混凝土构件温度与收缩应力敏感参数筛选方法

Screening methods for temperature and shrinkage stress sensitive parameters of concrete components

混凝土温度与收缩应力受多种因素影响,随着构件尺寸和浇筑龄期等改变,敏感参数会发生转化。在混凝土温度及收缩裂缝的理论计算、数值分析和裂缝控制工艺研究方面,若敏感参数判断不当,得到的分析结果会偏差较大,制定的裂缝控制工艺较难具有针对性。文中提出主导约束概念,即2种以上约束同时存在时,最大拉应力基本由主导约束决定,影响混凝土温度与收缩应力的敏感参数也存在于主导约束相关参数中。按照材料构成、温度梯度和外部约束3个不同约束形式建立混凝土构件模型,通过有限元数值计算,分析各个参数值在不同约束中的敏感特性,获得常见混凝土构件温度收缩应力的敏感参数。在此基础上结合参数取值及变化范围,形成影响常见混凝土构件温度收缩应力敏感参数的筛选方法。

The temperature and shrinkage stress of concrete are influenced by various factors,and sensitive parameters will undergo transformation with changes in component size and pouring age.In the theoretical calculation,numerical analysis,and crack control technology of concrete temperature and shrinkage cracks,if the sensitive parameters are not judged properly,the analysis results obtained will have a large deviation,and the formulated crack control technology is difficult to be targeted.The concept of dominant constraint is put forward in this paper.When two or more constraints exist at the same time,the maximum tensile stress is basically determined by the dominant constraint,and the sensitive parameter exists in the relevant parameters of the dominant constraint.A concrete component model was established based on three different constraint forms:material composition,temperature gradient,and external constraints.The sensitive characteristics of each parameter value under different constraints were analyzed through finite element numerical calculation,and the sensitive parameters of temperature shrinkage stress in common concrete components were obtained.On this basis,combined with parameter values and range of variation,a screening method for the sensitive parameters affecting the temperature shrinkage stress of common concrete components was formed.