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    <title>Transport Research International Documentation (TRID)</title>
    <link>https://trid.trb.org/</link>
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    <language>en-us</language>
    <copyright>Copyright © 2026. National Academy of Sciences. All rights reserved.</copyright>
    <docs>http://blogs.law.harvard.edu/tech/rss</docs>
    <managingEditor>tris-trb@nas.edu (Bill McLeod)</managingEditor>
    <webMaster>tris-trb@nas.edu (Bill McLeod)</webMaster>
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      <title>Transport Research International Documentation (TRID)</title>
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      <link>https://trid.trb.org/</link>
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    <item>
      <title>COMPUTER AIDED FLEXIBLE PAVEMENT ANALYSIS</title>
      <link>https://trid.trb.org/View/194656</link>
      <description><![CDATA[The Benkelman beam is widely accepted as a means of assessing the relative strengths of flexible pavements.  In certain countries considerable data have been collected which have enabled transient deflection to yield not only relative strengths, but also an indication of residual life and, where necessary, overlay thickness requirements.  In the majority of countries the data necessary for such an extension, and therefore the full use of deflection techniques, do not exist.  In an effort to assist in these areas, a technique of computer modelling of pavements has been devised.  With this it has been possible to predict the influence of temperature on the deflections of bituminous pavements, the correlation of the Benkelman beam deflection with that of the deflectograph and the effect of overlaying on deflection.  The results of the computations have been compared favourably against field measurements and in the case of overlays two full scale experiments were carried out yielding close correlation.  It is therefore suggested that these techniques should be used to replace the widespread abuse of empirically derived charts in areas for which they were not designed.  (Author/TRRL)]]></description>
      <pubDate>Sun, 30 Oct 1983 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/194656</guid>
    </item>
    <item>
      <title>PAVEMENT PERFORMANCE STUDY FOR OVERLAY DECISION</title>
      <link>https://trid.trb.org/View/194657</link>
      <description><![CDATA[In this paper, the dynaflect deflection measurement is used in a model to evaluate existing pavement performance and characteristics, furthermore to predict the behavior of the pavement system with the overlay.  Deflection data are used in several nomographs generated from elastic analysis to evaluate pavement properties.  These in turn will help determine the stresses under the load prior to and after the overlay.  The model uses statistical techniques for deflection analysis to generate pavement properties as related to bearing capacity.  (Author/TRRL)]]></description>
      <pubDate>Tue, 30 Aug 1983 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/194657</guid>
    </item>
    <item>
      <title>REBOUNDS ON UNPAVED ROADS USING THE BENKELMAN BEAM</title>
      <link>https://trid.trb.org/View/194658</link>
      <description><![CDATA[The Benkelman beam, designed to measure the subsequent rebounds of an asphaltic concrete surfaced road after a standard wheel load has passed, was utilized to monitor thickness design and construction uniformity on granular surfaced forest roads in eastern Canada.  Preliminary testing conducted on a low-quality forest access road indicated that the beam could be used without modification. The spring/fall rebound ratio was found to be greater than that generally found for surfaced highways.  The effect of precipitation on the measured rebound could be discerned almost immediately.  Further testing on a private forest haul road confirmed these findings.  Measurements of rebound on a full-scale test road were conducted to determine the beam's applicability to design of granular surface thickness on forest roads.  Correlation of measured rebounds with road base thickness was difficult to achieve. Further testing indicated measured rebounds tended to become smaller as road usage increased.  (Author/TRRL)]]></description>
      <pubDate>Tue, 30 Aug 1983 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/194658</guid>
    </item>
    <item>
      <title>DYNAMIC DEFLECTIONS OF PAVEMENT: MEASUREMENTS, INTERPRETATIONS AND APPLICATIONS</title>
      <link>https://trid.trb.org/View/194659</link>
