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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>
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    <item>
      <title>How to Assign Nonlinear Anisotropic Modulus Model Parameters for Mechanistic Analyses of Unbound Aggregate Pavement Layers</title>
      <link>https://trid.trb.org/View/2761050</link>
      <description><![CDATA[Granular base materials used in pavement systems exhibit anisotropic and nonlinear stress-dependent behavior, characterized through the Mechanistic-Empirical Pavement Design Guide (MEPDG) or Uzan-type models using nine nonlinear model parameters (K₁ through K₉) related to the horizontal, vertical, and shear resilient moduli. As part of the development of the U.S. Army Corps of Engineers’ flexible pavement analysis program (C-FLEX) based on the finite element method, the MEPDG and Uzan models have been incorporated into the Joint Evaluation and Design Integrated (JEDI) software framework to characterize granular base and subbase layers. However, deriving these model parameters from standard resilient modulus testing remains challenging, especially those for horizontal and shear resilient moduli. This study introduces a methodology to establish nonlinear anisotropic resilient modulus parameters for the MEPDG model using triaxial test data generated with an advanced test apparatus with multi-directional pulsing capabilities. This method builds on previous work and provides for the MEPDG model regression-based relationships between material properties and anisotropic resilient moduli. Multiple datasets from various data sources were used to develop the guidelines presented in this paper for deriving horizontal (K₁ to K₃) and shear (K₇ to K₉) modulus model parameters based on vertical modulus model parameters (K₄ to K₆). The outcome includes recommended K₁ through K₉ for aggregate materials of varying quality, intended for implementation in the JEDI software to support nonlinear anisotropic stiffness characterization of unbound aggregate layers for mechanistic-empirical pavement design.]]></description>
      <pubDate>Wed, 19 Aug 2026 09:25:56 GMT</pubDate>
      <guid>https://trid.trb.org/View/2761050</guid>
    </item>
    <item>
      <title>Numerical simulation of time-dependent performance of jacked piles in marine clays: Considering anisotropy and destructuration</title>
      <link>https://trid.trb.org/View/2660770</link>
      <description><![CDATA[Accurately predicting the setup of jacked piles in marine soft clays is crucial for effective construction, load-bearing design, and maintenance of offshore foundations. This paper integrated UMAT subroutines into the ABAQUS platform using two numerical integration methods: the cutting plane algorithm (CPA) and the Newton-Raphson iterative algorithm (NRIA), to simulate the entire life cycle of jacked piles in marine soft clays. The study incorporates the advanced elastoplastic constitutive model (S-CLAY1S) and the elastoviscoplastic constitutive model (ANICREEP), addressing soil fabric anisotropy, structural effects, and, specifically, soil creep effects in the ANICREEP model. A two-dimensional axisymmetric model is established for jacked piles in marine soft clays, involving unloading and consolidation stages, followed by static load tests on test piles at various post-installation rest periods to assess their time-dependent bearing performance. Finite element modeling enables simulations of field and laboratory pile tests, validating models against measurements. Parameter analysis includes variations in excess pore water pressure (EPWP), ultimate skin friction resistance, and pile bearing capacity in both soil models, examining the impact of initial soil structure ratio on pile performance. Key findings reveal differences in EPWP dissipation rates and long-term bearing capacity evolution between elastoplastic and elastoviscoplastic soils, highlighting the ANICREEP model's capability to capture both short-term and creep-induced long-term effects. Integrating complex soil mechanics into ABAQUS enhances the ability to predict and optimize jacked pile performance in various geotechnical engineering applications.]]></description>
      <pubDate>Wed, 22 Apr 2026 16:13:42 GMT</pubDate>
      <guid>https://trid.trb.org/View/2660770</guid>
    </item>
    <item>
      <title>Numerical limit evaluations of the pullout capability of vertical strip plate anchor in anisotropic soil</title>
      <link>https://trid.trb.org/View/2649731</link>
