Retracted: “Evaluation of the Structural Integrity of Bell–Spigot Joints in Steel Gas Pipelines” [ASME Journal of Pressure Vessel Technology, 2022, 144(2), p. 021801; DOI: 10.1115/1.4052210

Abstract

Abstract The most common joining method in steel gas pipelines is welding; however, this method involves time-consuming, expensive manufacturing and assembly processes to ensure quality in operation. Bell–Spigot joints, which work by mechanical interference, have started to be used as an alternative joining method in steel pipes. Its use has increased due to its reduced assembly time and fewer postassembly inspection requirements. In this paper, the structural performance of Bell–Spigot joints in 16-in. steel pipe API 5 L X70 with fusion bonded epoxy coating for Natural Gas transmission pipeline are evaluated experimentally and by modeling. Test pieces were taken from the gas pipeline after 3 years of operation. Then, tensile pull-out and bending with hydrostatic pressure tests were performed to replicate operating conditions. Deformations, displacements, and the potential presence of leaks were monitored. Experimental results were compared with a finite element method model. Finally, an analytical model for the calculation of stresses and strains in the joint system's components was developed. It was determined that the tightness of the joint depends mainly on the radial interference and the interference length. A higher safety factor can be obtained at the Bell–Spigot joint than the base pipeline by optimizing the selection of joint design variables and the service loading conditions. If the interference pressure is lower than half of the operation pressure, the joint's mechanical strength will be higher or equal that the base pipe. Under interference pressure at operating pressure conditions, the most vulnerable component is the Bell due to the increased stresses acting on it, while the operating pressure relieves the stresses on the Spigot due to the interference pressure acting in the opposite direction. Under combined loading of internal pressure and external bending force, the base pipeline is the most susceptible component to fail. Therefore, the use of Spigot–Bell joints reduces assembly times and costs in steel gas pipelines while providing a safe and reliable joint under operating conditions.