Safety conditions evaluation on suspended pipe section in a products pipeline

A 324 m-long suspended pipe section in a products pipeline was formed by flood. Based on traditional design code on stress, the evaluation on stress state of the suspended pipe section showed that the possible failure was not true against the actual condition; while, based on the design code on strain, evaluation on stress state of the suspended pipe section with consideration to elastic-plastic deformation capacity of pipe materials showed that the section was in a safe state with a biggest bending degree of 7.08 m, so basically it was in a true situation. A further analysis was taken on factors, affecting the strain ability of section possibly. Results showed that analysis with stress-based traditional design code on stress state of the section would get a conservative result. Therefore, it is suggested that the strain-based code should be used to utilize the plastic strain ability of pipe materials completely. Strain-hardening characteristics of pipe materials like yield strength, tensile strength and strain hardness indicators etc. have a significant influence on the maximum strain capacity that the suspended pipe section is born.