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    <title>Transport Research International Documentation (TRID)</title>
    <link>https://trid.trb.org/</link>
    <atom:link href="https://trid.trb.org/Record/RSS?s=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" rel="self" type="application/rss+xml" />
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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>
    <image>
      <title>Transport Research International Documentation (TRID)</title>
      <url>https://trid.trb.org/Images/PageHeader-wTitle.jpg</url>
      <link>https://trid.trb.org/</link>
    </image>
    <item>
      <title>Determination of cross-anisotropic elastic constants of in situ soils using joint application of seismic refraction and downhole surveys</title>
      <link>https://trid.trb.org/View/2594570</link>
      <description><![CDATA[The precise determination of anisotropic elastic constants in natural soils is important for various geotechnical and geological engineering applications. This study presents a novel geophysical field approach for in situ measurement of these constants using the anisotropic components of P-wave and S-wave velocities. To achieve this, assuming cross-anisotropy in the soil deposits at a testing site, it was demonstrated that the propagation velocities of P- and S-waves in different directions and planes can be obtained through the joint application of seismic refraction and downhole surveys. The acquired refraction data were processed to calculate the velocities of the P-wave horizontal component (VPH), S-wave vertical component (VSV), and S-wave horizontal components (VSH) using Seismic Refraction Tomography (SRT), Multichannel Analysis of Surface Rayleigh Waves (MASW), and Multichannel Analysis of Love Waves (MALW), respectively. Additionally, the velocities of vertical and oblique P-wave components (VPV and VPθ) were determined by analyzing the arrival times and travel distances of signals collected from downhole testing. These velocity values were then integrated with rigorous equations derived from the theory of elastic wave propagation, enabling the quantification of elastic constants at the site. The developed approach may act as a valuable tool for the in situ estimation of cross-anisotropic elastic constants of shallow geomaterials based on field seismic techniques.]]></description>
      <pubDate>Fri, 17 Oct 2025 09:23:36 GMT</pubDate>
      <guid>https://trid.trb.org/View/2594570</guid>
    </item>
    <item>
      <title>Design of a Wiper as Compliant Mechanisms with a Monolithic Layout</title>
      <link>https://trid.trb.org/View/1760661</link>
      <description><![CDATA[

The increasingly important need to design simpler structures, reducing the number of constituent components, has motivated the approach outlined in this article, which proposes an effective reengineering example of a product belonging to the automotive industry, combining the advantages offered by the compliant mechanisms with production opportunities linked to the use of additive manufacturing. Taking advantage of compliant mechanisms makes it possible to significantly improve the component’s production phase, leading to undoubted benefits on the supply chain and on product’s time to market, benefits made possible by exploiting the outstanding characteristic of additive manufacturing to produce already assembled multi-material structures. The performances of the innovative monocomponent wiper designed here were compared, with the help of finite element method (FEM) simulations, with those of the component made in the traditional way and with those of the only other existing single-component frame of which we have news, the one patented by the United States (US) company Flexsys, obtaining satisfactory results both in terms of weight reduction, for the best pressure distribution at the wiper/glass interface, and in terms of maximum stress reduction.
