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Title: DETERMINATION OF DEPTH TO BEDROCK FROM FALLING WEIGHT DEFLECTOMETER TEST DATA
Accession Number: 00715544
Record Type: Component
Availability: Find a library where document is available Abstract: Depth to bedrock can have a significant effect on the moduli of the surface layer, base, and subgrade backcalculated from Falling Weight Deflectometer (FWD) tests when the calculations are performed using a static analysis. On the other hand, when the backcalculation is based on dynamic analysis of the FWD test, the resulting moduli are quite insensitive to the depth to bedrock if this depth is larger than about 3 m (10 ft). When only the peak deflections at the seven receivers are recorded, there is little that can be done analytically to account for the depth to bedrock. However, when the time histories of the motions at the various receivers are stored, one can estimate both the depth to bedrock and the modulus of the subgrade rather easily from the time histories. These estimations are most correctly applied to time histories of 0.12 sec or longer rather than the 0.06 sec conventionally recorded. In this article, the results of a number of parametric studies simulating the FWD test on three flexible pavements and one rigid pavement are presented. From these results, approximate expressions were developed for (a) estimating the depth to bedrock, (b) computing the natural period of vibration of the pavement system, which is nearly equal to that of the subgrade layer, and (c) estimating the wave propagation velocity and modulus.
Supplemental Notes: This paper appears in Transportation Research Record No. 1504, Modeling and Model Verification; Testing Pavement Layers and Materials; and Low-Cost Drainage Structures. 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
Monograph Title: Monograph Accession #: 01399829
Language: English
Authors: Roesset, Jose MStokoe II, Kenneth HSeng, Chia-RayPagination: p. 68-78
Publication Date: 1995
Serial: ISBN: 0309061725
Features: Figures
(12)
; References
(5)
; Tables
(3)
TRT Terms: Uncontrolled Terms: Subject Areas: Design; Highways; Pavements; I22: Design of Pavements, Railways and Guideways; I23: Properties of Road Surfaces
Files: TRIS, TRB
Created Date: Jan 2 1996 12:00AM
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