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    <title>Transport Research International Documentation (TRID)</title>
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    <atom:link href="https://trid.trb.org/Record/RSS?s=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" rel="self" type="application/rss+xml" />
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    <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>
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      <link>https://trid.trb.org/</link>
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    <item>
      <title>Three-dimensional modelling of drag anchor penetration using the material point method</title>
      <link>https://trid.trb.org/View/2711244</link>
      <description><![CDATA[Drag embedment anchors are a key threat to buried subsea linear infrastructure, such as power/data cables and pipelines. For cables, selecting a burial depth is a compromise between protecting the cable from anchor strike and the increased cost of deeper installation. This paper provides an efficient large deformation, elasto-plastic Material Point Method-based soil–structure interaction predictive tool for the estimation of anchor penetration based on Cone Penetration Test (CPT) site investigation data. The tool builds on earlier work by the authors supplemented by three key developments: modelling assemblies of rigid bodies (necessary for articulated anchors), a partitioned domain approach to enable accurate and efficient modelling of long anchor pulls, and an improved means of modelling rotational inertia. The numerical model is calibrated using CPT data and then used to predict the penetration behaviour of two different drag anchors across a range of relative density sands under drained conditions with validation against scaled geotechnical centrifuge physical tests. Numerical simulations both confirm assumptions in, and identify key issues with, the UK Carbon Trust’s Cable Burial Risk Assessment (CBRA) approach for estimating anchor penetration. In particular, the results confirm that anchor penetration scales linearly with fluke length but also that the penetration of drag anchors is highly dependent on both the relative density of the sand and the full geometry of the anchor. The numerical model presented in this paper enables site-specific anchor-penetration assessment along cable routes and can be used to evaluate the performance of different anchor designs and sizes in varied soil conditions.]]></description>
      <pubDate>Mon, 08 Jun 2026 08:37:49 GMT</pubDate>
      <guid>https://trid.trb.org/View/2711244</guid>
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    <item>
      <title>Design and analysis of shared anchor layouts for floating wind farms in deep waters</title>
      <link>https://trid.trb.org/View/2661539</link>
      <description><![CDATA[As floating wind farms for the U.S. West Coast are currently being explored, this study provides reference mooring system designs and anchor loads for farms with shared anchors in deep water (850 m), based on a 15 MW turbine, a size currently being deployed. It offers a comprehensive analysis of two shared anchor layouts, governed by 3-line and 6-line shared anchors, with mooring systems designed to maintain a minimum turbine spacing of 2000 m.A detailed loads analysis assesses line tensions, shared anchor forces, and force directionality under various environmental conditions. Suction caissons are designed for two soil profiles based on the loads analysis. A mooring cost analysis compares 54-turbine farm layouts with shared anchors to a baseline layout without shared anchors.Results show that while the 6-line anchor experiences higher loads due to additional platform connections, it exhibits lower inclination angles and less variability compared to the 3-line anchor. Suction caisson designs are primarily influenced by net force magnitude and inclination angle, resulting in similar dimensions for both layouts due to their higher horizontal resistance. Farms with shared anchors demonstrate mooring cost reductions of up to 36% compared to the baseline, with the 6-line layout offering the lowest mooring system costs, albeit with only marginal differences compared to the 3-line layout. Overall, this study highlights how taut mooring systems with shared anchors impact anchor loads, mooring system footprints, and overall farm layout, providing valuable insights for future deep-water floating wind projects.]]></description>
      <pubDate>Mon, 27 Apr 2026 14:57:35 GMT</pubDate>
      <guid>https://trid.trb.org/View/2661539</guid>
    </item>
    <item>
      <title>Developing failure envelopes of strip anchors under combined V-H-M loadings using FELA and ADABoost models</title>
      <link>https://trid.trb.org/View/2660820</link>
      <description><![CDATA[This paper investigates the failure envelopes of horizontal strip anchors under combined V-H-M loading conditions in both 2D (H/suTCB, M/suTCB2) and 3D (V/Vult, H/suTCB, M/suTCB2) spaces. It examines how the anisotropy strength ratio (re) and anchor embedment ratio (D/B) affect the behavior of strip anchors in clays using adaptive finite element limit analysis (FELA). Additionally, this study presents a novel soft-computing approach by developing a machine learning model that incorporates the adaptive boosting (ADABoost) technique to create surrogate models for predicting the failure envelope of horizontal strip anchors. The proposed ADABoost model is accurate and validated against the numerical FELA results, providing engineers with a practical tool for establishing the failure envelope of a strip anchor in anisotropic clay under general V‒H‒M loadings. The findings of this study are expected to contribute innovative and reliable solutions for optimizing standard strip anchors under general loading conditions.]]></description>
