Details:

Creators:
Yu, Hailing
Corporate Creators:
John A. Volpe National Transportation Systems Center (U.S.)
Subject/TRT Terms:
[+]
Ballast Crib Concrete Ties Deflection Tests Failure Finite Element Method Inspection Equipment Prestressed Concrete Ties Railroad Ties Wire
Publication/ Report Number:
JRC2016-5783
Resource Type:
Research Paper
Geographical Coverage:
United States
Corporate Publisher:
American Society of Mechanical Engineers
NTL Classification:
AGR-INFRASTRUCTURE-Railroads;NTL-RAIL TRANSPORTATION-Rail Safety;NTL-RAIL TRANSPORTATION-RAIL TRANSPORTATION;
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.


Format:
PDF
Collection(s):
Volpe
Main Document Checksum:
[+]
urn:sha256:91f056cfa783ccad861a7cdd4645e61bf1e36820b5f2150c1d5af1d74da54c3f
Download URL:
https://rosap.ntl.bts.gov/view/dot/12286/dot_12286_DS1.pdf
File Type:

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