DEFLECTOMETER FOR MEASURING CONCRETE PAVEMENT DEFLECTIONS UNDER MOVING LOADS

THE DEFLECTOMETER WAS DESIGNED TO MEASURE CONCRETE PAVEMENT DEFLECTIONS AT ANY DESIRED POINT UNDER MOVING LOADS. THE INSTRUMENT DEVELOPED CONSISTS ESSENTIALLY OF A RATIO ARM OF 25 TO 1 OBTAINED BY A TRAIN OF GEARS AND A KYMOGRAPH DRUM ON WHICH DEFLECTIONS, SPEED-SWITCH INDICATORS AND A TIME-GRAPH ARE RECORDED SIMULTANEOUSLY. DEFLECTIONS OF A SLAB AT THE POINT TO BE MEASURED MAY BE DETERMINED FOR ANY POSITION OF THE MOVING AXLE LOAD BY CALCULATING DISTANCES FROM THE AVERAGE-SPEED OF THE MOVING LOAD. TIMING IS CONTROLLED BY A STANDARD TUNING FORK OF 100 VIBRATIONS PER SECOND. WITH AN OPTIMUM SPEED OF THE KYMOGRAPH DRUM, IT IS POSSIBLE TO DETERMINE THE TIME WITHIN PLUS OR MINUS 0.001 SEC. PRELIMINARY TESTS BY STATIC DISPLACEMENTS SHOW THAT IT IS POSSIBLE TO MEASURE DISPLACEMENTS OF THE MAGNIFICATION ARM WITHIN PLUS OR MINUS 0.001 IN. ACTUAL DISPLACEMENTS ARE MEASURED WITH AN "88" AMES DIAL AND MAGNIFIED DISPLACEMENTS ON THE KYMOGRAPH CHART ARE MEASURED WITH A PAIR OF MICROCALIPERS. /AUTHOR/

• Record URL:
  • https://onlinepubs.trb.org/Onlinepubs/hrbproceedings/23/23-029.pdf
• Supplemental Notes:
  • Vol 23, pp 317-324, 9 PHOT. Distribution, posting, or copying of this PDF is strictly prohibited without written permission of the Transportation Research Board of the National Academy of Sciences. Unless otherwise indicated, all materials in this PDF are copyrighted by the National Academy of Sciences. Copyright © National Academy of Sciences. All rights reserved.
• Authors:
  • Couch, R W
• Publication Date: 1944

Media Info

• Media Type: Digital/other
• Monograph Title: Proceedings of the Twenty-Third Annual Meeting of the Highway Research Board Held at Edgewater Beach Hotel, Chicago, Illinois November 27-30, 1943
• Serial:
  • Highway Research Board Proceedings
  • Volume: 23
  • Publisher: Highway Research Board

Subject/Index Terms

• TRT Terms: Concrete pavements; Deflection; Deflectometers; Loads; Motion; Moving industry
• Subject Areas: Freight Transportation; Highways; Pavements;

Filing Info

• Accession Number: 00207301
• Record Type: Publication
• Files: TRIS, TRB
• Created Date: Jul 18 1971 12:00AM