Application of Surface Strain Gages at the FAA's National Airport Pavement Test Facility

Since 1999, over a thousand embedded concrete strain gages have been used at the FAA's NAPTF. However, two issues have to be considered. First, extrapolation of the data, rather than direct measurement, has to be used to obtain the critical strain at slab surface. Second, each gage costs more than 500 dollars necessitating a reduction in the amount of strain gages to satisfy budgetary requirements. To alleviate these concerns, surface strain gages have been used since 2004. The cost of each gage is typically less than ten dollars, and its reliability is similar to the embedded gages if they are used appropriately. Seven surface gages were installed at a transverse joint and one at a longitudinal joint of a 17" thick slab. Two-step static gear loads and slow rolling loads were used to get strain histories. Two, four and six wheels were used for both static and slow rolling tests. The test data verifies the findings at NAPTF in 2000: The gear load dominates both top-down and bottom-up cracks at transverse joints, and it only dominates the top-down cracks while the wheel load dominates the bottom-up cracks at longitudinal joints. Comparisons between the recorded strains under static and slow rolling load show that the magnitude of strain history under a slow rolling load matches the measured static strain very well if the load location is properly selected. The measured and calculated strains based on a thin plate model at the longitudinal joint under a slow rolling load match well. However, the measured and calculated strains at the transverse joint only match well for the strain gage locations away from the load. They are poorly matched for the gage near the load. The discrepancy indicates that the thin plate model assumption might not be suitable in predicting surface strain near the load.

• Record URL:
  • http://www.airporttech.tc.faa.gov/Airport-R-D/Conference-and-Workshop/Airport-RD-Conference-Detail/dt/Detail/ItemID/364/Application-of-Surface-Strain-Gages-at-the-FAA's-National-Airport-Pavement-Test-Facility
• Record URL:
  • http://www.airtech.tc.faa.gov/naptf/att07/2007/Papers/P07078%20Guo%26Pecht.pdf
• 
• Corporate Authors:

  Federal Aviation Administration

  800 Independence Avenue, SW
  Washington, DC  United States  20591
• Authors:
  • Guo, Edward
  • Pecht, Frank
• Conference:
  • 2007 Worldwide Airport Technology Transfer Conference
  • Location: Atlantic City New Jersey, United States
  • Date: 2007-4-16 to 2007-4-18
• Publication Date: 2007

Language

• English

Media Info

• Media Type: Digital/other
• Features: Figures; Photos; References;
• Pagination: 17p
• Monograph Title: 2007 FAA Worldwide Airport Technology Transfer Conference: New Directions in Airport Technology

Subject/Index Terms

• TRT Terms: Airport runways; Landing gear; Longitudinal joints; Strain gages; Strain measurement; Transverse joints; Wheel loads
• Identifier Terms: National Airport Pavement Test Facility
• Subject Areas: Aviation; Pavements; Terminals and Facilities;

Filing Info

• Accession Number: 01615688
• Record Type: Publication
• Files: TRIS, ATRI, USDOT
• Created Date: Oct 31 2016 4:58PM