<rss version="2.0" xmlns:atom="https://www.w3.org/2005/Atom">
  <channel>
    <title>Research in Progress (RIP)</title>
    <link>https://rip.trb.org/</link>
    <atom:link href="https://rip.trb.org/Record/RSS?s=PHNlYXJjaD48cGFyYW1zPjxwYXJhbSBuYW1lPSJzdWJqZWN0aWQiIHZhbHVlPSIxNzk2IiAvPjxwYXJhbSBuYW1lPSJkYXRlaW4iIHZhbHVlPSI3MzAiIC8+PHBhcmFtIG5hbWU9InN1YmplY3Rsb2dpYyIgdmFsdWU9Im9yIiAvPjxwYXJhbSBuYW1lPSJ0ZXJtc2xvZ2ljIiB2YWx1ZT0ib3IiIC8+PHBhcmFtIG5hbWU9ImxvY2F0aW9uIiB2YWx1ZT0iMTYiIC8+PC9wYXJhbXM+PGZpbHRlcnMgLz48cmFuZ2VzIC8+PHNvcnRzPjxzb3J0IGZpZWxkPSJwdWJsaXNoZWQiIG9yZGVyPSJkZXNjIiAvPjwvc29ydHM+PHBlcnNpc3RzPjxwZXJzaXN0IG5hbWU9InJhbmdldHlwZSIgdmFsdWU9InB1Ymxpc2hlZGRhdGUiIC8+PC9wZXJzaXN0cz48L3NlYXJjaD4=" rel="self" type="application/rss+xml" />
    <description></description>
    <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>Research in Progress (RIP)</title>
      <url>https://rip.trb.org/Images/PageHeader-wTitle-RIP.jpg</url>
      <link>https://rip.trb.org/</link>
    </image>
    <item>
      <title>Developing TxDOT Design Guidelines for Riprap Rock Size and Apron Limits at Culverts</title>
      <link>https://rip.trb.org/View/2768430</link>
      <description><![CDATA[Current design practices for bridge-class culverts often use bridge-centric or outlet-focused rip-rap rock size design equations, which do not adequately address inlet contraction scour, multiple culvert types, velocity amplification in wide structures, and varying soil erodibility. This project will develop defensible, culvert-specific rock sizing equations and apron design criteria tailored to varying culvert types (with-bottom and bottomless) and soil conditions. Researchers will: (1) perform literature review, survey, and site visits to synthesize design practice, identify research gaps, inspect Texas Department of Transportation's (TxDOT’s) data, and identify typical failure modes and vulnerable locations; (2) establish culvert-specific rock sizing equations for both with-bottom and bottomless culverts, with calibrated amplification factors for inlet and outlet culvert hydraulics and for both cohesive and non-cohesive soil conditions; (3) develop apron limits design criteria, including layout rules and quick-reference guidelines, that explicitly incorporate soil erodibility categories and address multiple vulnerable inlet and outlet transitions; and (4) produce ready-to-use design aids (charts, worksheets, and design examples), implementation recommendations, and quality assurance/quality control (QA/QC) checklists compatible with existing specifications and scour analysis procedures tailored for designers and maintenance personnel. These outcomes will provide TxDOT with scientifically robust design procedures compatible with the Specifications for the National Bridge Inventory (SNBI), enhancing infrastructure resilience and optimizing construction and maintenance expenditures.]]></description>
      <pubDate>Fri, 28 Aug 2026 10:02:11 GMT</pubDate>
      <guid>https://rip.trb.org/View/2768430</guid>
    </item>
    <item>
      <title>Bridge Approach Roadway Embankment Improvements</title>
      <link>https://rip.trb.org/View/2762034</link>
      <description><![CDATA[Bridge approach settlements, or bridge bumps, are a persistent challenge to Department of Transportations (DOTs), including Minnesota Department of Transportation (MnDOT), affecting ride quality, safety, and maintenance costs. These bumps result from differential settlement between the embankment and abutment, driven by soil settlement, erosion, inadequate drainage, poor compaction, freeze-thaw cycles, and traffic loads. 

MnDOT currently uses sandy backfills, and the cost of repairing settlements at the approaches are considerable. MnDOT is therefore exploring new ways of designing approach slabs. Possible mitigation methods include the use of Elasticized Expanded Polystyrene (EPS) foam as lightweight fill, Geosynthetic Stabilized Bridge Approaches (GSBA) developed by the Pennsylvania Department of Transportation (PennDOT), and cemented fills in embankments. The relative performance of these methods is unclear, and their suitability for Minnesota’s geotechnical and climatic conditions remains uncertain.


This research project will provide a comprehensive evaluation of these solutions for Minnesota bridges with the goal of reducing bridge approach bumps.]]></description>
      <pubDate>Tue, 18 Aug 2026 17:15:32 GMT</pubDate>
      <guid>https://rip.trb.org/View/2762034</guid>
    </item>
    <item>
      <title>Advancing Geotechnical Site Investigation with Automated 3D SPT-Seismic Testing</title>
      <link>https://rip.trb.org/View/2762014</link>
      <description><![CDATA[Effective geotechnical site characterization is essential for the planning, design, and long-term performance of transportation infrastructure. Unanticipated subsurface conditions (such as buried voids, weak soils, or highly variable stratigraphy) can lead to costly construction delays, change orders, and, in severe cases, structural distress or failure. For State DOTs responsible for delivering safe and resilient infrastructure, obtaining reliable information on subsurface conditions and their spatial variability is therefore critical during the early stages of project development.

