1. WELCOME TO THE
WEBINAR
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2. FWD Deflection Data Analysis and Backcalculation Tool: BcT 15 August 2017

3. FWD Deflection Data Analysis and Backcalculation Tool
Presenters:
Moderator:
John Donahue; MoDOT & Chairperson, AASHTOWare ME Design Task Force
Harold L. Von Quintus, P.E., ARA
Yanbin Zhang, ARA
Dinesh Ayyala, ARA
Presentation will be available for viewing on the ME-Design Resource website:
Judy: Introduce the presenters and announce where the presentation can be downloaded for future reference.

4. FWD Deflection Data Analysis and Backcalculation Tool
Phones are being muted.
Questions can be asked through the chat box
The presenters will answer all questions at the end of the demonstration.
Any question not answered because of time, will be answered after webinar and submitted to individual asking question.

5. Process for Enhancing the Software:
Suggested revisions are received from users and AASHTO members.
Pavement ME Design Task Force monitors on-going/completed NCHRP, FHWA, and pool fund projects applicable to the MEPDG.
Pavement ME Design Task Force members review and prioritize all potential suggested revisions and enhancements.
Judy: Overviews the activities of the task force for deciding what enhancements get done and turns presentations back to Chad.

6. Pavement ME Task Force Members
John Donahue, P.E.; Missouri DOT, Chairperson
Vicki Schofield, AASHTO Project Manager
Jay Goldbaum, P.E.; Colorado DOT
Marta Juhasz, P.E.; Alberta Transportation
Clark Morrison, P.E., North Carolina DOT
Robert Shugart, P.E.; Alabama DOT
Felix Doucet; TAC Liaison
Tom Yu, P.E.; FHWA Liaison
Shane Marshall, P.E.; Utah DOT, SCOJD Liaison
Jack Dartman, Montana DOT; T&AA Liaison

7. FWD Deflection Data Analysis and Backcalculation Tool
Before we get started:
Poll Questions #1 and #2
Chad: Brings up the poll question and summarizes the results.

8. FWD Deflection Data Analysis & Backcalculation Tool for Pavement ME
Presentation of BcT; an Overview:
Background Information
Products
Overview and Features of the Tool
Release Information
Demonstration of Tool
Questions and Answers

9. Background AASHTO Pavement ME Task Force Direction:
Develop a comprehensive tool to analyze and format deflection data, perform backcalculation and generate Pavement ME input files for rehabilitation design.
Backcalculation program is executed independently, but output is formatted according to Pavement ME input requirements.
Two versions of program:
English based units
SI based units

10. Background
Backcalculation software packages requested and considered for use; AASHTO required source code.
EVERCALC source code provided by Washington DOT; a special thank you to:
Jeff Uhlmeyer, Washington DOT
Nadarajah Sivaneswaran (Siva), FHWA
Linda Pierce, Nichols Consulting Engineers

11. Background Input and analysis considerations from other projects.
Backcalculation of LTPP Deflection Data; Report FHWA-HRT
FHWA Contact: Jane Jiang
Charaterization of Existing HMA Layer for ME Pavement Rehab. Design
DTFH61-14-C-00024
FHWA Contact: L. Wiser
AASHTO FWD Deflection Analysis & Backcalc. Tool for Use with Pavement ME Design
Backcalculation of Layer Parameters; Report FHWA-RD
FHWA Contact: C. Richter
MEPDG User Manual
Multiple other Projects Sponsored by State Agencies & FHWA.

12. FWD Deflection Data Analysis & Backcalculation Tool for Pavement ME
Presentation Overview:
Background Information
Products
Overview and Features of the Tool
Release Information
Demonstration of the Tool
Questions and Answers

13. Products
User information in support of Pavement ME input level 1 rehabilitation design:
Software or the analysis package; separate from the Pavement ME software.
Documents
User Manual; compliments the MEPDG Manual of Practice.
Extracted chapters from the EVERSERIES Manual related to backcalculation.

14. FWD Deflection Data Analysis & Backcalculation Tool for Pavement ME
Presentation Overview:
Background Information
Products
Overview and Features of the Tool
Release Information
Demonstration of the Tool
Questions and Answers

15. Overview and Features of Tool
Backcalcuation program is run independently but the output is formatted in accordance with Pavement ME input requirements.
Parts or utility tools in support of Pavement ME Design
Part 1—Preprocessing Deflection Data Tool for Backcalculation
Part 2—Backcalculation of layered elastic moduli
Part 3—Post processing backcalculation results for generating Pavement ME inputs.

16. Overview and Features of Tool
Input FWD Data
Segmentation Sensors
Preliminary Segmentation
Statistical Comparison
Final Segmentation
Structure Definition
Backcalculation
Physical Features
Export to ME Design

17. Overview and Features of Tool
Guides the user through the process, and provides a description of the feature and its function; similar to Pavement ME.

