Technical Reports

The Effect of Imperfections on the Vertical Buckling of Railroad Tracks

  • 01
  • Jul
  • 1976
AUTHOR: Federal Railroad Administration; Yehia M. El-Aini
SUBJECT: Track, Tracks & Structures, Track/Train Interactions
KEYWORDS: Buckling; Vertical buckling
ABSTRACT: This report deals with an analytical prediction of the effect of geometric imperfections on the post-buckling characteristics of railroad tracks. The analysis is restricted to the case of vertical track buckling due to constrained thermal expansion in which the track is assumed to lift itself up over a finite span. The imperfections are categorized into two cases. Case (A) in which the region of imperfection is larger than the span of lift-off and Case (B) in which the imperfection region is smaller than the span of lift-off. It is shown that while a perfectly straight track does not exhibit bifurcation points from the undeformed state, the imperfect track does and that the bifurcation temperature in Case (A) is lower than in Case (B) for the same ratio of imperfection amplitudes reduces the bifurcation temperatures significantly. It is found that the bifurcation temperature as well as the safe temperature increase are higher for heavier tracks.