]]></description>
      <pubDate>Wed, 21 Apr 2021 16:16:25 GMT</pubDate>
      <guid>https://trid.trb.org/View/1760661</guid>
    </item>
    <item>
      <title>Implementing General Power Law to Interconvert Linear Viscoelastic Functions of Modified Asphalt Binders</title>
      <link>https://trid.trb.org/View/1502172</link>
      <description><![CDATA[Interconversion between the relaxation modulus and creep compliance, which forms a constitutive linear viscoelastic function for asphalt binders, is a classical challenge, even when such a constitutive function is required to be determined at low temperatures based on the bending beam rheometer (BBR) test. Adopting the general power law, a new method was introduced that could precisely fulfill such an interconversion at low temperatures for BBR test data. In order to verify the proposed method, an experimental program was performed on a neat asphalt binder and two modified asphalt binders using crumb rubber and polyphosphoric acid (PPA) individually. Material characteristics were determined from the test data, and they were applied in a numerical framework to simulate BBR test behavior. To ensure the accuracy of using the general power law for interconversion, the results of this approach are compared with well-known approaches introduced by Hopkins and Hamming and Park and Schapery. Numerical results have shown good agreement with the test data.]]></description>
      <pubDate>Thu, 22 Mar 2018 12:03:05 GMT</pubDate>
      <guid>https://trid.trb.org/View/1502172</guid>
    </item>
    <item>
      <title>Strain Gage Rosette Measurements in Molded Plastic Parts</title>
      <link>https://trid.trb.org/View/1250531</link>
      <description><![CDATA[The paper presents the strain gage rosette measurements on polypropylene molded parts. The strain measurement on a plastic or composite test object will frequently call for much greater skill, expertise, and know ledge of mechanics than that typically required with the structural metals. The characterization of plastics for engineering purposes necessitates considerably more testing than is typical for metals primarily because of time, temperature, moisture, and aging effects on the material behavior. With the increasing number of plastic structural components, it can be expected that the need to measure service strains on these materials will increase correspondingly and the strain gage application technology must be advanced accordingly. It is very important for plastic materials to determine the Young’s modulus and the Poisson’s ratio using the strain gage rosette.]]></description>
      <pubDate>Wed, 22 May 2013 11:17:48 GMT</pubDate>
      <guid>https://trid.trb.org/View/1250531</guid>
    </item>
    <item>
      <title>Subgrade Support Characteristics; Experimental and Theoretical : Progress Report No. 1</title>
      <link>https://trid.trb.org/View/1219492</link>
      <description><![CDATA[The purpose of this report was to: develop mobile, sensitive, simple to operate equipment that will record the deflections of concrete pavement; to attempt to determine, in terms of elastics and damping constants, the relative support characteristics of the nine concrete highway sub-base subgrade system, located on U.S Highway 41 near Cook, Indiana; to record the changes in surface contour of the nine concrete highway subgrade sub-base systems as loaded vehicles are driven over them; to attempt to analytically solve the problem of a concrete highway on a damped elastic foundation.]]></description>
      <pubDate>Thu, 13 Dec 2012 09:26:17 GMT</pubDate>
      <guid>https://trid.trb.org/View/1219492</guid>
    </item>
    <item>
      <title>A Study of the Use of the Poisson's Ratio as a Constitutive Parameter for Viscoelastic Analysis of Asphaltic Mixtures</title>
      <link>https://trid.trb.org/View/1147586</link>
      <description><![CDATA[A study of the use of the Poisson's ratio as a constitutive parameter for asphalt mixtures is presented. The literature review shows that experimental results of Poisson's ratio in asphalt mixes are very scattered and are also stress/load dependent. Experimental evidences show the impossibility to obtain a constant Poisson's ratio for viscoelastic materials, and a mathematical treatment of the problem shows that the viscoelastic Poisson's ratio is time-dependent, path-dependent, and impossible to use in the correspondence principle. The substitution of the use of Poisson's ratio for the use of the compliances C11(t) and C12(t) as constitutive parameters is proposed, and the experimental and theoretical advantages shown. Dynamic modulus and Indirect Tensile Tests were simulated, comparing displacements using C11(t) and C12(t), and C11(t) and constant Poisson's ratio. Using C11(t) and C12(t) increased the degree of viscoelasticity in the material on both simulated tests. Such behavior depends on the temperature, which was also verified.]]></description>
