Simplified Approach for Modeling Loads Applied to Corrugated Steel Pipes Subjected to Parallel-Plate Loading

This study examines the three-dimensional finite-element modeling of corrugated steel pipes (CSPs) subjected to parallel-plate loading. Three different loading models are considered: Case 1, where a radially distributed load is applied to the crests of the corrugation with friction to simulate restraint against longitudinal movements under the loading plate; Case 2, where the radially distributed loads are applied without friction; and Case 3, where a concentrated load is applied at the crest of each corrugation together with friction. Cases 1 and 2 replicate a benchmark parallel-plate test and simulation, achieving agreement within 0.4%. Comparisons show that friction increases vertical stiffness by only 1.9%, and the difference between distributed and concentrated loading is just 1.8%. These findings demonstrate that the simplified concentrated load (Case 3) provides nearly identical stiffness to distributed radial loading. Overall, the current simulations consistently underestimate experimental stiffness by about 12%–13%, likely due to geometric imperfections in the tested pipe. The simplified method is therefore judged suitable for use as an efficient alternative for representing loads when modeling CSP response under parallel-plate loading.