考虑混凝土龄期及弹塑性徐变的大体积混凝土温度应力研究

针对目前大体积混凝土工程上常用的混凝土徐变度是考虑了施加荷载时混凝土龄期的粘弹性模犁,在较大的变温荷载作用下计算的温度应力往往过大,与实际不符.将常用的混凝土弹性徐变模型推广为弹塑性徐变模型,建议在弹性徐变模型的基础上串联一个混凝土强度参数及粘滞系数随龄期增长的Bingham元件来考虑混凝土的塑性流变,推导了弹塑性徐变温度应力仿真分析的隐式和显式算法公式,并研制了相关的程序.工程实例仿真分析表明,作者建议的考虑混凝土龄期的弹塑性徐变模型是可行的,其计算的温度应力较弹性徐变模型的计算值更符合实际.

Study of Thermal Stress for Mass Concrete Considering Concrete Age and Elastic-plasticity Creep

In view of the fact that the creep degree of concrete commonly used in mass concrete engineering is actually a visco-elastic model which considers concrete age under load. It is inconsistent with the reality because the thermal stress calculated by visco-elastic model is bigger under big temperature load. The elastic creep formula is promoted instead of elasto-plastic creep formula in this paper; it is proposed that the plastic creep should be considered through linking a Bingham series whose strengthen parameter and viscosity factor increase as the concrete age increases on the basis of elastic creep model; an elastio-plastic creep formula with implicit and explicit arithmetic are deduced as well as consider plastic creep; the relative programs are developed based on the formula. Analysis of engineering examples shows that the elastio-plastic creep formula offered in this paper is feasible, and the values calculated by it is more reasonable than the elastic creep one.