      <pubDate>Thu, 23 Apr 2026 09:12:25 GMT</pubDate>
      <guid>https://trid.trb.org/View/2660820</guid>
    </item>
    <item>
      <title>Numerical study on the yield surface of plate anchors in clay: Effect of soil-anchor interface tension</title>
      <link>https://trid.trb.org/View/2661444</link>
      <description><![CDATA[The growing demand for floating offshore wind turbines in deep-water environments has increased reliance on plate anchors to provide holding capacity. These anchors are subjected to combined normal, sliding, and rotational moment loadings during drag-in installation, keying processes, and long-term service as permanent mooring systems. Most previous studies have evaluated the combined loading capacity yield surface of plate anchors by assuming a fully bonded soil-anchor interface, equivalent to infinite interface tension – an assumption that may be unconservative. This study investigates the uniaxial bearing capacities and combined loading yield surfaces of plate anchors in clay under varying soil-anchor interface tension conditions using finite element modelling. A comprehensive parametric study was performed, considering embedment depth, anchor thickness ratio, anchor roughness, and, critically, soil-anchor interface tension. The results show that the yield surface evolves disproportionately in three-dimensional loading space, with pronounced enlargement in the normal direction as interface tension increases, until a critical value is reached. Parameterised design equations are proposed for the yield surface, enabling straightforward evaluation of combined loading capacities under varying interface tension conditions.]]></description>
      <pubDate>Thu, 23 Apr 2026 09:12:25 GMT</pubDate>
      <guid>https://trid.trb.org/View/2661444</guid>
    </item>
    <item>
      <title>Failure Envelopes of Helical Anchors in Sand</title>
      <link>https://trid.trb.org/View/2657930</link>
      <description><![CDATA[Helical anchors have emerged as an attractive alternative supporting offshore floating structures due to their low noise installation, high pullout capacity, and potential reusability. This paper investigates large-diameter (Dh=1–2  m) helical anchors subjected to inclined pullout at the mooring line using a critical-state-compatible bounding surface sand plasticity model (Sanisand04) within a three-dimensional finite-element (3D-FE) framework. With careful numerical implementation of the sand model, validation studies were performed with comparisons with theoretical solutions from the literature. A range of sand densities of practical interests were explored while documenting the sand state and displacements surrounding the anchor under complex V−H (vertical-horizontal) loading conditions. The model successfully captures the transition from shallow to deep failure mechanisms and provides visual evidence of the sand mobilized zone under varying mooring load angles over the range of sand densities studied. The affected zone decreases with increasing embedment depth and increases with higher relative density. A stepwise calculation framework is proposed for routine assessment of the V−H failure envelope for a single-helix anchor. An existing anchor pullout model for shallow embedment is systematically extended to deep helical anchors, allowing quick estimation of the vertical pullout capacity.]]></description>
      <pubDate>Tue, 21 Apr 2026 14:30:16 GMT</pubDate>
      <guid>https://trid.trb.org/View/2657930</guid>
    </item>
    <item>
      <title>The impact velocity of gravity installed anchors released in air at different height, added mass and scale conditions</title>
      <link>https://trid.trb.org/View/2660623</link>
      <description><![CDATA[For various types of gravity installed anchor (GIA) that rely on free fall to penetrate the seabed, it is vital before installation to accurately evaluate the velocity that the anchor impacts the seabed. However, challenges are arising when facing emerging engineering developments: (1) the GIA has to be released in air to ensure a sufficient falling distance when the water is not deep enough; (2) to enhance the penetration of GIAs in sandy seabed, auxiliary techniques are considered to apply such as adding extra mass to the anchor; (3) compared to conventional GIAs in deep waters, the GIA with smaller size is more often an option for offshore floating applications, such as renewable energy developments. To deal with the varieties and complexities in evaluating the impact velocity, a systematic study is performed to explore the effects of different factors, including the anchor type, the release heights both in water and in air, the added mass, and the anchor scale. Three typical types of GIAs, namely the finless, T98 and OMNI-Max anchors, are selected in the present study. By combing theoretical and computational fluid dynamics (CFD) analyses, a unified explicit expression of the falling velocity of GIAs is derived in terms of multiple factors, which can be simply and quickly used to calculate the impact velocity of GIAs for various applications.]]></description>
