【摘要】 早期混凝土由于水化反应都会产生体积变化。如果体积变形受到约束就会产生应力,一旦超过混凝土的抗拉强度就会产生裂缝。由于早期混凝土的力学性能是随时间变化的,特别是徐变,它不仅与加载时间有关而且同时随龄期而变化,因此计算早期混凝土结构应力是较为复杂的问题。有限单元法不仅可以考虑混凝土刚度的变化,而且可以考虑温度、徐变、收缩等因素。本文利用初应力法对通用有限元软件ANSYS进行了二次开发,通过工程实例计算了高层建筑地下室侧墙早期混凝土应力的变化过程,并提出了相应的抗裂措施。更多还原

【Abstract】 All concrete structures are exposed to volume changes caused by hydration reactions in the early age.If the volume changes are restrained,stresses is generated which will cause cracking when it overcomes the tensile strength.As the mechanical properties of early age concrete vary with time,especially the creep degree depends on the time elapsed and the time at loading,to calculate the stress of concrete structure is a complex nonlinear problem.The finite element method(FEM) can take account of the evolution of the stiffness properties,the development of thermal strain,creep,shrinkage and so on.In this paper,a general approach for numerically simulating this type of behaviour is presented firstly.Then,how to solve this problem is introduced by the general finite element software ANSYS using the Initial Stress Method.Finally,a detailed description of an example calculation that demonstrates the potential of the numerical simulation strategy follows.更多还原