Inspection, durability, and risk assessment of highway culverts

The objectives of this research were to reduce the risk of structural failure of short-span culverts and to initiate a comprehensive study that focuses on culvert inspection, durability, and risk assessment.; Sixty (60) culverts (25 metal, 25 concrete, and 10 thermoplastic) in Ohio were inspected based on ODOT and the ORITE proposed rating systems.; A multivariable regression analysis of the inspection data found that for the concrete culverts age and water pH were significant factors in both rating systems, while drainage flow abrasiveness was a significant factor in the ODOT system. For the concrete culverts, the ODOT system had a higher R2 value. The analysis of the metal culvert data found that the significant factors were age, rise, and culvert type. Drainage flow abrasiveness, pH, and flow velocity were also significant factors in the proposed rating system. The proposed rating system had a higher R2 value. Two artificial intelligence techniques, genetic algorithms and neural networks, were used to further improve the regression analysis results. Genetic algorithm didn't provide any improvement to the analysis. Neural networks significantly improved the regression analysis models by increasing the R2 value for all models.; Finite element simulations, using CANDE-89, were conducted for thermoplastic pipe culverts. Poor installation conditions were simulated to encounter actual field cases. Results of the simulations showed that introducing live loads during the early stage of embankment construction affect the performance of the pipe. As the live load increases the soil pressures and pipe deflections increase. Using good backfill material with relatively high compaction improved the performance of the pipe.; A simple yet comprehensive methodology was proposed for evaluating culvert risk assessment. This methodology was developed based on calculating the adjusted overall rating of each culvert for both the ODOT and ORITE proposed rating systems. Maintenance immediacy and inspection course of action proposed by NCHRP 251 (1982) was used for each adjusted overall rating.