Improvement of the method of probability evaluation of the failure-free operation of reinforced concrete beams strengthened under load

Abstract

The article is dedicated to the study of the load level effect on failure-free operation probability of undamaged rectangular cross-section reinforced concrete beams when their strengthening by the tensile steel reinforcement increasing. The presence of the load level simulates the real structure exploitation conditions at their strengthening. The validation of basic and improved reliability evaluation methods on real beam samples allowed receiving the recommended failure-free operation values P(β). Both techniques are adapted to national standards for the reinforced concrete structure design. The difference between the techniques is the operating method of the random parameter of the load level at the moment of amplification. According to the results of approbation the comparative analysis of the received results is carried out – depending on additional steel bar diameter and the load level at the moment of amplification. The practical significance of the article results is in use of both existing and advanced methods of the probabilities of failure-free operation estimation of reinforced concrete bended elements, strengthened by addition of the stretched steel reinforcement under different load levels, in particular, for accepting higher design levels of reliability.