressed construction process, and the application of real bridge and achieved good results. The research results can provide a reference for the similar engineering vertical prestressed construction.