Verification of ODOT's Load Rating Analysis Programs for Metal Pipe and Arch Culverts

The main objective of this study was to evaluate and improve the Ohio Department of Transportation's (ODOT's) current load rating procedures for corrugated metal culverts. This objective is achieved by testing 39 in-service culverts under static and dynamic loads, by evaluating the response of test culverts using available theoretical methods and numerical simulations, and by evaluating and advancing the current analysis tools and load rating methods based on the analytical and experimental evidence generated in this research. The experimental program was conducted to investigate the influence of several parameters on the field performance of culverts in Ohio. These parameters include backfill height, various static and dynamic load applications, and existing condition, size, shape, and other properties of corrugated metal culverts. Experimental results show that culvert deflections decrease nonlinearly with increasing backfill height. Deflections and strains were nearly zero in deep culverts with backfill height larger than 13 ft (4 m). Under static and dynamic truck loading, culvert deflections and strains increased significantly when the backfill height was less than about 6.5 ft (2.0 m). Responses of some of the test culverts were simulated using the two-dimensional finite element program CANDE. Deflections predicted from CANDE analysis were larger than deflections measured in the field. However, the moments and thrusts calculated from experimental strains were similar to those calculated using theoretical methods and CANDE. Experimental data and available theoretical studies were used to evaluate the current load rating methods. Recommendations are made to improve the analysis and evaluation procedures for corrugated metal culverts. Recommendations are based on an extensive review of load rating procedures and design practices, experimental data from 39 test culverts, and theoretical and numerical investigations. The recommended load rating procedures do not consider the effect of cover depth. New capacity reduction factors are introduced for culvert wall and seam, which require different appraisals for wall and seam during annual inspections. The authors recommend changes to rating factors for deep culverts and culverts subjected to low live load stresses.