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Federal Highway Administration Research and Technology
Coordinating, Developing, and Delivering Highway Transportation Innovations
| REPORT |
| This report is an archived publication and may contain dated technical, contact, and link information |
 |
| Publication Number: FHWA-HRT-18-053 Date: January 2019 |
Publication Number: FHWA-HRT-18-053 Date: January 2019 |
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The movement of superheavy loads (SHLs) on the Nation’s highways is an increasingly common, vital economic necessity for many important industries, such as chemical, oil, electrical, and defense. Many superheavy components are extremely large and heavy (gross vehicle weights in excess of a few million pounds), and they often require specialized trailers and hauling units. At times, SHL vehicles have been assembled to suit the load being transported, and therefore, the axle configurations have not been standard or consistent. Accommodating SHL movements without undue damage to highway infrastructure requires the determination of whether the pavement is structurally adequate to sustain the SHL movement and protect any underground utilities. Such determination involves analyzing the likelihood of instantaneous or rapid load-induced shear failure of the pavement structure.
The goal of this project was to develop a comprehensive analysis process for evaluating SHL movement on flexible pavements. As part of this project, a comprehensive mechanistic-based analysis approach consisting of several analysis procedures was developed for flexible pavement structures and documented in a 10-volume series of Federal Highway Administration reports—a final report and 9 appendices.(1–9) This is Analysis Procedures for Evaluating Superheavy Load Movement on Flexible Pavements, Volume Ⅴ: Appendix D, Estimation of Subgrade Shear Strength Parameters Using Falling Weight Deflectometer, and it presents an approach to estimate the shear strength parameters of a pavement’s subgrade layer based on nondestructive falling weight deflectometer measurements. This report is intended for use by highway agency pavement engineers responsible for assessing the structural adequacy of pavements in the proposed route and identifying mitigation strategies, where warranted, in support of the agency’s response to SHL-movement permit requests.
Cheryl Allen Richter, Ph.D., P.E.
Director, Office of Infrastructure
Research and Development
Notice
This document is disseminated under the sponsorship of the U.S. Department of Transportation (USDOT) in the interest of information exchange. The U.S. Government assumes no liability for the use of the information contained in this document.
The U.S. Government does not endorse products or manufacturers. Trademarks or manufacturers’ names appear in this report only because they are considered essential to the objective of the document.
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Technical Report Documentation Page
| 1. Report No.
FHWA-HRT-18-053 |
2. Government Accession No.
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3 Recipient's Catalog No.
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| 4. Title and Subtitle
Analysis Procedures for Evaluating Superheavy Load Movement on Flexible Pavements, Volume Ⅴ: Appendix D, Estimation of Subgrade Shear Strength Parameters Using Falling Weight Deflectometer |
5. Report Date
January 2019 |
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| 6. Performing Organization Code
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| 7. Author(s)
Hadi Nabizadeh (ORCID: 0000-0001-8215-1299), Elie Y. Hajj (ORCID: 0000-0001-8568-6360), Raj V. Siddharthan (ORCID: 0000-0002-3847-7934), Mohamed Nimeri (ORCID: 0000-0002-3328-4367), Sherif Elfass (ORCID: 0000-0003-3401-6513), and Murugaiyah Piratheepan (ORCID: 0000-0002-3302-4856) |
8. Performing Organization Report No.
WRSC-UNR-201710-01D |
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| 9. Performing Organization Name and Address
Department of Civil and Environmental Engineering |
10. Work Unit No. (TRAIS)
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| 11. Contract or Grant No.
DTFH61-13-C-00014 |
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| 12. Sponsoring Agency Name and Address
Office of Infrastructure Research and Development |
13. Type of Report and Period Covered
Final Report; August 2013–July 2018 |
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| 14. Sponsoring Agency Code
HRDI-20 |
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| 15. Supplementary Notes
Nadarajah Sivaneswaran (HRDI-20; ORCID: 0000-0003-0287-664X), Office of Infrastructure Research and Development, Turner-Fairbank Highway Research Center, served as the Contracting Officer’s Representative. |
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| 16. Abstract
The movement of superheavy loads (SHLs) has become more common over the years since it is a vital necessity for many important industries, such as chemical, oil, electrical, and defense. SHL hauling units are much larger in size and weight compared to standard trucks. SHL gross vehicle weights may be in excess of a few million pounds, so they often require specialized trailers and components with nonstandard spacing between tires and axles. Accommodating SHL movements requires the determination of whether a pavement is structurally adequate and involves the analysis of the likelihood of instantaneous or rapid load-induced shear failure. As part of the Federal Highway Administration project, Analysis Procedures for Evaluating Superheavy Load Movement on Flexible Pavements, a novel methodology to estimate in-situ shear strength parameters (angle of internal friction (ϕ) and cohesion (c)) of a pavement’s subgrade (SG) layer was developed and verified. The approach is based on nondestructive falling weight deflectometer (FWD) testing undertaken at multiple load levels. The validity of the proposed approach was explored using numerical simulations of FWD tests, as well as FWD data collected from large-scale experiments on full-scale pavement structures and Accelerated Pavement Testing facilities. It was found that the proposed FWD-based methodology was able to reasonably estimate ϕ and c of an SG layer with softening behavior. Such results were achieved when the highest induced deviator stress level in the SG layer under the FWD loading was in excess of approximately 30 percent of the deviator stress at failure obtained with the proposed procedure. |
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| 17. Key Words
Flexible pavement, superheavy load, large-scale experiment, FWD, LWD, shear strength |
18. Distribution Statement
No restrictions. This document is available to the public through the National Technical Information Service, Springfield, VA 22161. |
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| 19. Security Classification (of this report) Unclassified |
20. Security Classification (of this page) Unclassified |
21. No. of Pages
47 |
22. Price
N/A |
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| Form DOT F 1700.7 (8-72) | Reproduction of completed page authorized |
