Load Rating Corrugated Metal Culverts with Shallow Soil Cover

Abstract

Culverts under existing roadways that do not meet current cover requirements are common. Even though they may have performed without any issues for decades, rating of many of them using current specifications and methodologies will result in a score that represents insufficiency, implying the culverts require posting. Thus, there is a question on the applicability of the existing approaches to the culvert structures under shallow cover. This dissertation established both 2D (plane strain) and 3D finite element analyses to predict the structural responses within metal corrugated culverts under truck loading and found significant difference between the results from these two analysis methods. A parametric study was performed for thirty-six different culvert models to develop a reduction ratio method correcting the 2D results to match the corresponding 3D results. After that, alternative flexure criteria for load rating shallow buried corrugated metal pipe and arch structures were implemented into finite element framework and generated accurate and conservative results compared with the rating factors from the cumbersome iterative procedure. Then, a simplified approach to load rating shallow buried corrugated metal culverts that emphasizes the available resistance of the structure rather than automatically rendering a rating factor less than one when the design cover requirement is not satisfied was developed and presented. Last, the rating outcomes calculated using the various available methods were assessed, compared and summarized and ultimately culminates in final rating recommendations for the shallow buried culverts.