预应力混凝土连续梁桥合龙区域裂缝成因分析

该文就广州市某大桥合龙区域箱梁底板预应力张拉时,较多裂缝出现在箱梁底部的情况,通过现场勘察和计算分析,发现钢束实际产生的向下拉力远大于理论值。实际荷载作用下的箱梁局部分析表明过大的拉力拉断钢束孔道侧壁,导致裂缝的产生。文中针对该类裂缝提出了预防建议。

Analysis of Cause Forming Crack in Closing-up Area of Prestressed Concrete Continuous Girder Bridge

The article introduces that more cracks occur at the bottom of box girder when the box girder bedplate in a bridge closing-up area of Guangzhou City is pre-stressing stretched. Through the field survey and calculating analysis, it is found that the downward stretching force actually produced from steel strand is far greater than theoretical value. The partial analysis of box girder under the actual load action makes clearly that the over-great stretching force breaks the side wall of steel strand hole so as to lead the production of cracks. In view of this kind of crack, the article puts forward the preventive suggestions.