      <pubDate>Wed, 22 Aug 2012 15:36:43 GMT</pubDate>
      <guid>https://trid.trb.org/View/1147586</guid>
    </item>
    <item>
      <title>Layer Moduli of Nebraska Pavements for the New Mechanistic-Empirical Pavement Design Guide (MEPDG)</title>
      <link>https://trid.trb.org/View/1090851</link>
      <description><![CDATA[As a step-wise implementation effort of the Mechanistic-Empirical Pavement Design Guide (MEPDG) for the design and analysis of Nebraska flexible pavement systems, this research develops a database of layer moduli — dynamic modulus, creep compliance, and resilient modulus — of various pavement materials used in Nebraska. The database includes all three design input levels. Direct laboratory tests of the representative Nebraska pavement materials are conducted for Level 1 design inputs, and surrogate methods, such as the use of Witczak’s predictive equations and the use of default resilient moduli based on soil classification data, are evaluated to include Level 2 and/or Level 3 design inputs. Test results and layer modulus values are summarized in Appendices. Modulus values characterized for each design level are then input into the MEPDG software to investigate level-dependent performance sensitivity of typical asphalt pavements. The MEPDG performance simulation results then reveal any insights into the applicability of different modulus input levels for the design of typical Nebraska pavements. Significant results and findings are presented in this report.]]></description>
      <pubDate>Wed, 16 Feb 2011 13:42:18 GMT</pubDate>
      <guid>https://trid.trb.org/View/1090851</guid>
    </item>
    <item>
      <title>Determination of Viscoelastic Poisson's Ratio and Creep Compliance from the Indirect Tension Test</title>
      <link>https://trid.trb.org/View/899107</link>
      <description><![CDATA[The indirect tension test has received extensive attention due to its capability to test field cores from thin asphalt layers. For that reason, the fundamental viscoelastic material property, creep compliance, or complex modulus has been determined by employing the indirect tension testing system. However, if the creep compliance or complex modulus is to be determined from such a multiaxial testing mode, another crucial material property must be introduced, that is, Poisson's ratio. It is well known that the Poisson's ratio of a viscoelastic material is a function of time or frequency; nevertheless, it has been commonly assumed to be a constant and a time- or frequency-independent property. In this study, computation algorithms for determining the time- and frequency-dependent Poisson's ratio of asphalt mixtures were developed based on the theory of viscoelasticity. From the comparative study, it was found that the Poisson's ratio determined from the frequency domain corresponded well to that determined from the time domain. Further study performed on the sensitivity of Poisson's ratio clearly showed that the time-dependent Poisson's ratio was an important property in determining accurate creep compliance, and an inappropriate assumption for Poisson's ratio overestimated or underestimated the measured creep compliance.]]></description>
      <pubDate>Mon, 31 Aug 2009 09:24:20 GMT</pubDate>
      <guid>https://trid.trb.org/View/899107</guid>
    </item>
    <item>
      <title>CES - Production Functions of Transport Sectors of Germany</title>
      <link>https://trid.trb.org/View/883829</link>
      <description><![CDATA[This paper analyzes the transport sectors of Germany between the years 1990 and 2002. Therefore, production functions are estimated and the development of input and investment coefficients are analyzed. Based on statistics two transport vehicle sectors and five transport service sectors can be differentiated. A constant elasticity of scale (CES) production function is used. The production function does not consider only capital and labor but also R&D expenditures on a sector level. The results enable to compare the transport sectors. Labor/capital intensive sectors, sectors with a high/low technical progress or high/low substitution elasticity’s may be distinguished.]]></description>
      <pubDate>Thu, 19 Feb 2009 14:43:35 GMT</pubDate>
      <guid>https://trid.trb.org/View/883829</guid>
    </item>
    <item>
      <title>Nonrecovered Compliance from Dynamic Oscillatory Test vis-a-vis Nonrecovered Compliance from Multiple Stress Creep Recovery Test in the Dynamic Shear Rheometer</title>
