On rationing the reliability of crack opening normal to the longitudinal axis of reinforced concrete bent elements from the condition of permeability limitation

Abstract

The use of a probabilistic method for calculating building structures is impossible if there is no information about the maximum values of the probability of failure-free operation. These values are assigned or determined differentially depending on the type of calculation – strength, deformations, etc. The purpose of this article is to establish a reasonable limit value for the probability of trouble–free operation in the width of crack opening of bent reinforced concrete structures from the condition of permeability limitation. Only the opening width of cracks normal to the longitudinal axis of the element was considered.

The establishment of the maximum value of the probability of failure-free operation was carried out using the probabilistic optimization method, with some changes: instead of the initial cost, a conditional initial cost was used. The magnitude of the economic consequences was taken as a fraction of the conditional initial cost in the range from 0.1 to 2.0. The probability of trouble-free operation was calculated on the assumption that all the initial parameters of the design and external influences are distributed according to the normal law. All the necessary initial data for calculations were adopted on the basis of regulatory documents and scientific literature devoted to the problem of reliability of building structures.

As a result of calculations, the maximum values of the probability of trouble-free operation were obtained, depending on the long and short crack opening. The calculated values are approximately in the range from 0.93 to 0.999, depending on the magnitude of economic losses. The values do not depend on the duration of the crack opening width. The obtained values are recommendations that can be used in the probabilistic method of calculating reinforced concrete structures.