Development of Load Rating Procedure for Railroad Flatcar Bridges through Use of Field Instrumentation. II: Procedure Development

Abstract

Many state and county highway agencies are often forced to develop innovative and economical replacement strategies for deteriorated bridges. One such option is to use a retired railroad flatcar (RRFC) for a bridge superstructure. Many states have found RRFCs to be successful and economical alternatives to more traditional structural systems. Although the performance of RRFCs has been satisfactory, there is little to no guidance in the AASHTO specifications for load rating these structures. This inexperience has led some to take overly conservative approaches when rating these bridges for strength and fatigue. This paper, the second of two companion papers, presents the development of proposed load rating guidelines for RRFC bridges. The guidelines were developed based on previous research found in the literature and through the use of controlled load testing of RRFC bridges as presented in the first companion paper.