With the aging infrastructure of pipelines in the United States, the demand for cost-effective and reliable repairs is rapidly increasing. The potential repercussions of numerous crack anomalies found during inspection poses a threat to pipeline operators’ risk management and asset integrity. By studying the effectiveness of composites for crack reinforcement, ADV Integrity and its JIP partners hope to give operators an additional tool at their disposal for mitigating pipeline threats.
Members of the JIP in addition to ADV Integrity include 3 composite manufacturers and 8 pipeline operators. Ryan Holloman, Engineering Staff Consultant for ADV Integrity who specializes in fracture mechanics, is the lead engineer on the project team. He said, “Ultimately, we hope to provide another technology to use as opposed to steel sleeves. At the end of the day, it will hopefully reduce operational costs.”
According to Holloman, the scenarios in which composites could be the most beneficial are when a crack occurs in irregular pipe geometry and a wet lay-up install is less cumbersome. Unlike steel sleeves which often go beyond the crack region due to laminations in the steel, composite repairs will require significantly less repair area for the same defect. Finally, steel sleeves require large amounts of pressure to conform to a pipe prior to welding, which can introduce bending stress on an axial crack. In all of these situations, composites could be the better alternative in terms of cost and reliability.
The analysis performed as part of the JIP include 37 specimens which originated from 2 retired pipeline materials that were donated by partner companies. The study simulates fatigue by cycling the specimens prior to repair to initiate a crack. After being repaired, the specimens are cycled again to demonstrate their ability to permanently repair cracks in pipelines. ADV Integrity has established open communication channels with the Pipeline and Hazardous Materials Safety Administration (PHSMA) throughout the study to ensure compliance with regulatory standards.