      <pubDate>Tue, 21 Apr 2026 14:30:16 GMT</pubDate>
      <guid>https://trid.trb.org/View/2660623</guid>
    </item>
    <item>
      <title>An assessment of model parameters for offshore torpedo anchors</title>
      <link>https://trid.trb.org/View/2660604</link>
      <description><![CDATA[Torpedo anchors offer a fast and cost-effective solution for floating wind turbine moorings. However, the application of torpedo anchors outside Brazil remains limited due to insufficient design guidance and uncertainty in model parameters. Therefore, the key objective of this paper is to critically assess and provide appropriate model parameters for practical design, including the hydrodynamic and geotechnical models. The paper presents the hydrodynamic model, the penetration model, and the holding capacity model separately with both existing data in the literature and new data. The key findings are: (1) an equivalent system drag coefficient of 1.0 can be used in the hydrodynamic model for predicting the anchor impact velocity in water; (2) a soil strain-rate parameter of 0.123 and an added mass coefficient of 2.0 can be used in the penetration model for predicting the anchor final embedment; (3) a closed-form failure envelope under inclined loading is assessed to be appropriate for the anchor holding capacity. Uncertainties observed in laboratory tests and field installations during the various anchor design stages are covered by the suggested low to high estimates of the model parameters for practical design. The paper ends with discussions and recommendations for current practice and future studies.]]></description>
      <pubDate>Tue, 21 Apr 2026 14:30:16 GMT</pubDate>
      <guid>https://trid.trb.org/View/2660604</guid>
    </item>
    <item>
      <title>Numerical investigation of inclined loading and failure envelopes of helical anchors in clay over sand</title>
      <link>https://trid.trb.org/View/2679748</link>
      <description><![CDATA[Helical anchors are increasingly recognised as a promising anchoring solution for tethering offshore floating facilities, owing to their silent installation process and substantial pullout resistance. This paper examines the behaviour of helical anchors subjected to inclined loading in clay over sand deposits. The investigation was carried out through three-dimensional finite element analyses, employing the critical state-compatible bounding surface plasticity model for sand. The results were validated against published data from the literature. A series of parametric analyses were performed to investigate the influence of clay layer thickness, sand layer relative density, mudline loading inclination, and helix-to-pitch diameter ratio on the anchor performance. Compared with the single-layer sand case, the presence of an overlying clay layer significantly reduces the pullout capacity of helical anchors. The maximum vertical and horizontal capacities decrease by 80% and 90%, respectively. A framework is established for estimating the failure envelopes for helical anchors embedded in clay over sand deposits. Unlike existing approaches that mainly focus on vertical loading or homogeneous soil conditions, the proposed framework integrates the combined effects of load inclination and soil stratification. It can provide a practical and straightforward tool for engineering design applications.]]></description>
      <pubDate>Wed, 25 Mar 2026 11:44:47 GMT</pubDate>
      <guid>https://trid.trb.org/View/2679748</guid>
    </item>
    <item>
      <title>Experimental and numerical investigation of offset and trajectory during descent of a shell–line–anchor single-point mooring system</title>
      <link>https://trid.trb.org/View/2679740</link>
      <description><![CDATA[The exploration and development of marine resources, as well as advances in marine research, have drawn increasing attention to the deployment dynamics of underwater facilities in complex marine environments. In this study, the descent behavior of a single-point mooring (SPM) system, which consists of a shell structure, mooring lines and gravity anchors, was investigated through a combination of experiments and numerical simulations, and the motion characteristics of the system during the descent process were analyzed in detail. As the current velocity increases, the offset distance also increases significantly. This trend becomes more pronounced at greater depths. During the initial water entry stage, the unsteady motion of the shell reduces the deviation of the anchor, reducing the final offset distance by more than 20%. In addition, the coupling effect of the load ratio and the water depth has a significant impact on the descent trajectory. Under the two water depth conditions of 30 m and 150 m, the favorable parameter range for controlling the distance offset of the structure used in this study is: flow velocity 0-0.1 m/s, load ratio 40%-60%.]]></description>
      <pubDate>Wed, 25 Mar 2026 11:44:47 GMT</pubDate>
      <guid>https://trid.trb.org/View/2679740</guid>
    </item>
    <item>