      <description><![CDATA[The effectiveness of plate anchors in anisotropic soil conditions are essential for the design of both offshore and onshore foundation systems. This study presents a thorough numerical limit analysis to assess the pullout capacity of vertical strip plate anchors embedded in anisotropic soil. Using lower and upper bound limit analysis methods through finite element modeling, how strength anisotropy, embedment depth, and soil layering affect anchor performance is rigorously examined. The results show a clear sensitivity of the pullout capacity to the degree and orientation of anisotropy. This highlights the limitations of isotropic assumptions in some geotechnical design cases. Parametric studies further explain the relationship between anisotropic strength parameters and anchor resistance. These insights can improve stability and safety margins. These findings deepen the understanding of anchor–soil interaction under complex conditions and aid in crafting more accurate and efficient design methods for geotechnical engineers.]]></description>
      <pubDate>Fri, 03 Apr 2026 12:12:46 GMT</pubDate>
      <guid>https://trid.trb.org/View/2649731</guid>
    </item>
    <item>
      <title>Quantifying the anisotropic electrical resistivity of marine clays: A comprehensive model integrating index properties, gradation, and aging effects</title>
      <link>https://trid.trb.org/View/2685344</link>
      <description><![CDATA[Archie's cementation exponent (m) is a critical parameter for the resistivity-based characterization of marine sediments, as it enables the accurate estimation of porosity or void ratio profiles essential for offshore foundation design. However, its quantification remains challenging due to the complex anisotropic fabric of natural clays. This study investigated directional electrical behavior by combining laboratory experiments, ridge regression modeling, and field validation. Results on representative commercial clays (three kaolins and four bentonites) demonstrate that m is primarily governed by intrinsic index properties, with a log-linear model achieving high predictive accuracy (RMAE <7%). Validation using seabed clays from South Korea revealed that intrinsic properties alone are insufficient for natural deposits. This study identified that particle size distribution significantly enhances pore-path complexity; thus, incorporating gradation-related parameters in the model reduced the RMAE for remolded field samples to 8.6%. Furthermore, a time-dependent aging correction factor was introduced to account for long-term fabric development, reducing RMAE for undisturbed specimens from 40.7% to 18.6%. Finally, this study established that electrical anisotropy (λe) is a robust geophysical metric for assessing sample disturbance, with λe ranging 1.22-1.34 identified for boundary between intact and disturbed fabric. This framework supports reliable resistivity-based characterization for critical offshore infrastructure design.]]></description>
      <pubDate>Fri, 27 Mar 2026 10:14:49 GMT</pubDate>
      <guid>https://trid.trb.org/View/2685344</guid>
    </item>
    <item>
      <title>Influence of anisotropy on structural dynamic response, from the views of mechanism, analysis method, and implications for pavement design</title>
      <link>https://trid.trb.org/View/2643590</link>
      <description><![CDATA[While anisotropic properties of road materials have been extensively investigated, their systematic integration into pavement design frameworks remains incomplete. This study systematically reviews the mechanisms, characteristics and structural implications of material anisotropy in pavement systems through a layered analysis approach (asphalt surface, base and subgrade). The work evaluates three critical dimensions: experimental metrics and characterisation methods for anisotropy quantification, analytical techniques integrating anisotropic behaviour in structural design and anisotropy-induced performance degradation mechanisms. Key findings reveal that compressive modulus predominates as the primary anisotropy indicator in existing studies. Structural consequences include asphalt layer anisotropy exacerbating rutting severity and fatigue deterioration, base layer anisotropy diminishes pavement stress resistance and subgrade anisotropy amplifying permanent deformation. The paper concludes with the following research priorities: mechanistic modelling of anisotropy genesis and its evaluation protocols, field testing innovations for anisotropy assessment and inverse analysis methodologies for parameter identification. This synthesis establishes a foundational framework for advancing anisotropy-aware pavement engineering practices.]]></description>
      <pubDate>Mon, 05 Jan 2026 14:53:16 GMT</pubDate>
      <guid>https://trid.trb.org/View/2643590</guid>
    </item>
    <item>
      <title>Anisotropy in motion sickness susceptibility during longitudinal and lateral motion while seated on a car seat</title>
