A Theory for Track Maintenance Life Prediction
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Report Number: DOT/RSPA/DPB-50/81/25
Author(s): Selig, Ernest T., Chang, Ching S., Alva-Hurtado, Jorge E., Adegoke, Clement W.
Corporate Author(s): Department of Civil Engineering, State University of New York at Buffalo
Laboratory: Office of University Research
Date of Publication: 1981-06
Pages: 165
Contract: DOT-05-70058
DoD Task:
PB Number: PB81248007
Identifier: PB81248007
Abstract:
The objective of this study is to develop a methodology for predicting cumulative permanent deformation of track structures under traffic loading as a basis for maintenance life determination. A computer model named GEOTRACK was developed that represents the nonlinear elastic deformation of the track system. On the basis of a comparison of the elastic predictions with this model and the dynamic measurements form FAST, the model was considered to provide a reasonable representation of the track response. Available information on the elastic and inelastic properties of ballast and sub-grade materials under cyclic load was reviewed as a basis for selecting the form of material constitutive relationships required for the track performance predictions. Static and cyclic triaxial tests were then carried out on granite ballast with equivalent stress states determined from the GEOTRACK model. The method of predicting permanent strain accumulation in the ballast layer under the track is then described and predictions using this approach are illustrated by comparing them to measured inelastic strains in the FAST track.
Provenance: S. Kumar
Author(s): Selig, Ernest T., Chang, Ching S., Alva-Hurtado, Jorge E., Adegoke, Clement W.
Corporate Author(s): Department of Civil Engineering, State University of New York at Buffalo
Laboratory: Office of University Research
Date of Publication: 1981-06
Pages: 165
Contract: DOT-05-70058
DoD Task:
PB Number: PB81248007
Identifier: PB81248007
Abstract:
The objective of this study is to develop a methodology for predicting cumulative permanent deformation of track structures under traffic loading as a basis for maintenance life determination. A computer model named GEOTRACK was developed that represents the nonlinear elastic deformation of the track system. On the basis of a comparison of the elastic predictions with this model and the dynamic measurements form FAST, the model was considered to provide a reasonable representation of the track response. Available information on the elastic and inelastic properties of ballast and sub-grade materials under cyclic load was reviewed as a basis for selecting the form of material constitutive relationships required for the track performance predictions. Static and cyclic triaxial tests were then carried out on granite ballast with equivalent stress states determined from the GEOTRACK model. The method of predicting permanent strain accumulation in the ballast layer under the track is then described and predictions using this approach are illustrated by comparing them to measured inelastic strains in the FAST track.
Provenance: S. Kumar