      <title>Cyclic response analysis of suction anchors for floating wind turbine in clays under inclined loading</title>
      <link>https://trid.trb.org/View/2641290</link>
      <description><![CDATA[The mechanical behavior of the suction anchor for floating wind turbines under inclined cyclic loading is an essential consideration in their design. This study investigates the cyclic performance of suction anchors in clay using a modified kinematic hardening model, which considers the cyclic degradation effects of clay and is validated with centrifuge model tests. The effects of loading amplitude, loading frequency and loading sequence on the cumulative deformation of suction anchors and the soil degradation mechanism were systematically investigated. The results show that the cumulative displacement of the foundation will exhibit a noticeable ratcheting pattern when the loading exceeds the critical load. The motion pattern of the foundation gradually changes from an initial oblique upward to a vertical mode as the loading and frequency increase. The loading sequence has a significant effect on the displacements and motion pattern of the foundation, and is related to the maximum historical load applied. The soil degradation zone gradually develops from the foundation end tip to the external side of the foundation skirt as the loading and frequency increase, eventually forming a U-shape. The soil degradation degree can be quantitatively analyzed using a degradation index, which is proportional to the loading amplitude and frequency.]]></description>
      <pubDate>Wed, 11 Mar 2026 14:41:29 GMT</pubDate>
      <guid>https://trid.trb.org/View/2641290</guid>
    </item>
    <item>
      <title>Experimental study on the effect of shank geometry, relative density and drag velocity on the installation characteristics of drag anchors in sand</title>
      <link>https://trid.trb.org/View/2641252</link>
      <description><![CDATA[Drag embedment anchors (DEAs) are cost-effective and highly efficient mooring anchor solutions with significant potential for offshore applications. However, reliable methods for predicting the penetration trajectory and holding capacity of drag anchors in sand remain lacking, and experimental data on their behaviour are extremely limited. To fill this knowledge gap, this study investigates the installation mechanisms and key influencing factors of drag anchors in sand using a custom-developed model testing system. The effects of drag velocity, soil density and shank configuration on the penetrability and holding capacity of drag anchor are systematically examined. The experimental results demonstrate that excessively high drag velocities accelerate the development of the roll angle, thereby increase the risk of anchor roll-out failure. Furthermore, higher soil density leads to shallower penetration depth and reduced holding capacity. In addition, the shank geometry is found to play a critical role on the penetrability of drag anchor in sand. A single shank design as compared to conventional double shank design drastically increases the ultimate penetration depth and consequently the holding capacity. The experiments also reveal that greater embedment depth and holding capacity in looser sand or with the single shank anchor is associated with a lower stabilised pitch angle achieved at ultimate state. These findings provide valuable insights into the mechanisms governing drag anchor installation in sand and potential opportunity for drag anchor design optimisation.]]></description>
      <pubDate>Wed, 11 Mar 2026 14:41:28 GMT</pubDate>
      <guid>https://trid.trb.org/View/2641252</guid>
    </item>
    <item>
      <title>Envelope of bearing capacity for gravity anchors in strain-softening soils under VHM loading: A Cosserat continuum FEM study</title>
      <link>https://trid.trb.org/View/2612148</link>
      <description><![CDATA[In offshore foundation bearing capacity analysis, the failure envelope method is widely used because it clearly separates load components. However, previous studies on the bearing capacity of gravity anchors under combined loads have not effectively accounted for soil strain-softening behavior. To address this limitation, a Mohr-Coulomb-matched Drucker-Prager model is adopted within the Cosserat continuum framework (MC-matched DP model). Numerical simulations were conducted using Abaqus’s user-defined element (UEL) functionality. Validation against existing literature confirms the accuracy and applicability of the Cosserat continuum model for analyzing the bearing capacity of gravity anchors under VHM combined loading conditions. This approach successfully resolves numerical convergence difficulties and pathological mesh dependency issues commonly observed in finite element analyses of strain-softening soils. The model was then applied to conduct a comprehensive analysis of the bearing capacity envelopes of gravity anchors. Through parametric studies, the influences of anchor embedment depth, vertical load magnitude, and strain-softening degree on the bearing capacity envelope were systematically investigated. Normalized bearing capacity envelope formulas were derived for various scenarios, providing a robust framework for evaluating the performance of gravity anchors under different conditions.]]></description>
      <pubDate>Mon, 02 Mar 2026 08:55:14 GMT</pubDate>
