异形拱座大体积混凝土水化热分析及施工应用

Analysis of hydration heat of massive concrete for shaped arch seats and application in construction

随着大体积混凝土的广泛应用,对温度应力与温度裂缝的分析和控制研究也越来越重要。现以某钢箱拱桥为例,运用有限元软件建立模型,分析了大体积混凝土承台和拱座的温度和应力变化,并介绍其相应的施工工序和技术,提出相应的防裂措施。结果表明:当入模温度为26℃时,承台和拱座各仓混凝土的理论温度峰值在43.5~55.5℃,均<65℃,满足规范要求;承台和拱座各仓在26℃入模温度条件下,混凝土在升温期间的理论主拉应力在1.09~2.28MPa之间,降温阶段后的理论主拉应力在0.47~1.13MPa之间。在施工过程中,应尽量降低入模温度来降低温度峰值,以降低温度峰值、减小降温阶段的温度收缩变形总量。

With the wide application of mass concrete,the analysis and control study of temperature stresses and temperature cracks are becoming more and more important.Now,taking a steel box arch bridge as an example,we use finite element software to establish a model,analyze the temperature and stress changes of the large volume concrete bearing and arch seat,and introduce its corresponding construction process and technology,and put forward the corresponding anti-cracking measures.The results show that the theoretical peak temperature of concrete in each bin of the bearing and arch base is between 43.5℃and 55.5℃when the mold temperature is 26℃,which is less than 65℃to meet the specification requirements;the theoretical main tensile stress of concrete in each bin of the bearing and arch base is between 1.09MPa and 2.28MPa during the warming period and 0.47MPa after the cooling stage under the mold temperature of 26℃.MPa-1.13MPa.During the construction process,the mold entry temperature should be lowered as much as possible to reduce the temperature peak in order to lower the temperature peak and reduce the total temperature shrinkage deformation during the cooling stage.