文章基本信息

标题：Development of the procedure for the estimation of reliability of reinforced concrete beams, strengthened by building up the stretched reinforcing bars under load
本地全文：下载
作者：Roman Khmil ; Roman Tytarenko ; Yaroslav Blikharskyy 等
期刊名称：Eastern-European Journal of Enterprise Technologies
印刷版ISSN：1729-3774
电子版ISSN：1729-4061
出版年度：2018
卷号：5
期号：7
页码：32-42
DOI：10.15587/1729-4061.2018.142750
语种：English
出版社：PC Technology Center
摘要：We studied the stresses state of rectangular reinforced concrete beams strengthened by building up the stretched reinforcing bars under the action of load. We developed two principal methods for assessing the reliability of the strengthened beams based on various regulatory documents. According to the developed methods, we established reliability of the tested structures and obtained the results of qualitative and quantitative indicators for reliability, specifically, reliability indices and probabilities of failure-free operation. We analyzed an effect of the considered stochastic parameters of the reserve of bearing capacity of normal cross sections of strengthened beams on a general reliability estimate.The establishment of actual indicators of reliability of beams strengthened under the action of load will make it possible to approach the issue of reconstruction of elements of buildings and structures more efficiently and economically. In particular, this relates to strengthening of bending of reinforced concrete elements under operation. In addition, the obtained results of reliability study make it possible to operate with those variable parameters that have the maximum influence on variance of the limiting bending moment of beams studied with sufficient accuracy of calculation.The developed principal methods for assessing reliability make it possible to design strengthened reinforced concrete bending elements with the assigned level of reliability (efficiency of solutions) ‒ probability of failure-free operation, which may be also the subject for further research. Finally, the obtained results make it possible to approach the choice of the strengthening method more effectively.Thus, we propose a methodology adapted to the current design standards of Ukraine for assessment of reliability. It includes a relatively simple mathematical calculation apparatus. Moreover, in contrast to the results of earlier studies, the obtained values of reliability indicators are clear, since they have a distribution close to proportionality depending on a load level and a diameter of reinforcement extension. Thus, for reliability indices βi, the range of values was from 3.35 to 3.45, and for the probability of failure-free operation P(β)i ‒ from 0.999596 to 0.999720 (towards increasing the reliability level at a larger diameter of the reinforcement of extension and a load level at the moment of strengthening). The discrepancy between identical values of indices found in accordance with engineering and deformation models of calculation was about 8 % only. This fact allows the application of the developed methodology in the design practice. Therefore, taking into consideration the lack of research in the field of assessment of reliability of the reinforced concrete bending elements strengthened under the action of load, we can state that the results obtained are relevant
关键词：reinforced concrete beam;strengthening;stochastic parameters;reliability assessment;probability of failure-free operation;level of loading