The Flexural Behavior of Buried Steel and Composite Pipes Pulled Relative to Dense Sand: Experimental and Numerical Investigation

The flexural behavior of flexible buried pipelines subjected to lateral earth movements is investigated. Two types of pipeline materials, steel and then glass-fiber reinforced polymers (GFRP), are examined. Bending tests are conducted, where two parallel cables attached to a hydraulic actuator load the buried pipe. The study investigated three burial depth-to-diameter ratios (H/D = 3, 5, and 7) representing shallow to deep burial depths commonly used in energy pipeline construction. A three dimensional finite element model for this loading case has also been developed. Data from the numerical simulations are presented and compared to the experimental measurements. This paper provides an overview of the outcomes for this project. For example, while soil resistance was very similar for the two pipe types, the GFRP pipes demonstrated superior flexibility in longitudinal bending compared to the steel pipe. Furthermore, the finite element analyses were able to depict both this similarity in soil resistance, and the significant difference in flexural behavior of the two different pipe materials, the same phenomena observed during testing.