Application of Reliability-Based Design Method of Pipeline Material Selection Available to Purchase

A certain inland pipeline is located in a cold area and traverses the alpine-cold and permafrost region. For design and selection of steel grade pipeline in such an area, the resistance of X52 and X60 pipes is calculated and analyzed using the reliability design method for the first time based on a comparison of conventional economy and technical schemes, combined with the analysis on pipe failure, reason, and type as well as the ultimate limit state. According to calculation and analysis, the overall resistance of X52 9.5mm pipe is higher than that of X60 8.7mm pipe, except for the equal resistance against excavation and puncture by a third party. This is especially true in regard to the ultimate tensile strain and compression strain, increasing by 17% and 31% respectively. By adopting the Monte Carlo method using certain parameters about pipe material, construction and operational maintenance, the failure probability of X52 and X60 pipes under corrosion as well as excavation and puncture by a third party is calculated and analyzed quantitatively. The result shows that the failure probability of X52, 9.5mm pipe is 2.61 ×10⁻⁴ times per kilometer per year which is much less than that of X60 8.7mm pipe (5.50 ×10⁻⁴ times per kilometer per year). Considering the safe reliability of pipeline, the X52 9.5mm pipe scheme is far superior to X60 8.7mm pipe scheme. Therefore the former scheme is recommended for design which only increases the cost by 1.5%.