在施混凝土斜拉桥主梁裂缝成因分析

Research on the Cause of Concrete Girder Crack Occurred in the Construction Stage of Cable-Stayed Bridge

为探明某π型截面混凝土斜拉桥施工过程出现裂缝的成因,建立了混凝土主梁标准节段实体有限元模型,用三次幂函数拟合混凝土强度龄期曲线,分析了混凝土收缩对主梁应力的影响。结果表明,在新浇筑混凝土养护的第一天,因不同龄期混凝土收缩而产生的最大拉应力超过了其早期抗拉强度,是产生裂缝的主要原因,最后提出了预防和控制该类裂缝的方法。

Cracks were found during the construction of a concrete cable-stayed bridge of girder section. In order to find out the cause of these cracks, a concrete entity model of the main girder was established in this paper and a three times power function was used to fit the concrete curve of strength and age to get the Influence of concrete shrinkage on the stress of main beam. It showed that the maximum tensile stress exceeds the early tensile strength of the concrete due to the shrinkage of new and old concrete at different shrink age in the first day of the new concrete curing. Finally, the method of prevention and control of the cracks were put forward.