STUDY OF ANALYTICAL MODELS FOR TRACK SUPPORT SYSTEMS

Data on the dynamic responses of ballast, subballast, and subgrade of track sections at the Facility for Accelerated Service Testing track in Pueblo, Colorado, are compared with predictions from three available analytical models for track support systems. The response data include ballast strain, subballast strain, subgrade deflection, and subgrade stress. The analytical solutions are provided by (a) a model that combines Burmister's three-dimensional elasticity solution with a structural analysis model that solves for the tie-ballast reaction (MULTA), (b) a finite-element, three-dimensional model that has prismatic elements combined with a structural analysis model (PSA), and (c) a quasi-three-dimensional, finite-element model, in which a longitudinal two-dimensional analysis is followed by a transverse two-dimensional analysis (ILLI-TRACK). The results show that all three models can reasonably predict the behavior of the track system, provided that values for the material properties and model parameters are correctly specified. Each model has advantages and limitations compared with the others. ILLI-TRACK is the only model that can vary properties in the vertical, longitudinal, and transverse directions and also the only one having a nonlinear stress-strain representation. However, the accuracy of ILLI-TRACK is the only model that can vary properties in the vertical, longitudinal, and transverse directions and also the only one having a nonlinear stress-strain representation. However, the accuracy of ILLI-TRACK predictions is less certain because it depends on two empirical parameters, the effective tie-bearing length and the angle of distribution. The PSA model permits property variation in the transverse and vertical directions, but its computer costs are an order of magnitude greater than those for the other two models. The MULTA model is restricted to homogeneous layers of ballast and underlying materials, but it combines the features of both three-dimensionality and economy.

• Record URL:
  • http://onlinepubs.trb.org/Onlinepubs/trr/1979/733/733-003.pdf
• Record URL:
  • https://scholar.google.com/scholar_lookup?title=STUDY+OF+ANALYTICAL+MODELS+FOR+TRACK+SUPPORT+SYSTEMS&author=C.+Adegoke&author=C.+Chang&author=E.+Selig&publication_year=1979
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• Supplemental Notes:
  • Publication of this paper sponsored by Committee on Mechanics of Earth Masses and Layered Systems. Distribution, posting, or copying of this PDF is strictly prohibited without written permission of the Transportation Research Board of the National Academy of Sciences. Unless otherwise indicated, all materials in this PDF are copyrighted by the National Academy of Sciences. Copyright © National Academy of Sciences. All rights reserved
• Authors:
  • Adegoke, Clement W
  • Chang, Ching S
  • Selig, Ernest T
• Discussers:
  • Raad, L
  • Thompson, M R
• Conference:
  • 58th Annual Meeting of the Transportation Research Board
  • Location: Washington District of Columbia, United States
  • Date: 1979-1-15 to 1979-1-19
• Publication Date: 1979

Media Info

• Media Type: Print
• Features: Figures; References; Tables;
• Pagination: pp 12-20
• Monograph Title: Mechanics of track support, piles and geotechnical data
• Serial:
  • Transportation Research Record
  • Issue Number: 733
  • Publisher: Transportation Research Board
  • ISSN: 0361-1981

Subject/Index Terms

• TRT Terms: Analysis; Ballast (Railroads); Construction scheduling; Finite element method; Mathematical models; Mechanical properties; Soil mechanics; Subballast; Subgrade (Pavements); Validation
• Old TRIS Terms: Analytical techniques; Ballast mechanics; Fast track
• Subject Areas: Geotechnology; Highways; Railroads;

Filing Info

• Accession Number: 00315294
• Record Type: Publication
• ISBN: 0309029880
• Files: TRIS, TRB
• Created Date: Sep 16 1980 12:00AM