Congestion due to roadway and pedestrian traffic, especially between classes, at this intersection forced Southern Illinois University at Carbondale (SIUC) to consider options for a safer crossing. Because this location is adjacent to the Engineering Building, University Faculty and Maintenance staff came together with a vision to create an innovative structure using state-of-the-art materials that could also be used as a research project for College of Engineering and Sciences faculty and students. They settled on a bridge that would use fiber reinforced polymer (FRP) members and selected Modjeski and Masters to assist with the challenging project.
SIUC engineering staff had obtained a prototype FRP arch that they wished to use for the main span over Lincoln Drive, but M&M considered numerous options for the span. M&M completed a full evaluation of the main span options, including a thorough study of dynamic loading conditions to determine a span type that, due to the inherent flexibility of FRP, could resist vibration induced by pedestrian and wind loads. Ultimately, an arched truss, which would utilize the prototype arch member, with deck girder approach spans was proposed as the best fit for the University’s needs.
The main span was designed as an 82-foot FRP truss span with a 10-inch FRP composite deck. Symmetric approach spans consisted of a 20-inch thick FRP composite deck span, 19 feet in length, and a 36-inch deep FRP composite beam span with a 6-inch thick FRP composite deck, 41 feet in length. The structure was designed to be supported on traditional masonry substructure. Unfortunately, due to a decrease in available funding, the project was never constructed.
|Lanes of Structure