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Publication Number:  FHWA-HRT-18-053    Date:  January 2019
Publication Number: FHWA-HRT-18-053
Date: January 2019

 

Analysis Procedures for Evaluating Superheavy Load Movement on Flexible Pavements, Volume V: Appendix D, Estimation of Subgrade Shear Strength Parameters Using Falling Weight Deflectometer

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FOREWORD

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.(19) 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.

Quality Assurance Statement

The Federal Highway Administration (FHWA) provides high-quality information to serve Government, industry, and the public in a manner that promotes public understanding. Standards and policies are used to ensure and maximize the quality, objectivity, utility, and integrity of its information. FHWA periodically reviews quality issues and adjusts its programs and processes to ensure continuous quality improvement.

 

Technical Report Documentation Page

1. Report No.

FHWA-HRT-18-053

2. Government Accession No.

 

3 Recipient's Catalog No.

 

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

6. Performing Organization Code

 

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

9. Performing Organization Name and Address

Department of Civil and Environmental Engineering
University of Nevada
1664 North Virginia Street
Reno, NV 89557

10. Work Unit No. (TRAIS)

 

11. Contract or Grant No.

DTFH61-13-C-00014

12. Sponsoring Agency Name and Address

Office of Infrastructure Research and Development
Federal Highway Administration
Turner-Fairbank Highway Research Center
6300 Georgetown Pike
McLean, VA 22101

13. Type of Report and Period Covered

Final Report; August 2013–July 2018

14. Sponsoring Agency Code

HRDI-20

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.

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.

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.
http://www.ntis.gov

19. Security Classification
(of this report)

Unclassified

20. Security Classification
(of this page)

Unclassified

21. No. of Pages

47

22. Price

N/A

Form DOT F 1700.7 (8-72) Reproduction of completed page authorized

 

 

 

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Turner-Fairbank Highway Research Center | 6300 Georgetown Pike | McLean, VA | 22101