预应力混凝土连续箱梁桥裂缝病害的加固方法分析

The Reinforcement Method Analysis of Cracks of the Prestressed Concrete Continuous Box Girder Bridge

以某高速公路上三跨预应力混凝土变截面连续箱梁桥作为背景工程,针对该桥墩顶和跨中出现的大量裂缝进行机理研究,根据裂缝产生机理选择体外布置预应力束的加固方法;应用空间杆系有限元精细化分析程序Wiseplus建立实桥的有限元模型,并且对体外布置预应力束进行模拟,有限元分析中荷载考虑了正应力标准组合,组合值包括恒载、车辆活载、混凝土的徐变、整体温度场、梯度温度场以及基础沉降产生的附加内力。通过有限元计算分析,对比了加固前和加固后的梁体的各项应力指标,分析表明,加固方法能够较显著的提高该桥墩顶和跨中的压应力储备,对于针对性的病害具有良好的处理效果。

Taking three span prestressed concrete continuous box girder bridge with variable cross section in a highway as the background, the mechanism of cracks in the bridge pier top and cross was explored, and the strengthening method of the external strand was adopted according to fracture mechanism. The real bridge model was established by the fine finite element program Wiseplus, and the external strand was simulated by the finite element analysis. The combination of normal stresses was considered in the finite element analysis, including the dead load, the live load of the vehicle, the creep of con- crete, the temperature field of the whole, the additional internal force generated by the gradient temperature field and the foundation settlement. The beam stress index analysis showed that the reinforcement method can significantly improve the compressive stress of the pier top and the cross. The analysis shows that the reinforcement method can significantly improve the compression stress of the bridge pier top and the cross, and has good treatment effect to the disease.