Time-Dependent Deformation of Concrete and Its Uncertainty

这项研究计划将导致改进的数学模型， 混凝土的徐变和收缩，其概率方面， 结构的影响。 本构关系，考虑到 应变软化，由于在可变湿度和断裂 收缩和热膨胀系数的应力依赖性，将 发展。 各种湿度条件下的蠕变试验和高温 温度将在一个独特的， 带温控的大型三轴扭转试验机。 还将测试小空心圆柱体的蠕变， 由于湿度变化而断裂的三轴扭转载荷 受到预应力的抑制。 开裂对整体干燥的影响 还将测量混凝土的扩散性。 数值算法 逐步有限元分析将制定和 数值验证，并在结构分析中的某些应用 将被证明。

This research program will lead to an improved mathematical model for creep and shrinkage of concrete, its probabilistic aspects, and its effects in structures. Constitutive relation, which takes into account strain-softening due to fracturing at variable humidity and stress-dependence of shrinkage and thermal expansion coefficients, will be developed. Creep tests at various moisture conditions and high temperatures will be conducted with six-inch cylinders in a unique, large triaxial-torsional testing machine with temperature control. Also tested will be creep of small hollow cylinders under triaxial-torsional load in which fracturing due to humidity variations is suppressed by prestress. Effects of cracking on the overall drying diffusivity of concrete will also be measured. Numerical algorithms for step-by-step finite element analysis will be formulated and verified numerically, and certain applications in structural analysis will be demonstrated.