Method of reliability assessment of arctic pipelines in the space of loads

• Main Authors: Opeyemi, D., Timashev, S. A., Bushinskaya, A. V., Patelli, E., Beer, M., Опиеми, Д., Тимашев, С. А., Бушинская, А. В., Пателли, Е., Бир, М.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Уральский федеральный университет 2017
• Subjects: PIPELINE; SPACE OF LOADS; RELIABILITY; RELIABILITY ASSESSMENT; SURFACE CORROSION; NATURAL AND TECHNOLOGICAL LOADS; ТРУБОПРОВОД; ПРОСТРАНСТВО НАГРУЗОК; НАДЕЖНОСТЬ; ОЦЕНКА НАДЕЖНОСТИ; ПОВЕРХНОСТНАЯ КОРРОЗИЯ; ПРИРОДНЫЕ И ТЕХНОЛОГИЧЕСКИЕ НАГРУЗКИ; Arctic; permafrost; Tundra
• Online Access: http://elar.urfu.ru/handle/10995/57674; https://elibrary.ru/item.asp?id=32656184; https://doi.org/10.15826/rjcst.2017.1.007

Arctic pipelines (PL) are located north of the 60th parallel. The main factors that characterize features of such pipelines are the climatic conditions in their areas of installation. Arctic pipeline routes pass through tundra with dwarf vegetation, marshes, and large areas with permafrost lenses, in watery and swampy areas with unique geological and hydrological conditions. The absolute difference of temperatures ranges from –56 degrees Centigrade in winter to 34 Centigrade in summer; and strong winds with speed over 40 m/s. Under these conditions, reliability and safety assessment of pipelines is associated with many principal difficulties, one of which is the need to take into account the simultaneous action (a combination) of many natural and technological loads on the pipeline infrastructure, which are random by nature and can be adequately described only by stochastic processes. Currently, reliability assessment of such systems is not performed due to lack of valid calculation methods. In this paper a description is given of the first stage of assessing reliability of a pipeline subject to a combination of loads described as random Markov processes. This method, developed by S. A. Timashev in [1], a. k.a. assessment of reliability in the space of loads, assumes the ability of constructing admissible areas in this load space with respect to different limit states. The method is applied to a segment of an above ground arctic oil pipeline with surface corrosion type defects, subjected to a combination (simultaneous action) of four loads: 1) dead weight of the pipe with insulation and oil being pumped, 2) operating pressure, 3) wind load, and 4) exposure to a uniform wall thickness thinning. The pipeline is considered as a continuous multi-bay thin wall cylindrical beam. The pipeline design is performed according to the (conditional) limit state which is reached when the equivalent stresses in pipe wall reach the yield stress of pipe material. The main purpose of the presented work is reliability assessment of ...