This research investigated the dynamic live load impact on older long span steel truss railroad bridges, with special consideration for the effects of the higher train speeds. The study and investigation were based on analytical/ computational (finite element) modeling/analysis and field testing on an existing bridge. The specific objectives of this study were: (1) Develop an accurate finite element model of an existing long span truss bridge selected for this study, (2) Field testing of the subject bridge with actual trains of varying consists, axle loads, axle spacings and speeds traveling over it, and (3) Compare the results from the analytical/computational model with the field test results. Additional tasks included verifying the model and developing a procedure to help understanding the effects of train speeds on dynamic impact factors for the bridge, especially at train speeds higher than the current allowable operating speed limit. The objectives of the project were fully achieved with work performed in two stages.

The final report is available.