LOW-COST BRIDGES USING RAILROAD FLATCARS

The Bridge and Engineering Center of the Iowa State University has undertaken research to make bridges safer and to build them at a lower cost. This article's focus is on the investigation of the feasibility of using railroad flatcars as the superstructure for bridges on low volume roads. The research has demonstrated that flatcars are easy to install, they can be used on current or new abutments, are available in various lengths, and are relatively inexpensive. To test the constructability, adequacy, and relative economy, two flatcar demonstration bridges have been designed and constructed. Strain and deflection data from field tests have validated the bridge behavior predicted by the analytical models of each bridge. The engineered flatcar bridges have low live-load stresses and deflections that are below the limits set in the AASHTO specifications.