Numerical Modelling of Corrugated Metal Arch Culverts with Shallow Cover

This study details the finite element modelling of two double-barrel, low-profile arch corrugated metal culverts with shallow cover. Instrumentation and load-testing was conducted in a previous study to measure the responses in terms of vertical deflection and inner fiber strain using a 381.3-kN (85.7-kips) load truck configured to the ALDOT LC-5 load specification, and the measured responses were used to validate the results of the numerical models in this study. The structural support from shallow buried culverts comes not only from the culvert itself but from the backfill soil as well, which makes it difficult to simply calculate the loads transferred and the response of the culvert structures. The objective of this study was to use numerical models to predict the structural behavior of the culverts due to external loading. 3D finite element models were created in Plaxis-3D and Abaqus, while 2D plane strain analysis was conducted in CANDE to simulate the load tests. Comparison of the field measured values to the numerical simulation results for the same load and measurement positions showed reasonable agreement in terms of trending and magnitude; however, the deflections predicted by the numerical analyses have been consistently higher than the measured values. The stresses estimated from the measured strain based on plane stress conditions also showed reasonable agreement with the calculated stresses from the FE analyses. Additionally, the validated modelling approach was then used to analyze a pipe culvert that could not be tested during the field-testing program, and the results were compared to those of the low-profile arch. The trends in the responses were similar; however, the vertical displacement from the pipe was relatively higher than that of the low-profile arch.