Load-Rating Procedures for Railroad Flatcars Repurposed as Sustainable Highway Bridges

Abstract

Many county highway agencies have explored different options for economical replacement of existing deteriorating bridges. Using retired railroad flatcars (RRFCs) as the bridge superstructure is an attractive and sustainable option for some owners with very limited budgets and where traffic volumes are low. Using RRFCs is also environmentally attractive because they are 100% recyclable. Previous research focused on the development of guidelines to address the uncertainty that exists when load rating these types of structures. Those guidelines were based on field testing conducted on existing RRFC bridges. However, questions remain about the response under loads higher than could be easily achieved during the field testing. Further, although most RRFC bridges utilize timber decks or thin plate decks covered in bituminous material, there is evidence suggesting that installing a traditional composite RC deck is actually more economical and greatly improves load distribution. This paper presents the results of laboratory testing of a RRFC bridge and the revision of previously proposed load-rating guidelines for RRFC bridges constructed with composite concrete decks, using experimental data and finite-element analysis.