THE INFLUENCE OF THE NON-DETERMINISTIC DESIGN MODEL OF THE REINFORCED BENDING ELEMENT

Abstract

Any design model, being a certain simplification of the real object, does not take into account some factors, which leads to inaccuracy of simulation results. Errors can arise and accumulate at all stages of modeling, it is difficult to predict them in the framework of the models used. Incomplete adequacy of models to the real object entails random nature of calculation inaccuracy.The reasons for the inaccuracy of the calculationmethods of building structures are various. The real structure is replaced by a system of rods, plates or volumetric elements, the material of structures is given idealized properties. These actions can be called physical modeling. Then write down a system of equations of internal stresses, strains, the resulting equations and dependencies are often simplifie.
 This stage can be called mathematical modeling. The combination of physical and mathematical models of the structure is called a design model of the structure. [9]Inaccurate calculation can lead to an insufficientlevel of structural reliability, which in turn leads to significant material and human losses. A corrected calculation makes it possible to reduce such losses and to realize the hidden reserves of construction.Note that in the design of a particular structure have to use different methods of calculation, which may have a significant inaccuracy; information about thevarious factors of construction is also necessary.And it is often difficult to determine which calculations should be specified first, as well as what level of background information is needed.The uncertainty of the calculation model can beestimated by testing or comparing the calculation results of the approximate model and the more accurate model. This uncertainty is taken into account by introducing a model reliability factor γd, which takes into account the uncertainty of the design scheme and other similar circumstances (e.g. sensitivity of the structure to local failure, initial imperfections or increased rate of wear) and is taken as amultiplier to the calculated load value.The model reliability coefficient can be dividedinto two multipliers that reflect the uncertainty of the design model regarding the load effects γsd and the load carrying capacity γRd.The coefficient γd (or γSd and γRd) reflects factors which are not taken into account directly in order to simplify the calculation provided for by the standards (consideration of creep and the influence of the joints' yielding, plastic properties of the material, etc.). In addition, these coefficients may take into account factors that are not considered by the calculation model at all (aggressiveness of the environment, the effect of corrosion, etc.).