18. Overview and Features of Tool
BcT Help Manual

19. Part 1: Preprocessing Deflection Data
1. Import Raw FWD Data File
2. Cleanup and Filtering
3. Segmentation
4. Pavement Structure Definition
Generate input files using pre-processed data
File format is compatible for use with EVERCALC®
Generation of Input Files for EVERCALC

20. Part 1: Preprocessing Deflection Data
1. Import FWD Data File
Convert file into one standard format for backcalculation.
Five FWD file format converters:
KUAB – .FWD
JILS – .DAT
Dynatest – V20 (*.FWD)
Dynatest - F20 (*.F20)
Dynatest – V25 (*.F25)

21. Part 1: Preprocessing Deflection Data
Read FWD data file
Data organized and displayed through three tables:
Upper table contains a list of stations and attributes (temperatures, elevation, etc.).
Middle table shows the sensor configuration.
Lower table shows deflection data at all drops for the station selected in upper table.
1. Import FWD Data File

22. Part 1: Preprocessing Deflection Data
Program classifies deflection basins into four types:
Typical
Type 2 – Significant decrease in deflection between two adjacent sensors
Type 1 – Deflections at some sensors greater than D0
Type 3 – Non- decreasing deflection at adjacent sensors
2. Data Cleanup and Filtering

23. Part 1: Preprocessing Deflection Data
Typical
Type 1
Normalized Deflection Basin Types
Type 2
Type 3
Source: Von Quintus and Simpson (1998)

24. Part 1: Preprocessing Deflection Data
Filter for deflection charts:
Drop Load
Test Type
Basin Characterization
Lane/Direction
Sensors; Defl. Charts
3. Segmentation

25. Part 1: Preprocessing Deflection Data
Preliminary Segmentation:
Automatic process based on cumulative area method.
Used in MODULUS
Statistical comparison for segments:
F-test: Test for variance
t-test: test for means 1 2 3 4 1 2 3 4 5 1 2 3 4 5
3. Segmentation

26. Part 1: Preprocessing Deflection Data
Cursor used to manually define the location of each segment.
Final segments selected by user. 1 2 3 4
3. Segmentation

27. Part 1: Preprocessing Deflection Data
Evercalc Inputs:
Layer #
Layer Type
Thickness
Poisson’s Ratio
Min. E
Max. E
Seed E 1 2 3 4
4. Structure Definition

28. Part 2: Backcalculation
Input Files Generated from preprocessed data
Backcalculation process is EVERCALC®
Output File
Pavement layer moduli and other parameters
Separate output file for each individual segment.
Results – backcalculated moduli for each pavement layer and RMSE displayed as charts on the interface.
No user activity – process is completely automated.

29. Part 2: Backcalculation
Compensating Layer Effects
Layer Elastic Modulus
Sensors used in backcalculation.
Root Mean Squared Error
Review Backcalculation Results

30. Part 2: Backcalculation
Based on RMSE and backcalculated modulus value
Criterion
Acceptable
Atypical
Unacceptable
RMSE
≤3.0
3 to 5
>5.0
Modulus
Within Acceptable range limits
Outside acceptable but within atypical limits
Outside Atypical range limits
Acceptable
Atypical
Error

31. Part 2: Backcalculation
Compensating Layer Effects
User makes decision on whether structure needs to be changed because of compensating layer effects
Use graph to check for the E upper or lower boundary limits.
Compensating Layer Effects

32. Part 2: Backcalculation
Load Transfer Efficiency
Two sensors used for LTE.
LTE for HMA and PCC: defined by LTPP.
Void Analysis: defined by 1993 AASHTO
Void Analysis
Physical Features

33. Part 2: Backcalculation; Physical Features
LTE for HMA & PCC: defined by LTPP.
Void Analysis: defined by 1993 AASHTO

34. Part 3: Post-Processing of Backcalculation Results
Input Files
Intermediate text files from backcalculation
Post-processing & summarization of results
Output File
DGPX file as input to Pavement ME for rehab design
Summarize individual drops and segment average results – displayed on the interface in Export to ME Design tab.
Summary includes analysis statistics such as RMSE and quality of convergence.
Post-processor generates an output DGPX (.dgpx) file.

35. Part 3: Post-Processing of Backcalculation Results
Export to ME Design:
Layer description tied back to default materials in Pavement ME.
Average E for each layer.
Standard deviation and coefficient of variation included in summary.
LTE, temperature, and frequency included as outputs.

36. FWD Deflection Data Analysis & Backcalculation Tool for Pavement ME
Presentation Overview:
Background Information
Products
Overview and Features of the Tool
Release Information
Demonstration of the Tool
Questions and Answers

37. Release Information
Released July 2017 with Pavement ME Design software, along with the User Manual.
Authorization code tied to license for Pavement ME Design.

38. BcT Software
Software and documentation can be downloaded from AASHTWare web site

39. BcT Software

40. BcT Software

41. BcT User Manual

42. FWD Deflection Data Analysis & Backcalculation Tool for Pavement ME
Poll Question #3
Chad: Brings up the poll question and summarizes the results.

43. FWD Deflection Data Analysis & Backcalculation Tool for Pavement ME
Demonstration of BcT for Rehabilitation Design

44. FWD Deflection Data Analysis & Backcalculation Tool for Pavement ME
Poll Questions #4, #5, and #6
Chad: Brings up the poll question and summarizes the results.

45. Question and answer Session
AASHTOWare: Pavement ME Design
FY17 Enhancement
Question and answer Session
We welcome comments & suggestions for future webinars; Send an to
Harold – moderates the question and answer period.

46. FWD Deflection Data Analysis & Backcalculation Tool for Pavement ME Design
Remember the Pavement ME Design Users Group Meeting scheduled for October 11 and 12, 2017 in Denver, CO.

47. Thank you for Attending the Webinar!
AASHTOWare Pavement ME-Design Contacts:
Vicki Schofield, AASHTO
Phone: (202)
John Donahue, MoDOT
ME Design Resource Website
Pavement ME Design Users Group Contact:
Christopher Wagner, FHWA
Phone: (404)
Help Desk, Customer Support:
ARA Staff:
Deepak Raghunathan, ARA Inc.
Phone: (217)
Biplab Bhattacharya, P.E.
Other ARA Staff:
Chad Becker
Harold Von Quintus, P.E.
Michael I. Darter, P.E.
Harold: Identify the AASHTOWare contacts and thanks everyone for participating.
Judy: Thanks everyone for participating in the webinar.