Unidirectional CFRP Reinforcement in Buried Pipelines: Performance Limits at Strike‐Slip Fault Crossings

ABSTRACT The mechanical behavior and seismic performance of buried pipelines have been extensively investigated in recent years. However, to the best of the author's knowledge, research studies on the performance limits of these pipelines, particularly wrapped with unidirectional carbon fiber–reinforced polymer (CFRP) remain limited. This study examines the performance limits of buried steel pipelines reinforced with unidirectional CFRP as they cross strike‐slip fault lines. The investigation focuses on the influence of fault angles and evaluates the effectiveness of CFRP reinforcement under these conditions. CFRP material properties were experimentally characterized by standardized tensile and three‐point bending tests. A three‐dimensional finite element model was developed using ABAQUS to simulate soil‐pipe interaction across fault crossing scenarios with angles ranging from 0° to 40°. The study also considers various CFRP configurations, including single‐layer ( t = 1.5 mm) and four‐layer ( t = 6.0 mm) wrappings, with fiber orientations of 0° and 90°. Damage mechanisms such as local buckling, ovalization, and composite rupture were analyzed to assess performance limits under different fault angles. The results demonstrate that even a single layer of CFRP wrapping significantly enhances the displacement capacity of the pipeline compared to conventional steel pipelines. Reinforced configurations showed reduced stress concentrations and more ductile behavior under both tensile and compressive loading. These findings offer valuable insights into optimizing CFRP retrofitting strategies and enhancing the resilience and safety of buried pipeline infrastructure in seismically active regions.