Using FRP Wraps to Reinforce Buried Steel Pipelines Subjected to Permanent Ground Deformations: A Feasibility Study

In the present paper, the concept of using fiber reinforced polymer (FRP) wraps to reinforce buried steel pipelines subjected to permanent ground deformations is studied. For this purpose, the carbon-epoxy composite wrap is used on the API 5L grade X65 pipeline. Mechanical behavior of buried pipelines under strike-slip faulting is investigated using nonlinear finite element code ABAQUS. According to defined performance criteria, critical fault displacements for different thicknesses of the composite wraps and internal pressures are specified and percentage of increase in critical fault displacement compared to the non-wrapped condition is calculated. Using composite wraps with thicknesses of 1 mm and 9 mm on pressurized pipeline with diameter to thickness ratio of 96 increases the value of critical fault displacement up to 88% and 772%, respectively. According to results obtained from the present study, the concept of using FRP wraps to reinforce buried steel pipelines under permanent ground deformations can be implemented.