Guidelines for Parallel-Plate Loading of Corrugated Steel Pipes Based on Finite-Element Analyses

This paper investigates the behavior of corrugated steel pipes (CSPs) under parallel-plate loading, aiming to provide guidelines for selecting the optimal length-to-diameter (L/D) ratio for cost-effective testing. Current standards lack specific guidelines for CSPs, and experimental results can deviate significantly from two-dimensional predictions based on thin ring theory, particularly for shorter pipes. The study uses finite-element analyses with the goal of capturing the vertical stiffness, the stress distribution, and the moment behavior. Use is made of a single-wavelength model of the corrugation with constraints to represent very long pipes, and without constraints to represent pipe segments of various lengths responding under parallel-plate loading. Results show that lateral displacement constraints significantly impact the pipe’s vertical stiffness, with large deviations (38.7%) from two-dimensional thin ring theory observed in cases where lateral displacement is unconstrained. A parametric study on CSPs with a 68×13 mm profile is conducted, providing insights into the vertical force ratio, the ratio of the vertical force to decrease the pipe diameter by a specific amount to that vertical force calculated using thin ring theory. A parametric study is conducted to quantify how vertical force ratio is affected by pipe length. Comparisons with experiments indicate that previous test data were underestimated by approximately 7%–16% under the new analysis. Recommendations are provided regarding pipe segment lengths that optimize effectiveness of the parallel-plate load test.