      <link>https://trid.trb.org/View/2608513</link>
      <description><![CDATA[Motion sickness is critical in automated vehicle design, particularly as horizontal accelerations become more variable and pronounced. However, even within horizontal translation, whether sickness sensitivity differs between longitudinal and lateral directions remains unclear. To investigate this, we conducted a within-subjects experiment with 21 participants exposed to repeated sinusoidal accelerations while seated in a car seat without visual cues, restrained by seat belt and neck brace. Each participant experienced one combination of two acceleration levels and multiple frequencies (0.15, 0.20, 0.25, or 0.40 Hz for 3.0 m/s²; 0.15, 0.25, or 0.40 for 0.65 m/s²). Symptoms were assessed using the Motion Illness Symptoms Classification at 1-min intervals. Results revealed significantly greater symptom progression in longitudinal motion (adjusted-mean: 3.0, max: 4.75) than lateral motion (adjusted-mean: 1.67, max: 2.65), despite smaller head angular velocities. These findings provide empirical evidence for direction-specific sickness sensitivity and underscore the need to consider motion direction in vehicle design.]]></description>
      <pubDate>Tue, 02 Dec 2025 09:56:41 GMT</pubDate>
      <guid>https://trid.trb.org/View/2608513</guid>
    </item>
    <item>
      <title>An Anisotropic Traffic Flow Model with Look-Ahead Effect for Mixed Autonomy Traffic</title>
      <link>https://trid.trb.org/View/2630571</link>
      <description><![CDATA[In this paper we extend the Aw–Rascle–Zhang (ARZ) non-equilibrium traffic flow model to take into account the look-ahead capability of connected and autonomous vehicles (CAVs), and the mixed flow dynamics of human-driven and autonomous vehicles. The look-ahead effect of CAVs is captured by a non-local averaged density within a certain distance (the look-ahead distance). We show, using wave-perturbation analysis, that increased look-ahead distance loosens the stability criteria. Our numerical experiments, however, showed that a longer look-ahead distance does not necessarily lead to faster convergence to equilibrium states. We also examined the impact of spatial distributions and the market penetrations of CAVs and showed that increased market penetration helps to stabilize mixed traffic while the spatial distribution of CAVs has less effect on stability. The results revealed the potential to use CAVs to stabilize traffic and may provide qualitative insights into speed control in the mixed autonomy environment.]]></description>
      <pubDate>Wed, 26 Nov 2025 09:24:14 GMT</pubDate>
      <guid>https://trid.trb.org/View/2630571</guid>
    </item>
    <item>
      <title>Thermal Influence of Physical Parameters of Additively Manufactured Windings in Permanent Magnet Synchronous Motors</title>
      <link>https://trid.trb.org/View/2603953</link>
      <description><![CDATA[For permanent magnet synchronous motor (PMSM), additively manufactured (AM) windings with variable cross-sectional shapes offer significant advantages in enhancing the slot fill factor and thermal properties, thereby contributing to an increase in power density. This article presents a thermal model for AM windings of PMSM that accounts for the anisotropy of the equivalent insulation thermal conductivity at various locations within the slot. This model improves the accuracy of the predicted winding temperature rise. The physical parameters of AM windings can be controlled by modifying the printing parameters and postprocessing conditions. The impact of electrical conductivity, thermal conductivity, and winding insulation parameters on the losses and temperature rise of PMSMs at various frequencies is then investigated. Finally, the temperature rise characteristics of the prototype PMSMs with the AM windings and the conventional windings are tested and compared, thereby confirming the validity of the thermal model for AM windings as well as their superior thermal properties.]]></description>
      <pubDate>Mon, 24 Nov 2025 10:24:54 GMT</pubDate>
      <guid>https://trid.trb.org/View/2603953</guid>
    </item>
    <item>
      <title>Effects of non-homogeneity and anisotropy in the bearing capacity of geosynthetics-reinforced soil-strip foundations under unsaturated conditions</title>
      <link>https://trid.trb.org/View/2606890</link>
