Риск-ориентированный подход к дефектности железобетонных конструкций

Abstract

During the operation of buildings and structures for various purposes, there are cases of damage and collapse of structures, which reduces the personnel safety. An analysis of the destruction of load-bearing capacity building structures or the causes of accidents occurrence at the industrial facilities showed that the prerequisites were laid mainly at the stage of manufacturing structures or during the construction process. Experience of incoming inspection of the reinforced concrete products shows that structures often arrive at the construction site with deviations in concrete strength from the design class. Formally, such a design should be rejected, and a new one ordered instead. However, the bearing capacity of the reinforced concrete structure can be maintained. And the problem arises of determining the possibility of using reinforced concrete structures with various defects arriving at the construction site in conditions of limited logistical capabilities. The object of study was the construction of supports (prestressed reinforced concrete column with a metal head) for the equipment of open switchgears with a capacity of 110 kV. To solve the problem, a risk-oriented approach was applied. Since there are no requirements for the levels of acceptable risks in the design standards, the risks of all participants in the process of construction and operation of the object were assessed — the contractor, the customer, who in the task under consideration also performs the functions of the operating organization, the manufacturer of reinforced concrete products according to three criteria (Wald, Savage, Laplace) with two approaches — under conditions of uncertainty and multi-criteria, and under risk conditions (taking into account subjective probabilities). The concept of risk was interpreted as the product of the probability and consequences of the occurrence of adverse events. For none of the participants, none of the criteria indicated that the optimal strategy was «Return the rack to the manufacturer and obtain a defect-free rack». Therefore, the formal rejection of a reinforced concrete product with minor defects, provided that the bearing capacity is observed, is not optimal.