Engineering method of calculating the reliability of hydraulic structures

Abstract

The introduction of the methodology of reliability theory into the practice of designing, constructing, and operating hydraulic structures makes it possible to more well-foundedly solve problems of optimization of engineering decision being made. In this case, the quantitative indices of reliability, along with cost and technological factors, perform the role of optimization criteria. The considerable labor intensity of probabilistic calculations prevents their wide use. We will examine some techniques of simplifying the method of calculating reliability.The random variability of the characteristics of effects, materials, foundation rocks, as well as of the parameters of the initial state and construction and operating conditions determine the nonzero numerical value of the probability of failure P (or damage) of structures during a fixed time (for example, during a year or period of operation T). The probability of no-failure operation (i -P) is taken as the index of reliability [i, 2, 1.0].The probabilistic nature of the occurrence of limit states of hydraulic structures is taken into account by design standards when designating the probability of the design characteristics of effects and properties [3~ However, the deterministic form of such consideration leads to the necessity of regulating the limited number of design cases related to individual types of limit states and determining the combination and level of design effects and characteristics of the properties. As a consequence of this, noneconomical or extremely risky design decisions are possible. The indicated shortcomings are eliminated, as is known [i, 2, 7-10], by using a single index of the state of the structure -the probability of its no-failure (reliable) operation R.