Dynamic Analysis Of Falling Weight Deflectometer Data
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Dynamic Analysis Of Falling Weight Deflectometer Data
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Author : Boutros E. Sebaaly
language : en
Publisher:
Release Date : 1986
Dynamic Analysis Of Falling Weight Deflectometer Data written by Boutros E. Sebaaly and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 1986 with Pavements categories.
Development Of Dynamic Analysis Techniques For Falling Weight Deflectometer Data
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Author : Allen H. Magnuson
language : en
Publisher:
Release Date : 1997
Development Of Dynamic Analysis Techniques For Falling Weight Deflectometer Data written by Allen H. Magnuson and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 1997 with Pavements categories.
Dynamic Analysis Of Falling Weight Deflectometer Data
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Author : Allen H. Magnuson
language : en
Publisher:
Release Date : 1988
Dynamic Analysis Of Falling Weight Deflectometer Data written by Allen H. Magnuson and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 1988 with Pavements categories.
Falling-Weight Deflectometer data from three in-service pavement sections has been used to analyze dynamic response characteristics. The Analyzed data will be used later in the project along with computer predictions of pavement response to back-calculate engineering properties of pavements. The pavements had thicknesses of 1.5 in., 9 in., and 12 in., and two load levels were tested. The full pulse data is presented for the dropweight force and all seven surface displacement sensors. The analysis was performed in the frequency domain using frequency response functions computed from the pulse data. The frequency response functions were computed by dividing the Fast Fourier Transform (FFT) of the displacements by the FFI of the force. Magnitude and phase angles of the frequency response functions are presented. An undesirable oscillation was present in the frequency response functions. This was attributed to a discontinuity in the displacement pulses resulting from zero-packing in the FFT Program. The pulses have a non-zero "tail" value at the end of the 60 msec sample period which causes the discontinuity. The pulse "tail" may be due to drift, permanent deformation of the pavement, or premature truncation before the transient response had died out. A linear correction to the pulses that eliminated the discontinuity was applied to one test case. This eliminated the undesirable oscillation, giving the responses a more regular behavior similar to predicted theoretical responses. This correction should facilitate comparison studies of computed versus measured FWD responses.
Computer Analysis Of Falling Weight Deflectometer Data
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Author : Allen H. Magnuson
language : en
Publisher:
Release Date : 1988
Computer Analysis Of Falling Weight Deflectometer Data written by Allen H. Magnuson and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 1988 with Pavements categories.
A computer algorithm SCALPOT, consisting of a set of programs and linked files, has been developed that computes responses for physical and geometrical conditions simulating the Dynatest Falling-Weight Deflectometer. Related work on dynamic analysis of layered elastic and viscoelastic media is reviewed. The pavement dynamics problem as measured by the FWD is shown to be a near-field or intermediate-field problem requiring different integration techniques than far-feld problems arising in seismic work. Integration of the formal solution is shown to be best treated by direct numerical integration using a newly developed method of estimating truncation error.
Enhanced Analysis Of Falling Weight Deflectometer Data For Use With Mechanistic Empirical Flexible Pavement Design And Analysis And Recommendations For Improvements To Falling Weight Deflectometers
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Author : Karim Chatti
language : en
Publisher:
Release Date : 2017
Enhanced Analysis Of Falling Weight Deflectometer Data For Use With Mechanistic Empirical Flexible Pavement Design And Analysis And Recommendations For Improvements To Falling Weight Deflectometers written by Karim Chatti and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2017 with Pavements categories.
This report describes the efforts undertaken to review the status of falling weight deflectometer (FWD) equipment, data collection, analysis, and interpretation, including dynamic backcalculation, as they relate to the models and procedures incorporated in the Mechanistic-Empirical Pavement Design Guide. The work conducted in this project resulted in the following: Development of a backcalculation scheme (BACKLAVA) in the time domain using a quasi-static model (LAVA) as its forward solution and genetic algorithm (GA) as its search engine. BACKLAVA is a backcalculation algorithm for a constant asphalt concrete (AC) layer temperature. Development of a backcalculation scheme (BACKLAVAP) in the time domain using a quasi-static model (LAVAP) as its forward solution and GA as its search engine. BACKLAVAP is a backcalculation algorithm for a temperature profile in an AC layer. Development of a backcalculation scheme (BACKLAVAN) in the time domain using a quasi-static model (LAVAN) as its forward solution and GA as its search engine. BACKLAVAN is a backcalculation algorithm for a viscoelastic AC layer and a nonlinear base layer. Development of a backcalculation scheme (DYNABACK-VE) in the time domain using a time-domain viscoelastic dynamic model (ViscoWave-II) as its forward solution and a hybrid approach (GA and Levenberg-Marquardt algorithm) as its search engine. DYNABACK-VE is a backcalculation algorithm for a viscoelastic AC layer with temperature profile and linear unbound layers. Short list of recommendations for FWD equipment enhancements. The tools developed in this project are standalone applications that could be used on most computers.
Nondestructive Testing Of Pavements And Backcalculation Of Moduli
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Author : Shiraz D. Tayabji
language : en
Publisher: ASTM International
Release Date : 2000
Nondestructive Testing Of Pavements And Backcalculation Of Moduli written by Shiraz D. Tayabji and has been published by ASTM International this book supported file pdf, txt, epub, kindle and other format this book has been release on 2000 with Materials categories.
