Field testing of railroad flatcar bridges

Field testing of multiple span railroad flatcar bridges on low volume roads

“…To determine the safe load carrying capacity of the multiple span RRFC bridges tested in this investigation, an inventory load rating was determined for each of the three RRFC bridges. For consistency with previous reports [7] and with the field information gathered, the allowable stress method was used to determine the rating factor. Using the AASHTO Manual for Condition Evaluation of Bridges (Rating Manual) [12], the rating factor is equal to:…”

“…For RRFC bridges, the live load effect on a member, L, was determined by multiplying the maximum live load effect by a distribution factor which represents the percentage of the live load resisted by the member being rated. For consistency with previous reports [7], this distribution factor is assumed to be the same distribution factor used in the simplified design procedure (Equation 6.1). The distribution factor to determine the live load effect on a member is:…”

“…Figure 4 7,. 21 BDIs were placed at four different cross sections along the bridge; seven string potentiometers were located on the midspan cross section, also shown in the figure.String potentiometers were attached to the bottom of the main girders midspan of the center span as well as to the exterior girders of the bridge(Figure 4.7f).…”