      <guid>https://trid.trb.org/View/2612148</guid>
    </item>
    <item>
      <title>Numerical study of three-dimensional pull-out capacity and structural optimization for dynamically installed anchors</title>
      <link>https://trid.trb.org/View/2630705</link>
      <description><![CDATA[Dynamically installed anchors (DIAs) are efficient, low-cost solutions for deepwater mooring systems, yet their performance under complex three-dimensional loading, particularly for inclined anchors and out-of-plane directions, remains a significant design challenge. This study employs validated 3D coupled Eulerian-Lagrangian modeling to systematically evaluate the pull-out capacity of DIAs, considering anchor inclinations (0°–30°), pull-out inclination angles (0°–90°), out-of-plane azimuthal angles (0°–180°), and various fin and padeye configurations. Results show that anchor performance is highly sensitive to loading direction: lateral bearing governs at pull-out directions close to horizontal, while frictional resistance dominates near vertical. Anchor inclination below 20° shows minimal influence on capacity, but greater inclinations cause notable capacity loss. Out-of-plane loading may increase capacity by up to 17 % for inclined anchors. Distinct normalized failure envelopes are established for each anchor inclination, remaining consistent across embedment depths and soil strength gradients, and allowing in-plane envelopes to conservatively represent out-of-plane scenarios for engineering design. Structural optimization demonstrates that increasing the fin width and elevating the fin position can enhance capacity by up to 27 %, while optimal padeye location can enhance capacity by as much as 60 %. A simplified estimation framework is proposed for rapid and practical anchor design.]]></description>
      <pubDate>Mon, 09 Feb 2026 16:18:11 GMT</pubDate>
      <guid>https://trid.trb.org/View/2630705</guid>
    </item>
    <item>
      <title>The sub-step iteration interface friction modelling method for numerical analysis of dynamically installed anchors</title>
      <link>https://trid.trb.org/View/2609007</link>
      <description><![CDATA[The Coupled Eulerian-Lagrangian (CEL) approach is the typical way used to study installation behavior of dynamically installed anchors (DIAs). However, there is still a lack of reasonable and reliable modelling of the anchor-soil interface friction variation behavior in soils with non-uniform shear strength in the existing literatures on DIA installation study. This work proposed a new interface friction modelling method named sub-steps iteration method (SIM) to consider the variation of the anchor-soil interface friction caused by the changing soil shear strength with penetration depths and the soil strain rate effect. The accuracy of dynamic penetration simulation based on SIM was verified by comparing the friction resistance and embedment depth to the centrifuge test data for a free-fall piezocone penetrometer. Parametric study was then conducted to investigate the effects of model mesh size, the number of sub-steps, and the iteration tolerance on the method accuracy. The performance of SIM was then further evaluated for three cases of torpedo anchors tested in field by comparing results from friction modelling using existing method. The results show that the SIM performs well in accuracy and computational efficiency. This study provides a more convenient and reliable interface friction simulation approach for the installation of DIA.]]></description>
      <pubDate>Fri, 05 Dec 2025 14:08:32 GMT</pubDate>
      <guid>https://trid.trb.org/View/2609007</guid>
    </item>
    <item>
      <title>Analytical and numerical investigation of gravity anchors for floating photovoltaic systems</title>
      <link>https://trid.trb.org/View/2594730</link>
      <description><![CDATA[Gravity anchors are a widely used anchoring solution for floating photovoltaic systems but can be costly and difficult to transport and install. To address this issue, 3D printed concrete gravity anchors can be fabricated offsite into a custom shape that optimizes the bearing resistance then filled with ballast onsite. This study evaluates the performance of gravity anchors with novel geometries enabled by 3D printing in representative sandy (drained) and clayey (undrained) soil layers for mooring angles ranging from 0 to 70°. The failure modes of gravity anchors were explored using numerical simulations with the goal of validating simpler analytical methods suitable for design. Results indicate that sliding primarily affects anchor efficiency (pullout capacity divided by buoyant weight) at small mooring angles, while overturning and plowing become dominant at larger mooring angles. Greater anchor efficiency is gained when using a skirt to enhance the passive bearing resistance, but difficulties may arise in the penetration of the skirt into sand. A C-shaped anchor with a padeye close to the center of gravity promoted plowing at high mooring angles. Analytical models are suitable fat lower mooring angles, but numerical simulations are recommended when evaluating anchor performance at mooring angles greater than 30°.]]></description>
      <pubDate>Wed, 24 Sep 2025 15:31:09 GMT</pubDate>
      <guid>https://trid.trb.org/View/2594730</guid>
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