      <description><![CDATA[Recent emphasis by highway agencies on pavement management system makes it almost imperative to monitor the in-service behavior of pavements periodically and systematically. Pavement deflection measurements are increasingly being used as a part of this state-wide monitoring system.  Equipment like dynaflect, road rater and wes vibrator are used for dynamic deflection measurements, among which dynaflect is the most used one in the United States.  Five performance parameters - dmd, sci, bci, sp and w5 are associated with the dynaflect measurements.  The physical significance of each of these parameters is described.  A structural diagnosis chart utilizing all the parameters is presented to estimate the structural characteristics of the measured pavement system.  A nomograph is presented to check the adequacy of sample size of pavement deflections at 95 percent confidence level.  Significance of temperature adjustment factor and seasonal adjustment factor is enumerated.  Design charts to determine overlay thickness of flexible pavements based on dmd and sci crtieria are presented.  Application of dynaflect deflections in the evaluation of hot and cold recycled pavements is also discussed.  (Author/TRRL)]]></description>
      <pubDate>Tue, 30 Aug 1983 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/194659</guid>
    </item>
    <item>
      <title>THE SPANISH STANDARD FOR STRENGTHENING OF ROAD PAVEMENTS</title>
      <link>https://trid.trb.org/View/194660</link>
      <description><![CDATA[Pavement strengthening in Spain is regulated by a standard published in 1979.  The principal factors determining the type of strengthening and the thickness of the overlay are the expected traffic during the design life and the characteristics of the existing pavement.  Where flexible pavements are concerned, the basic factor for determining the bearing capacity of the pavement is the standardised characteristic deflection of each uniform section, adjusted by factors that take into account the measuring equipment, the pavement temperature and the subgrade moisture.  Three types of overlay are established, according to the base type: granular, bituminous or hydraulic binder. For each type a catalogue is provided giving the layer thicknesses as a function of the traffic and deflection classes concerned. This paper describes the operational system used to evaluate the need for strengthening, the bearing capacity of the existing pavement and the thickness design of the overlay.  (Author/TRRL)]]></description>
      <pubDate>Tue, 30 Aug 1983 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/194660</guid>
    </item>
    <item>
      <title>ROAD RATER OVERLAY THICKNESS DESIGN FOR MODIFIED FLEXIBLE PAVEMENTS</title>
      <link>https://trid.trb.org/View/194661</link>
      <description><![CDATA[The maintenance and rehabilitation of a nation's highways has become one of the most important areas of concern facing highway engineers today.  Many highway agencies are now developing rational methods of pavement analysis and overlay design procedures.  This report discusses an evaluation of the Pennsylvania Department of Transportation road rater deflection overlay design procedure.  The report is based upon field data which was collected at the Pennsylvania transportation research facility.  The data included pavement roughness, cracking, rut depth, static deflections and dynamic road rater deflections. Relationships of surface deflections and present serviceability index were developed. Pavements were constructed with bituminous concrete, aggregate cement and aggregate-lime-pozzolan base materials. Overlay thicknesses required for various terminal serviceability indexes were determined using the BISAR elastic layer computer program.  (Author/TRRL)]]></description>
      <pubDate>Tue, 30 Aug 1983 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/194661</guid>
    </item>
    <item>
      <title>OVERLAY DESIGN OF FLEXIBLE PAVEMENTS USING DYNAFLECT</title>
      <link>https://trid.trb.org/View/194662</link>
      <description><![CDATA[This paper presents a fully computerized rational method for the design of flexible overlays of flexible pavements using dynaflect.  The overlay thickness is determined based on a fatigue distress function which was developed from analyzing the AASHO test road data, and relates horizontal tensile strain in the asphalt layer to the number of equivalent 18 kip (80 kn) axle loads to failure.  The existing pavement is evaluated using non-destructive dynamic deflection measurements and a visual survey which includes general observations regarding drainage, the existence of rutting, and the presence and type of cracking.  The deflection data are analyzed using linear elastic theory in which the existing pavement is represented by a 4-layer model consisting of a pavement layer, base and subbase layers, and a subgrade layer.  The in-situ layer stiffnesses are determined by matching measured deflections with those computed from layer theory. The design procedure recognizes that asphalt modulus is temperature dependent and the in-situ asphalt modulus is compensated for temperature and this adjusted modulus is used in design computation.  The base and subgrade materials are corrected for stress effects when the state of stress is changed as a result of adding an overlay.  The procedure also incorporates an environmental factor.  (Author/TRRL)]]></description>
