Estimating Deterioration in the Concrete Tie-Ballast Interface Based on Vertical Tie Deflection Profile: A Numerical Study

Details

• Creators:
  Yu, Hailing
• Corporate Creators:
  John A. Volpe National Transportation Systems Center (U.S.)
• Subject/TRT Terms:
  • Railroad ties
  • Concrete ties
  • Prestressed concrete ties
  • Ballast crib
  • Finite element method
  • Wire
  • Inspection equipment
  • Failure
  • Deflection tests
• Publication/ Report Number:
  JRC2016-5783
• Resource Type:
  Research Paper
• Geographical Coverage:
  United States
• Corporate Publisher:
  American Society of Mechanical Engineers
• Abstract:
  In ballasted concrete tie track, the tie-ballast interface can ; deteriorate resulting in concrete tie bottom abrasion, ballast ; pulverization and/or voids in tie-ballast interfaces. Tie-ballast ; voids toward tie ends can lead to unfavorable center binding ; support conditions that can result in premature concrete tie ; failure and possible train derailment. Direct detection of these ; conditions is difficult. There is a strong interest in assessing the ; concrete tie-ballast interface conditions indirectly using ; measured vertical deflections. ; This paper seeks to establish a link between the vertical ; deflection profile of a concrete tie top surface and the tie-ballast ; interface condition using the finite element analysis (FEA) ; method. The concrete tie is modeled as a concrete matrix ; embedded with prestressing steel strands or wires. The ; configurations of two commonly used concrete ties, one with 8 ; prestressing strands and the other with 20 prestressing wires, are ; employed in this study. All models are three-dimensional and ; symmetric about the tie center. A damaged plasticity model that ; can predict onset and propagation of tensile cracks is applied to ; the concrete material. The steel-concrete interface is ; homogenized and represented with a thin layer of cohesive ; elements sandwiched between steel and concrete elements. ; Strand- or wire-specific elasto-plastic bond models developed at ; the Volpe Center are applied to the cohesive elements to account ; for the interface bonding mechanisms. FE models are developed ; for both original and worn concrete ties, with the latter assuming ; hypothetical patterns of reduced cross sections resulting from ; abrasive interactions with the ballast. Static analyses of ; pretension release in these concrete ties are conducted, and ; vertical deflection gradients along tie lengths are calculated and ; shown to correspond well with the worn cross sectional patterns ; for a given reinforcement type.
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• Format:
  PDF
• Download URL:
  https://rosap.ntl.bts.gov/view/dot/12286/dot_12286_DS1.pdf
• File Type:
  [PDF - 2.05 MB]
• Collection(s):
  Volpe Center
• Main Document Checksum:
  urn:sha-512:9646653e6b19bb769dd26fc6972293f20aa35e6b1baca8d49c0cc711fafc73a8259232bc4e2411e1f1da0356fecc1917814e4ba7de6b8a66414f06515f3dc90c