1. Center of Excellence for Airport Technology, CEAT
Analysis of NAPTF Trafficking Dynamic Response Data For Pavement Deformation Behavior
Center of Excellence for Airport Technology, CEAT
Research Progress and FY07 Tasks – January 30, 2007
PI: Erol Tutumluer
RA: Phillip Donovan

2. Introduction
NAPTF designed to investigate NGA/pavement system interaction
Previous analysis found disturbing trends -- Wander caused downward deformation to be offset by upward deformation (shuffling of system elements)
May need improvements in our aggregate lab testing and modeling for permanent deformation
National Airport Pavement Test Facility (NAPTF) constructed to generate full-scale tests to investigate the performance of airport pavements subjected to complex gear loading configurations of new generation aircraft.
Previous analysis of NAPTF data by Hayhoe et al. (2004) found that the downward residual deformation from one pass seemed to be offset by upward residual deformation from another.
One consequence of this observation is that typical repeated load laboratory tests of permanent deformation in unbound pavement materials may not represent behavior under traffic

3. Research Objectives Detailed analysis of deformation trends Goals
(1) Investigate deformation trends based on
load magnitudes and loading sequences (stress history and application effects)
trafficking speeds (load duration effects)
traffic directions (shear stress reversals)
gear spacing and gear/wheel interaction
wander positions and wander sequence effects
(2) Validate rutting models for unbound base and subbase
Objective
This research project is aimed to utilize the NAPTF trafficking dynamic response database, as well as the response tests conducted in association with the trafficking tests, for a detailed analysis and better understanding of the CC1 and CC3 flexible pavement test section deformation trends (both recovered and unrecovered deformations).
Goals
(1) Investigate deformation trends with respect to the various combinations of applied
load magnitudes and loading sequences (application order and stress history effects);
trafficking speeds (load duration effects);
traffic directions (shear stress reversals);
gear spacing and gear/wheel interaction;
wander positions and wander sequences (order of 66 loadings); and
(2) Based on the previously proposed test procedure (Kim and Tutumluer, 2005), fully develop and validate models to evaluate and predict potential rutting in variable thickness unbound base/subbase courses due to realistic full scale aircraft gear loading.

4. Work Plan Status
Task I: Acquire NAPTF trafficking response data for the CC1 and CC3 test sections
Most data have been obtained
Some data not compiled yet
No data at all from LFC MDD sensors
CC3 trench data
Most sensors have limited amount of sensor records
Example: MFC 777 path sensor 1537, 16,000 events recorded only events have sensor records

5. Work Plan Status Too much data in other cases
LFS sensor records 400+ data points
Cannot analyze in Excel (only 256 columns)
Only last 200 data points required
Access to NAPTF database during FAA meeting in April would be extremely helpful
Data download and verification of sensors

6. Work Plan Status
Task II: Analyze NAPTF Trafficking Response Data for Individual Gear/Wheel Passes
Analysis of MFC 777 path data showing:
Effect of wander positions and wander
Effect of traffic direction

7. Task II: Progress Made In 2006
Just to give you an idea of what I’m talking about when I talk about sensors and sensor location and wander.

8. Task II: Progress Made In 2006
Line graph of Peak Responses

9. Task II: Progress Made In 2006
Scatter Graph of Peak Responses

10. Task II: Progress Made In 20064 4 3 3 2 2 -3 -3 -2 -2 -4 -1 -4 -1 1 1
Peak Response with wander
I was able to separate out the wander rows thanks to the master event to wander row file provided.
This is a 25pt moving average so the peaks are lower than what you saw on the last screen.

11. Task II: Progress Made In 2006
0 W-E
2 W-E
2 E-W
-3 E-W
-3 W-E
0 E-W
4 W-E
4 E-W
Directional Response of MDD Surface Sensor
For the directional response I was able to separate the rows by using the starting and ending position of the carriage.

12. Task II: Progress Made In 2006-2 4 -3
-4,4
-1 3 3 -3 2 1 -2 -1 -4 1
Time History Average of all available sensor records up to 16,000 events
Normalized means I averaged the first 1.5 seconds of data and subtracted that out from each data point
Then I averaged each time step data point for each wander pattern to produce the graph.
16,000 events

13. Task II: Progress Made In 2006
-3,-2,2 4 4 3 -1 -4 1 3 2 -2 -3 -4 -1
4000 events 1
Looking at the other surface sensor No we see something slightly different; dilative peaks of wander pattern 4. These did not show up in sensor 1544, or did they?

14. Task II: Progress Made In 20064
-3,-2,2 4 3
-1, -4 3 1 2 -2 -3 -4 -1 1
If we only look at the sensor records for sensor 1544 from the same set of data for sensor 1537 we see the exact same dilative peaks at the surface from wander row 4.

15. Work Plan Status Task II: continued
Analysis of other sensors progressing
MFC - 747
MFS – 747 (no 777 MDD data)
LFx – 777 and 747
Individual layer residual and rebound response

16. Work Plan Status
Task III: Analyze NAPTF trafficking response data for pavement loading until failure
To be evaluated after rutting analysis
Task IV: Identify and evaluate deformation trends in the CC1 and CC3 test sections
Progressing with Task II
Task V: Develop and Validate Realistic Granular Base/Subbase Deformation Models
To be evaluated after Tasks II-IV

17. Future Research

18. Future Research
Task II: Continue analysis of NAPTF trafficking response data for individual gear/wheel passes
Reduce data to actual sensor movement --Must subtract sensor readings from the exact same sensor reading of the anchors
Issue 1: matching the sensor records from the anchor to the other sensors
Issue 2: limited capabilities of Excel

19. NAPTF trafficking dynamic response
Base/Subbase
Contractive &
Dilative
Behavior

20. Future Research
Task IV: Identify and evaluate deformation trends in the CC1 and CC3 test sections
Based on Task II results, identify and quantify the trends
Task III: Analyze NAPTF trafficking response data for pavement loading until failure
Based on Task IV results, analyze data for failure

21. Future Research
Task V: Develop and Validate Realistic Granular Base/Subbase Deformation Models
Update Rutting model to include “normal” trafficking effects

22. Any Questions?