      <pubDate>Tue, 30 Aug 1983 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/194662</guid>
    </item>
    <item>
      <title>DEFLECTION BASIN SHAPE AS BEARING CAPACITY INDICATOR FOR PAVEMENT STRENGTHENING PURPOSES</title>
      <link>https://trid.trb.org/View/194663</link>
      <description><![CDATA[In the past ten years, the strengthening of Portuguese road pavements, in general of the flexible type, has been designed by a method developed in Portugal.  According to this method the thickness of the strengthening overlay is established by limiting to safe values the stresses that expected traffic will induce in the strengthening layer as well as in the existing pavement.  Calculations are based on a knowledge of the structural properties of the overlay material (asphalt concrete as a rule), as well as of the old pavement and its foundation.  These properties are evaluated through an analysis of the deflection basin produced by the 9-ton axle of a special test truck.  The basic principles and concepts of the method are described in this paper, together with measurement strategies, and data processing procedures.  Applications of the method in recent years are also mentioned.  (Author/TRRL)]]></description>
      <pubDate>Tue, 30 Aug 1983 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/194663</guid>
    </item>
    <item>
      <title>OVERLAY DESIGN OF RIGID PAVEMENTS USING DYNAFLECT</title>
      <link>https://trid.trb.org/View/194664</link>
      <description><![CDATA[The review of currently available overlay design methods indicates that these may be grouped in three categories: those based on a visual condition rating, those using ndt deflections and relationships between allowable deflection and overlay needs, and semi-rational procedures using stress analysis.  The more promising of these procedures were subjected to detailed analysis and compared using data from a variety of projects.  This paper presents the formulation of a method that attempts to overcome the difficulties and limitations of current methods.  The proposed method utilizes both ndt and visual condition evaluation as well as limited destructive and laboratory testing to evaluate existing pavement condition.  A coupled fem-multilayer elastic subgrade is used in stress analysis, and the amount of overlay is determined based on limiting formation of load-induced fatigue cracking.  (Author/TRRL)]]></description>
      <pubDate>Tue, 30 Aug 1983 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/194664</guid>
    </item>
    <item>
      <title>NORWEGIAN PRACTICES FOR AXLE LOAD RESTRICTIONS IN SPRING THAW</title>
      <link>https://trid.trb.org/View/194665</link>
      <description><![CDATA[Due to better knowledge of the bearing capacity of public roads a new axle load policy was introduced in Norway in 1979: 10 tons with restrictions during the thaw period. Registrations of the bearing capacity also indicated that about 3/4 of the national roads could be overloaded during spring time if no restrictions of axle loads were carried out.  The new policy and the wish to reduce maintenance costs due to overloading made it necessary to draw up guidelines for applying restrictions during the thaw period. These guidelines indicate where and when restrictions should be used, systems for exemptions, weight control and information/announcements. Means and ways of determining the period and scope of restrictions are given.  Restrictions should commence when the thaw is not more than 10-20 cms below the road surface. The lifting date can be stipulated by measuring the thaw depth.  The amount of reductions in axle load is determined by deflection measurements on reference sections.  As an average this leads to a reduction of 2 tons on the roads in question.  (Author/TRRL)]]></description>
      <pubDate>Tue, 30 Aug 1983 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/194665</guid>
    </item>
    <item>
      <title>RESIDUAL LIFE DETERMINATION OF FLEXIBLE AIRFIELD PAVEMENT SYSTEMS</title>
      <link>https://trid.trb.org/View/194666</link>
      <description><![CDATA[Conventional airfield pavement evaluation techniques do not give an indication of the balance functional life of the pavement.  An evaluation method using a dynamic loading system to assess the residual life of flexible airfield pavement systems has been developed by the International Airports Authority of India (IAAI).  The testing is non-destructive in nature and requires minimal time on a busy runway.  The method proposes determination of the in-situ elastic properties of the component layers of the pavement which are then modified to account for the effect of the various environmental cycles and used as inputs in A computer-aided analysis of the pavement system to determine its residual life from aircraft dynamic response and pavement fatigue considerations.  (Author/TRRL)]]></description>
