This bridge is a unique structural system in that the north and south bridges are composed of completely different structure types, yet they are connected together and share roadway load paths. The south bridge was the original structure built in the 1920s and consists of a deep reinforced concrete truss, which in itself is unique. The north structure was built in 1940s using a more conventional steel girder bridge construction method. Initially the two bridges were independent parallel structures, but at a later date the decks were combined to create a single bridge such that load could be transferred between the two structures.
Determination of that load transfer and how the structures interacted was a very complex process because the span lengths were different, and the structures had vastly different stiffness. BDI was contracted by the DOT to perform load testing, structural analysis, and load rating on both structures. The goal was to determine safe load carrying capacity and determine the load interaction throughout the complex structural system. Results from this load test were to provide direct load rating reporting and for long-term asset management of an important structure in the city.