      <link>https://trid.trb.org/View/875001</link>
      <description><![CDATA[Nonrecovered compliance is presently being viewed as the most appropriate rheological parameter for evaluating the propensity of an asphalt binder to resist permanent deformation or rutting in the pavement wheel paths. The nonrecovered compliance can be obtained in two ways using two different types of tests in the dynamic shear rheometer. One is through the dynamic oscillatory test using a frequency, time, strain or stress sweep, wherein the data generated is in terms of the complex modulus and phase angle that can be used in a proper mathematical form to obtain the nonrecovered compliance. The other is through the multiple stress creep and recovery test wherein the nonrecovered strain at each stress level after 10 cycles of creep and recovery is divided by the stress value to obtain the nonrecovered compliance. The two methods are very different in the way data gets generated and handled and, also, in the level of ease or difficulty in data generation. With two methods competing to come up with the same outcome, it is important to see a comparison of the merits and demerits of each of the methods in order to ascertain which of the two is more reliable, more fundamental, easier to use and better to implement. The purpose of this paper is to provide a one-on-one comparison between the two methods using the same set of binders and also to look at the possible benefits of one over the other.]]></description>
      <pubDate>Sat, 29 Nov 2008 08:06:28 GMT</pubDate>
      <guid>https://trid.trb.org/View/875001</guid>
    </item>
    <item>
      <title>Closure to "Three-Dimensional Responses of a Tied-Back Excavation through Clay" by Richard J. Finno and Jill F. Roboski</title>
      <link>https://trid.trb.org/View/794237</link>
      <description><![CDATA[In regard to the magnitude of the preload, the authors note that quantification of the relative merits of prestressing the ground anchors at either 75% or 100% of the design load is difficult. In their paper, the authors report that the first two level of ground anchors, located in beach sand, were nearly at the same elevation. This was physically possible only because the contractor horizontally staggered the anchors in these two rows. The authors further state that in order to evaluate response differences that are strictly the result of differences in the prestress, one would need excessively detailed three-dimensional numerical analyses. The authors cite Finno et al. (2002) regarding presentation of data from instrumented anchors collected at a different Chicago excavation. Results show that the anchors, locked off at 100% of the design loads, remained essentially constant throughout the excavation. As for the discusser's query about optimal prestress value, the authors are unaware of any supporting numerical studies or performance data.]]></description>
      <pubDate>Tue, 28 Nov 2006 10:11:12 GMT</pubDate>
      <guid>https://trid.trb.org/View/794237</guid>
    </item>
    <item>
      <title>EXPERIMENTALLY DETERMINED KEY CURVES FOR FRACTURE SPECIMENS</title>
      <link>https://trid.trb.org/View/755538</link>
      <description><![CDATA[For many years, researchers have been developing key curve and normalization function methods to estimate crack extension in standard elastic-plastic fracture toughness test geometries for ferritic structural steels.  This study develops a compliance ratio (CR) method to determine key curves for predicting crack extension.  First, a statically loaded source specimen with the unloading compliance procedure specified in ASTM 1820 is constructed.  Second, the so-called CR load-displacement curve is calculated for the source specimen, which is the load-displacement record that would have been obtained if the crack had not extended.  Third, non-dimensionalizing the CR load by the maximum load and the displacement by the elastic displacement at the maximum load from the source specimen yields the adjusted key curve.  Analysis of extensive data shows that the key curve is independent of notch type, initial crack length and temperature.  However, it is dependent on specimen size and steel type.  Assuming that the key curves of the source and target specimens are the same, the compliance of the target specimens are calculated with a reverse application of the CR method, and the crack length is obtained using the equations in ASTM E1820.  The CR method has been successfully applied to dynamically loaded specimens and has been found to be much simpler than the normalization method described in Annex A15 of ASTM 1820.]]></description>
      <pubDate>Tue, 12 Apr 2005 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/755538</guid>