      <pubDate>Tue, 30 Aug 1983 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/194666</guid>
    </item>
    <item>
      <title>USER'S EXPERIENCE WITH THE SOUTH AFRICAN HEAVY VEHICLE SIMULATORS</title>
      <link>https://trid.trb.org/View/194626</link>
      <description><![CDATA[The Heavy Vehicle Simulator, HVS, is a mobile testing machine for subjecting roads and airfields to accelerated trafficking.  Four HVS's have been in use in South Africa since 1970 and have tested roads throughout South Africa. In this paper users' experience with the system is discussed. It is shown that it is a very effective and efficient means of applying axle loads.  Details of, and user experience with, HVS support equipment for collecting data are also discussed.  Finally the benefits of HVS testing accrued over the past years are summarized.  (Author/TRRL)]]></description>
      <pubDate>Tue, 30 Aug 1983 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/194626</guid>
    </item>
    <item>
      <title>THE WAVE PROPAGATION METHOD. A RELIABILITY STUDY</title>
      <link>https://trid.trb.org/View/194627</link>
      <description><![CDATA[When using the wave propagation method for bearing capacity measurements the rate of wave propagation of the different layers and the subgrade are obtained.  Since wave propagation is related to the elastic parameters of the pavement structure, valuable information is obtained about the different layers, which can be used for analysis of the strain in the surfacing.  However, it is not always possible to ascribe different curve branches of the dispersion curves to the appropriate road layers, when measurements are made on the road surface only.  In the present study measurements were also made on surfaces exposed by excavation of the road structure, thereby removing the layers one at a time. The analysis shows good agreement between propagation rates measured on the road surface and on exposed layers.  An exception was a test section having a cement stabilized layer, which had cracked, and to which the simple theory could therefore not be applied.  The study also showed that the pressure exerted by the overlaying layers had a considerable importance for the elastic layer moduli, and especially the modulus of the subgrade surface.  The latter is important in conjunction with thickness design based upon in situ measurement of subgrade bearing capacity.  The penetration depth of elastic waves is usually assumed to be 1/2-1/3 of the wave length, an assumption which was not confirmed in the present study.  The depth was found to be considerably less but this does not impair the applicability of the method to the analysis of typical road structures. (Author/TRRL)]]></description>
      <pubDate>Tue, 30 Aug 1983 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/194627</guid>
    </item>
    <item>
      <title>CORRELATING SPANISH FIELD MEASUREMENTS WITH THE FALLING WEIGHT DEFLECTOMETER</title>
      <link>https://trid.trb.org/View/194628</link>
      <description><![CDATA[During the last year, an experimental research was carried out using the falling weight deflectometer and the Benkelman beam, the most common device widely used in surveying the bearing capacity of a road and in designing strengthening layers in Spain.  This paper deals with the suitability of the falling weight deflectometer kuab 81 for these purposes and with the relation found between the deflections obtained with both types of equipment.  (Author/TRRL)]]></description>
      <pubDate>Tue, 30 Aug 1983 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/194628</guid>
    </item>
    <item>
      <title>CORRELATION OF ROAD RATER AND BENKELMAN BEAM DEFLECTIONS</title>
      <link>https://trid.trb.org/View/194629</link>
      <description><![CDATA[The Benkelman beam is commonly used to measure surface deflections of highway and airfield pavements.  The Benkelman beam is based on a simple lever-arm principle and uses dial gauges to measure surface deflections under an applied axle load.  The road rater is an electro-hydraulic testing device that applies a sinusoidal force to the pavement at a fixed amplitude and frequency; surface wave velocities are measured and electronically integrated to obtain surface deflections.  Road rater and Benkelman beam deflections have been successfully simulated using elastic theory and the chevron n-layer computer program.  The analyses presented in this paper illustrate relationships between road rater deflections and the more commonly used Benkelman beam deflections.  (Author/TRRL)]]></description>
      <pubDate>Tue, 30 Aug 1983 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/194629</guid>
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