      <description><![CDATA[The ultimate bearing capacity of foundations is a key factor in ensuring the safety and reliability of critical transportation infrastructure. Field evidence shows that subgrade soils are often unsaturated, spatially variable, and anisotropic. However, most existing studies on reinforced soil foundations neglect these features, which can lead to notable discrepancies between theoretical predictions and actual performance. To address this gap, the present study develops a comprehensive framework for evaluating the bearing capacity of reinforced soil foundations. The approach incorporates the effects of soil anisotropy and non-homogeneity on effective cohesion, and introduces an anisotropic soil–water characteristic curve model to capture their influence on hydraulic behavior. Analytical expressions are derived for the shear strength at the reinforcement–soil interface, explicitly accounting for heterogeneity and anisotropy, and a depth-dependent failure mechanism is established. The ultimate bearing capacity is then obtained through the framework of the upper bound theorem. Results highlight that both soil non-uniformity and anisotropy strongly affect the bearing capacity and the optimal reinforcement embedment depth. The proposed method provides a practical and reliable reference for designing reinforced foundations in complex geological environments.]]></description>
      <pubDate>Mon, 24 Nov 2025 10:23:27 GMT</pubDate>
      <guid>https://trid.trb.org/View/2606890</guid>
    </item>
    <item>
      <title>Dem investigation of volumetric loss-induced failure mechanisms and soil arching evolution in inherent anisotropic sandy soil strata</title>
      <link>https://trid.trb.org/View/2601801</link>
      <description><![CDATA[Soil arching effect induced by volumetric loss frequently leads to stress redistribution of sandy soil, even resulting in surface subsidence hazards. To systematically investigate the formation and evolution mechanisms of soil arches in inherent anisotropy strata, this paper conducts a set of anisotropic granular packing prepared for trapdoor tests with the objective of examining the effect of bedding angles (α) in sandy soil on the arching effect by employing the Discrete Element Method (DEM). This investigation systematically presents outcomes encompassing load–displacement curves, arching deformation patterns, and ground response within formations featuring distinct α. Furthermore, microscopic analyses are further adopted to endeavor to elucidate the behaviors influenced by α. Results indicate that under low fill heights, the specimen withα = 0° inclination exhibits a higher minimum load compared to others, attributed to increased bending moments generated by contact forces within the shear band. Specimens withα = 30° and 60° inclinations demonstrate significant lateral shifts in their maximum surface settlement points, a behavior accurately captured by the modified Peck formula proposed in this study. Furthermore, a three-stage evolution curve of soil arching is introduced to characterize the failure modes of granular materials.]]></description>
      <pubDate>Fri, 07 Nov 2025 11:30:16 GMT</pubDate>
      <guid>https://trid.trb.org/View/2601801</guid>
    </item>
    <item>
      <title>Equivalent continuum modeling and computational analysis of wave-induced hydrodynamics of large floating structures with lattice cores</title>
      <link>https://trid.trb.org/View/2611613</link>
      <description><![CDATA[This study presents a novel large floating structure featuring face sheets and a lattice-core construction with interconnected slender members that exhibit adjustable lightweight and high-stiffness properties. The complex topology leads to multiaxial coupling anisotropic elasticity governed by interfacial continuity between the face sheets and core, which induces unrecognized wave–structure–member interactions. Conventional equivalent beam models fail to capture such coupled effects. To address these mechanical issues, we develop an equivalent anisotropic continuum model for this structure with a lattice core and an integrated computational fluid dynamic‒finite element (CFD‒FEM) computational framework, which is compared with numerical models and analytical solutions. Through quantitative numerical analysis, we reveal unique anisotropic stress transfer mechanisms and their effects on structural deformation and hydrodynamic characteristics. This framework provides a basis for developing anisotropic structures, enabling their future application in floating bridges and marine platforms.]]></description>
      <pubDate>Mon, 27 Oct 2025 09:36:50 GMT</pubDate>
      <guid>https://trid.trb.org/View/2611613</guid>
    </item>
    <item>
      <title>Model dimensional scale effects on molecular dynamics simulations of bituminous materials</title>
      <link>https://trid.trb.org/View/2595385</link>
