Guidelines for Review and Evaluation of Backcalculation Results

This document presents a new approach to determining layered elastic moduli from in situ load-deflection data, which was developed under the Federal Highway Administration's project for reviewing Long-Term Pavement Performance (LTPP) backcalculation data. This approach is called forwardcalculation, and it differs from backcalculation in that modulus estimates are calculated directly from the load and deflection data using closed-form formulae rather than through iteration. The closed-form forwardcalculation equations are used for the subgrade and the bound surface course, respectively, for both flexible and rigid pavement falling weight deflectometer (FWD) data. Intermediate layer moduli are estimated through commonly used modular ratios between adjacent layers. The audience for this document includes highway agency engineers, researchers, and consultants who are involved in pavement analysis, design, construction, and deflection data analysis.

• Record URL:
  https://www.fhwa.dot.gov/publications/research/infrastructure/pavements/ltpp/05152/05152.pdf
• 
• Record URL:
  https://rosap.ntl.bts.gov/view/dot/730
• Corporate Authors:

  Applied Research Associates, Incorporated

  ERES Consultants Division, 7184 Troy Hill Drive, Suite N
  Elkridge, MD  United States  21075

  Federal Highway Administration

  Office of Infrastructure Research and Development
  6300 Georgetown Pike
  McLean, VA  United States  22101
• Authors:
  • Stubstad, R N
  • Jiang, Y J
  • Lukanen, E O
• Publication Date: 2006-2

Language

• English

Media Info

• Media Type: Web
• Edition: Final Report
• Features: Figures; References; Tables;
• Pagination: 25p

Subject/Index Terms

• TRT Terms: Backcalculation; Deflection; Falling weight deflectometers; Flexible pavements; Guidelines; Modulus of elasticity; Rigid pavements; Subgrade (Pavements); Surface course (Pavements)
• Identifier Terms: Long-Term Pavement Performance Program
• Uncontrolled Terms: Closed form equations; Forwardcalculation; Layer moduli
• Subject Areas: Data and Information Technology; Design; Highways; Pavements; I22: Design of Pavements, Railways and Guideways; I23: Properties of Road Surfaces;

Filing Info

• Accession Number: 01025733
• Record Type: Publication
• Report/Paper Numbers: FHWA-RD-05-152
• Contract Numbers: DTFH61-02-D-00138
• Files: NTL, TRIS, USDOT
• Created Date: Jun 13 2006 4:26PM