某波形钢腹板箱梁桥悬浇过程中底板开裂成因分析

Analysis on the Causes of Bottom Plate Cracking during Suspended Casting for a Box Girder Bridge with Corrugated Steel Webs

混凝土开裂是桥梁结构的常见病害之一,而导致混凝土开裂的原因有很多。文章针对某波形钢腹板箱梁桥在悬浇施工过程中产生的底板开裂问题进行研究,利用有限元分析软件Midas/FEA建立了该桥的梁段模型,分析了混凝土水化热作用下的应力分布情况,并基于此对裂缝成因进行了分析。结果表明,混凝土水化热是导致箱梁底板开裂的主要原因,在水化热作用下,箱梁底板拉应力明显高于混凝土的抗拉强度。有限元模拟得到的裂缝发展方向与现场实测结果保持一致。文章研究成果可以为类似梁底开裂问题提供参考。

Concrete cracking is one of the common diseases of bridge structures,and there are numerous reasons leading to concrete cracking.In this paper,the cracking in the bottom plate for a box girder bridge with corrugated steel webs during suspended casting was investigated.The model for one segment of this bridge was established using Midas/FEA,the stress nephogram under concrete hydration heat was analyzed,and based on this,the cause of cracks was analyzed.The results show that the temperature gradient effect caused by concrete hydration heat of the box girder is the main cause of cracking in the bottom plate.Under the effect of hydration heat,the tensile stress of the box girder bottom plate is obviously higher than the tensile strength of concrete.The crack development direction obtained by finite element simulation is consistent with the field measured results.The research results of this paper can provide reference for similar concrete cracking problems in bridge structures.