Load Rating for Corrugated Metal Culverts under Shallow Cover Depths

The accuracy and applicability of existing methodologies and tools for load rating of corrugated metal culverts under shallow cover were thoroughly investigated through numerical modeling and field testing. The basis of three existing spreadsheet rating tools were investigated. Two existing culverts that are more than 80 years old and whose cover over the crown is significantly less than current design and construction requirements were instrumented and load tested. The test data was then used to improve the accuracy of the analytical rating factors using the approach defined in the AASHTO Manual for Bridget Evaluation. The plane strain finite element program CANDE that was developed specifically for culvert analysis and design and is widely used, plus two general-purpose finite element software, Abaqus and Plaxis, were extensively employed to understand the soil-structure interaction phenomena and assess culvert rating methodology. Recommendations for addressing the deficiencies of the existing \u201csimplified\u201d spreadsheet tools for low cover situations were developed and incorporated into a new spreadsheet-based tool