    </item>
    <item>
      <title>EFFECT OF Z-PINS ON FRACTURE IN COMPOSITE COCURED DOUBLE CANTILEVER BEAMS</title>
      <link>https://trid.trb.org/View/748533</link>
      <description><![CDATA[The paper illustrates a new approach to the evaluation of the effect of z-pins on deformations and the strain energy release rate in composite double cantilever beams (DCB) subject to a standard fracture toughness test. The effect of z-pins is modeled by an elastic foundation, based on previously published work. The approach to the solution is based on a separate analysis of the intact and delaminated parts of DCB. The rotational stiffness of the intact part is obtained from the Rayleigh-Ritz solution for this part subjected to a force couple, rather than modeling the rotational restraint by introducing an elastic foundation, as has been done in the previous studies. Subsequently, the deformation of the delaminated part of DCB is analyzed exactly by solving the equation of equilibrium with the appropriate boundary conditions. Based on this solution, the compliance, the rate of change of compliance, and the strain energy of the specimen can be evaluated. The results illustrate the beneficial effect of z-pins on the resistance of DCB to delamination cracking.]]></description>
      <pubDate>Tue, 18 Jan 2005 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/748533</guid>
    </item>
    <item>
      <title>DETERMINATION OF EMBANKMENT DENSITY BY THE SEISMIC METHOD</title>
      <link>https://trid.trb.org/View/119384</link>
      <description><![CDATA[THE APPLICATION OF SEISMIC TECHNIQUES FOR THE MEASUREMENT OF SOIL DENSITY IN CONSTRUCTION CONTROL WAS EXAMINED BY EXTENSIVE FIELD WORK ON ACTUAL EMBANKMENT CONSTRUCTION PROJECTS. MEASUREMENTS OF SOIL DENSITY AND SEISMIC WAVE VELOCITY WERE OBTAINED FROM TEST PLATFORMS EACH OF WHICH WAS TESTED AT THREE STATES OF COMPACTION, LOOSE, INTERMEDIATE & HIGHLY COMPACT. A SIMPLE LINEAR RELATIONSHIP BETWEEN VELOCITY AND DENSITY WAS EXPECTED. THE RAW FIELD DATA SHOW THAT' /1/ INDIVIDUAL SOILS CANNOT BE GROUPED TO AFFORD SIMPLE CORRELATION OF VELOCITY WITH DENSITY, /2/ THE RELATION BETWEEN VELOCITY AND DENSITY FOR A GIVEN SOIL IS OF A PARABOLIC--NOT LINEAR--CHARACTER IN THE RANGE OF INTEREST, AND /3/ THE ELASTIC CONSTANTS OF SOILS ARE FAR MORE VARIABLE THAN ORIGINALLY SUPPOSED, AND FAR MORE IMPORTANT THAN SMALL CHANGES IN DENSITY. THE THEORY OF WAVE PROPAGATION IN ELASTIC BODIES WAS INVESTIGATED WITH REGARD TO DEGREE OF CORRESPONDENCE WITH FIELD DATA ON COMPACTED SOILS. DENSITY MEASUREMENTS BY THREE DIFFERENT METHODS WERE STUDIED IN RELATION TO SCATTER IN VALUES IN EXCESS OF THE RANGE OF PRECISION KNOWN FOR THE METHODS. AN ENTIRELY NEW APPROACH TO COMPACTION EMERGED, BASED UPON THE SOIL RESPONSE TO DYNAMIC WAVE PROPAGATION. THE COMPACTION PROCESS IS A PROCESS OF DENSIFICATION ONLY IN THE VERY EARLY STAGES. DENSITY CHANGES WITH FURTHER COMPACTION DIMINISH RAPIDLY WHILE THE ELASTIC MODULI BECOME SUBSTANTIALLY INCREASED. THE REPORT DISCUSSES THE UTILITY OF A DYNAMIC APPROACH TO EMBANKMENT PERFORMANCE AND VIEWS THE LATTER AS A CONSEQUENCE OF THE PRESENCE OR ABSENCE OF AN ELASTIC SOIL REPONSE TO DYNAMIC STRESSES IMPOSED IN SERVICE.]]></description>
      <pubDate>Sun, 15 Aug 2004 02:19:33 GMT</pubDate>
      <guid>https://trid.trb.org/View/119384</guid>
    </item>
    <item>
      <title>THE EFFECT OF ANISOTROPHY /SIC/ ON THE DETERMINATION OF DYNAMIC ELASTIC CONSTANTS OF ROCK</title>
      <link>https://trid.trb.org/View/118145</link>
      <description><![CDATA[A BRIEF REVIEW OF THE RESONANT FREQUENCY AND ULTRASONIC PLUS METHODS FOR OBTAINING ELASTIC CONSTANTS OF ROCK SAMPLES SHOWS THAT THE EQUATIONS FOR AN ISOTROPIC ELASTIC SOLID COMMONLY USED TO CALCULATE YOUNGS MODULUS, MODULUS OF RIGIDITY, AND POISSONS RATIO CAN RESULT IN APPRECIABLE ERROR IF THE ROCK IS EVEN SLIGHTLY ANISOTROPIC. CONSIDERATION OF THE EQUATIONS THAT RELATE BAR VELOCITIES AND FREE MEDIUM VELOCITIES TO ELASTIC CONSTANTS FOR ORTHOTROPIC, TRANSVERSELY ISOTROPIC, AND ISOTROPIC SOLIDS SHOWS THAT A COMBINATION OF THE 2 METHODS CAN BE USED TO DETERMINE AVERAGE ELASTIC CONSTANTS FOR A SINGLE SAMPLE OF ROCK. THE DETERMINATION OF ELASTIC CONSTANTS IN DIFFERENT DIRECTIONS REQUIRES A LARGE NUMBER OF TESTS ON ORIENTED SAMPLES. THE USE OF BOTH THE RESONANT FREQUENCY AND ULTRASONIC PULSE METHODS IS RECOMMENDED SO THAT THE DETERMINATION OF BOTH YOUNGS MODULUS AND MODULUS OF RIGIDITY IS INDEPENDENT OF THE DETERMINATION OF POISSONS RATIO. /AUTHOR/]]></description>
      <pubDate>Sun, 15 Aug 2004 01:48:15 GMT</pubDate>
      <guid>https://trid.trb.org/View/118145</guid>
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