预应力混凝土连续箱梁桥裂缝成因分析及其长期监测

The analysis on the cause of cracks in pre-stressed concrete continuous box girder bridge and the long-period monitoring

针对在桥梁建造和使用过程中出现的因裂缝而影响工程质量的问题,通过对一座在使用初期箱梁底板出现裂缝的在役预应力混凝土连续箱梁桥的长期监测、车辆荷载试验以及有限元法模拟分析,探讨了预应力混凝土连续箱梁的裂缝成因及其裂缝对使用性能的影响.结果表明,交通运输量的迅速增长导致了桥梁实际使用荷载超过当年设计荷载,使得箱梁的横向应力超过了混凝土的抗拉强度,是预应力混凝土连续箱梁桥出现纵向裂缝的一个主要原因。

The report is focused on the construction quality problems caused by cracks during construction and service of bridges, the thesis analyzes the cause of cracks in pre - stressed concrete continuous box girder bridge and effects of service performance for cracks in such ways as the long - period monitoring, vehicle - load experiments and the finite element method with the software ANSYS. The results show that the rapid growth of transportation leads to a result that the actual load of the bridge is much higher than the design load, wich makes the horizontal stress of the girder surpasses the tensile strength of concrete. It is a main reason why vertical cracks appear in the pre - stressed concrete box girder bridge.