Load Testing and Rating of a Concrete Arch Bridge

The bridge carrying 19th Street over Yellow Creek in Middlesboro, Kentucky, is a 16.8 m (55′) long and 14.8 m (48′–6″) wide concrete arch bridge constructed in 1943. Structural plans for the bridge are unavailable. This paper details the methods used to determine the safe live load carrying capacity of the bridge based on diagnostic load testing. Load Factor Ratings were determined for legal truck loads in accordance with the AASHTO Manual for Bridge Evaluation utilizing a 2D Finite Element model and then adjusted based on field measured strain data. Despite substandard theoretical load ratings, load testing revealed that the bridge has sufficient capacity to carry legal traffic without restriction.