预应力混凝土连续刚构箱梁桥底板裂缝成因分析研究

Analysis of bottom plate Cracks of Continuous Rigid-frame Prestressed Concrete Box-girder Bridges

针对预应力混凝土连续刚构箱梁桥底板裂缝成因分析不完善的现状,结合一座实际桥梁,通过有限元程序ANSYS的数值模拟,定量地分析了材料泊松效应对底板应力的影响程度,同时分析了底板预应力筋导致底板出现纵向裂缝的力学机理。分析结果表明:泊松效应尽管是导致底板开裂因素之一,但不是主要因素;而底板纵向裂缝的产生除了传统理论所认为的底板连续索所产生的径向力效应外,底板连续索导致的箱梁翘曲效应与局部小梁效应也是重要的、不可忽略的因素。

Aiming at imperfect of the causes for the cracks in continuous rigid-frame pre-stressed concrete box-girder bridge bottom plate,numerical simulation were completed with finite element program(ANSYS) based on an actual bridge.the stress effect of material Poisson impact on the bottom plate is analysed quantitatively,the mechanism of longitudinal cracks in soleplate resulted from prestressed tendonsis analysed too.The results show that although the effect of Poisson is one of the factors that led to the cracking of soleplate,but not a major factor.Among the causes of the longitudinal cracks in bottom plate,notonly the radical force are considered by traditional theory,but also the warping effect of the box and the local trabecular are serious and can not be ignored.