      <description><![CDATA[Accurate asphalt molecular dynamics (MD) simulations are essential for predicting its thermal, mechanical, and rheological properties. However, commonly used small-scale models (40 Å cubic) usually lead to significant fluctuations in simulation results. The fluctuations diminish with increasing model size, indicating the scale-dependent convergence of simulation results, a phenomenon that hasn’t been systematically quantified in previous asphalt MD simulation studies. This study aims to investigate the convergence behavior and determine appropriate model sizes for key simulation parameters. Different sizes of cubic asphalt models based on AAA-1 and AAM-1 asphalt samples were constructed, and the simulation results were validated against experimental data. Results showed that as the model side length increased from 40 Å to 80 Å, the average density, solubility parameter, and shear viscosity gradually stabilized, approaching convergence beyond 60 Å. Structural stability also improved markedly, as evidenced by the radial distribution function. Diffusion coefficients increased by 42.8 % (AAA-1) and 11.8 % (AAM-1) as the model size grew to 60 Å, whereas the shear and Young’s modulus in small-scale models showed strong anisotropy and only converged at 80 Å. Therefore, the model side lengths of 80 Å are required for mechanical simulations, while 60 Å models are sufficient for simulations of the other five parameters above, balancing computational cost with predictive reliability. Compared to previous studies, this work fills a critical gap in understanding the effects of model dimensional scale on asphalt molecular simulations and provides a practical reference for selecting model sizes, enabling reliable and efficient asphalt MD simulations.]]></description>
      <pubDate>Wed, 22 Oct 2025 16:46:32 GMT</pubDate>
      <guid>https://trid.trb.org/View/2595385</guid>
    </item>
    <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>A Numerical Study on the Mechanical Response of Circular Tunnels Under Initial Anisotropic Stress Conditions</title>
      <link>https://trid.trb.org/View/2594157</link>
      <description><![CDATA[This study investigates the mechanical response of a circular tunnel excavated under various initial anisotropic stress conditions. The results are presented in terms of ground reaction curves (GRC), the influence of the stiffness-to-strength ratio of the rock mass, and the evolution of radial and tangential stresses. For an in situ stress ratio (K₀, defined as the ratio of horizontal to vertical stress) less than 1, the maximum deformation and tangential stress are higher at the tunnel sidewall. Conversely, for K₀ > 1, these effects are more pronounced at the tunnel crown, while the response is symmetric for K₀ = 1. The mechanisms for the observed behavior are discussed and supported by stress redistribution contour diagrams. Using the results, a statistical analysis is used to develop and validate a new, easy-to-use prediction equation for calculating tunnel strains at the sidewall and crown across a wide range of tunneling scenarios.]]></description>
      <pubDate>Wed, 24 Sep 2025 15:31:08 GMT</pubDate>
      <guid>https://trid.trb.org/View/2594157</guid>
    </item>
    <item>
      <title>Effect of Initial Stress Anisotropy on Small-Strain Properties of Fiber-reinforced Calcareous Sand</title>
      <link>https://trid.trb.org/View/2583378</link>
      <description><![CDATA[This research presents the effects of using glass fibers as an eco-friendly additive on the small-strain properties of calcareous sand, commonly found in coastal and land reclamation areas. A series of resonant column tests were conducted on Hormoz calcareous sand, reinforced with randomly distributed glass fibers, under isotropic and anisotropic stress conditions. The results showed that glass fibers increased the small-strain shear modulus. Moreover, with increasing confining pressure, the optimal fiber content decreased from 2% to 1% (by weight). The damping ratio slightly decreased with 2% fiber content but increased with 1%. Overall, both shear modulus and damping ratio were increased with an appropriate amount of glass fiber reinforcement. The results of all tests indicated that initial stress anisotropy increased the shear modulus. However, fiber content and initial stress anisotropy had a negligible effect on the normalized shear modulus. In this study, an empirical relationship was also proposed to estimate the ratio between the maximum shear modulus under anisotropic and isotropic stress conditions. This relationship was validated using a comprehensive laboratory dataset, and it was found to depend only on the initial stress anisotropy and to be independent of confining pressure, fiber content, particle shape, or void ratio.]]></description>
      <pubDate>Thu, 18 Sep 2025 09:47:02 GMT</pubDate>
      <guid>https://trid.trb.org/View/2583378</guid>
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