Ageing and Static Reliability of Concrete Structures under Temperature and Mechanical Loading

The contribution presents some aspects of the static reliability of concrete structures under temperature effects and under mechanical loading. The mathematical model of a load-bearing concrete structure was performed using the FEM method. The temperature field and static stress that generated states of stress were taken into account. A brief description of some aspects of evaluation of the reliability within the primary circuit concrete structures is stated. The knowledge of actual physical and mechanical characteristics and chemical composition of concrete were necessary for obtaining correct results of numerical analysis. Studied problems were divided into a number of fields and worked out in details: 1. Verification of contemporary physical and mechanical characteristics of concrete (input parameters of the FEM models). 2. Checking of the concrete microstructure and verification of the grade and kind of possible microstructure changes. 3. Experimental verification of the boundary conditions from point of view of the temperature field and the radiation stress. 4. Setting up a mathematical model of the structure for an examination of the interaction of temperature and static stresses (finite element method, software ANSYS) in two alternatives: a) Macro-model representing the essential part of concrete structures in the proximity of the reactor, b) Model of extremely stressed parts of the concrete structure (a part of the macro-model)