As with the previous two symposia, the 32 papers from the June/July, 1999, Seattle symposium present advances in the nondestructive testing of pavements using conventional falling weight deflectometer techniques and other promising techniques such as ground penetrating radar, rolling weight deflecto
Use Of Falling Weight Deflectometer Multi Load Data For Pavement Strength Estimation
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Author : Y. Richard Kim
language : en
Publisher:
Release Date : 2002
Use Of Falling Weight Deflectometer Multi Load Data For Pavement Strength Estimation written by Y. Richard Kim and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2002 with Pavements categories.
The objective of this study is to develop a mechanistic-empirical method for assessing pavement layer conditions and estimating the remaining life of flexible pavements using multi-load level Falling Weight Deflectometer (FWD) deflections. A dynamic finite element program, incorporating a stress-dependent soil model, was developed to generate the synthetic deflection database. Based on this synthetic database, the relationships between surface deflections and critical pavement responses, such as stresses and strains in each individual layer, have been established. A condition assessment procedure for asphalt pavements that uses multi-load level FWD deflections has been developed using these relationships. The verification study was conducted using field data.
Case Studies Using Falling Weight Deflectometer Data With Mechanistic Empirical Design And Analysis
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Author : Kurt D. Smith
language : en
Publisher:
Release Date : 2012
Case Studies Using Falling Weight Deflectometer Data With Mechanistic Empirical Design And Analysis written by Kurt D. Smith and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2012 with Falling weight deflectometer categories.
The need to accurately characterize the structural condition of existing pavements has increased with the recent development, release, and ongoing implementation of the Mechanistic-Empirical Pavement Design Guide (MEPDG), developed under National Cooperative Highway Research Program Project No. 1-37A. A number of different material inputs are required in the procedure, and it is important that these be adequately characterized and defined so that competent structural designs can be developed. The analysis of deflection data collected with a falling weight deflectometer (FWD) provides a quick and reliable way of characterizing many of the parameters of the existing pavement layers. This paper summarizes how deflection data are incorporated into the MEPDG and describes two case studies, one with a flexible pavement and one with a rigid pavement. Significant findings and recommendations from the evaluated flexible pavement case study include the following: surface-down cracking is critical in the design of the hot mix asphalt (HMA) overlay, correction factors should be used for adjusting backcalculated layer moduli to laboratory determined values, and an FWD testing frequency of 30 Hz should be used for estimating the existing HMA modulus. For rigid pavements, the case study found that the thinnest overlay produced from the MEPDG was a bonded Portland cement concrete (PCC) overlay, whereas the HMA overlay was unreasonably thick. Within the design procedure, the manually entered k-value is used for unbonded and bonded jointed plain concrete pavements but does not appear to be used by the program in the HMA overlay design. The backcalculated dynamic (or static) elastic modulus should be used for the PCC layer, and the dynamic k-value should be used for the supporting layers. The backcalculated k-value representing the composite stiffness of all layers beneath the slab does not appear to have a significant influence on the design thickness for the pavement structure analyzed.
The Falling Weight Deflectometer And Spectral Analysis Of Surface Waves Test For Characterizing Pavement Moduli
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Author : Kenneth H. Stokoe
language : en
Publisher:
Release Date : 1991
The Falling Weight Deflectometer And Spectral Analysis Of Surface Waves Test For Characterizing Pavement Moduli written by Kenneth H. Stokoe and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 1991 with Pavements categories.
This report details the results of tests on newly constructed flexible pavement using a Dynatest 9000 Falling Weight Deflectometer and the Spectral Analysis of Surface Waves test. Additional types of field and laboratory tests were also undertaken and are reported in this study. Taken together, the data and analyses represent a detailed case study of the two non-destructive test methods. When dynamic effects and the demonstrated non-linear behavior of the soil are accounted for, Spectral Analysis of Surface Waves and the Falling Weight Deflectometer provide similar subgrade moduli.
Dynamic Backcalculation And Overlay Design Based On Fwd Data
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Author : H. Yokota
language : en
Publisher:
Release Date : 2000
Dynamic Backcalculation And Overlay Design Based On Fwd Data written by H. Yokota and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2000 with Backcalculation categories.
A study on dynamic backcalculation and overlay design based on falling weight deflectometer (FWD) data is presented. Dynamic slab-ground theory (DSGT) was used for dynamic backcalculation of a pavement structure. A computer program based on DSGT generated theoretical dynamic deflections of the pavement. For the backcalculation of equivalent full-depth asphalt concrete (AC) thickness and subgrade modulus, these deflections were matched with FWD deflections from major roads in Miyazaki Prefecture, Japan. Temperature influence on Young's modulus of AC was also considered. Results were then compared with those from DSGT's static analysis version (SSGT) and also from a Japanese representative method, NIPPO, which is a static elastic multilayer method. Characteristics of dynamic backcalculation analysis are discussed. The range of pavement variables showing necessity for dynamic analysis was also considered by comparison of theoretical deflections using DSGT and SSGT. Furthermore, overlay thickness design using Kentucky Transportation Center's procedure was carried out.