Current practice relies heavily on invasive point-based methods such as Standard Penetration Test (SPT), Cone Penetration Test (CPT), and rock coring. While these methods provide high-quality measurements, they sample only a very small volume of material within individual boreholes. As a result, large portions of the subsurface remain uncharacterized, and critical features (such as voids, soft zones, or irregular bedrock surfaces) remain undetected between boreholes. Surface-based geophysical methods can provide broader spatial coverage; however, their resolution typically decreases rapidly with depth due to signal attenuation, limiting their effectiveness for deeper subsurface imaging.

Recent advancements in seismic testing have led to the development of the 3D SPT-seismic method, an innovative approach that integrates seismic wave analysis with conventional SPT operations to enable volumetric imaging around boreholes. The method records seismic waves generated by routine SPT hammer blows at depth using a 2D geophone array deployed at the ground surface. These waveforms are then analyzed using advanced 3D full-waveform inversion techniques to reconstruct a high-resolution three-dimensional shear-wave velocity (Vs) model surrounding the borehole. Field demonstrations at sites in Florida, Kansas, and Minnesota show that the method can produce subsurface images with approximately 2-ft spatial resolution across a large 3D domain extending up to 60 ft from the borehole at any tested depth (see additional document), with Vs profiles showing strong agreement with SPT-N values.

Despite its demonstrated potential, the current implementation still requires substantial manual data processing, limiting its routine use in practice. This project aims to advance the 3D SPT-seismic method by developing automated processing workflows and practical implementation guidelines that will enable state DOTs to efficiently generate high-resolution 3D subsurface images with routine SPT site investigations. The resulting capability will help reduce subsurface uncertainty, improve risk management, and support more informed design and construction decisions for transportation projects.

The primary objectives of this research are: (1) to automate the 3D SPT-seismic method and (2) to validate its applicability across a range of geological conditions commonly encountered by State DOTs to support widespread implementation. The project will focus on developing an integrated workflow that streamlines both data acquisition and analysis, enabling the method to be deployed efficiently alongside routine geotechnical investigations without disrupting standard SPT operations.

For automation, seismic signals generated by SPT hammer blows will be continuously recorded using a surface geophone array for all blows without interfering with the drilling crew. Advanced machine-learning algorithms will be implemented to automate key data-processing tasks, including signal conditioning, noise suppression, event detection, and removal of low-quality records. The processed data will be then analyzed via advanced 3D full-waveform inversion (FWI) to reconstruct a high-resolution 3D shear-wave velocity (Vs) image around the borehole, extending up to approximately 60 ft into the surrounding subsurface.

For validation, the methodology will be demonstrated through field testing at State DOT sites, with two test locations for each participating agency, representing a variety of soil and geological conditions. The results will be compared with SPT-N values to assess accuracy and practical benefits. By automating the analysis procedures and validating the method under real field conditions, this project will help transform the SPT-seismic approach into a practical and cost-effective tool for high-resolution geotechnical site characterization.]]></description>
      <pubDate>Tue, 18 Aug 2026 16:26:47 GMT</pubDate>
      <guid>https://rip.trb.org/View/2762014</guid>
    </item>
    <item>
      <title>Physics Informed Neural Network (PINN) enabled Predictive Resilience Framework for Maritime and Multimodal Levee Infrastructure</title>
      <link>https://rip.trb.org/View/2732360</link>
      <description><![CDATA[The performance and resilience of levee systems are governed by complex
hydro-mechanical interactions influenced by transient seepage, soil stratification, and environmental loading.
Conventional monitoring approaches, while effective in capturing field conditions, lack predictive capability and
often fail to integrate subsurface characterization with real-time system response. This study proposes a Physics-Informed Neural Network (PINN) enabled predictive resilience framework for maritime and multimodal levee
infrastructure, integrating multi-source sensing, geophysical imaging, and physics-based modeling. The
framework leverages Internet of Things (IoT) based sensor networks, including IMU derived tilt and displacement measurements, and
environmental variables such as rainfall, temperature, and soil moisture. To enhance subsurface characterization,
Electrical Resistivity Imaging (ERI) and Multichannel Analysis of Surface Waves (MASW) are incorporated to
capture spatial variability in moisture distribution, stiffness profiles, and potential seepage zones. These datasets
are fused with UAV based LiDAR point cloud models to develop high-resolution, temporal geospatial conditional
representations of levee geometry and deformation. The integrated dataset is utilized to calibrate finite element
method (FEM) based seepage and stability models, enabling accurate representation of coupled hydromechanical
behavior. The PINN architecture embeds governing equations of transient flow and unsaturated soil
mechanics into the learning process, allowing physically consistent prediction of pore pressure, volumetric
moisture content, and deformation fields. A hybrid physics-guided, data-driven digital twin will be developed to
continuously assimilate field and geophysical data, providing real-time predictions and identifying anomaly
thresholds indicative of instability. The proposed framework advances geotechnical asset management by
enabling predictive failure assessment, risk-informed decision-making, and proactive maintenance strategies,
thereby enhancing the resilience of critical maritime and multimodal infrastructure systems under extreme
environmental conditions.]]></description>
      <pubDate>Tue, 21 Jul 2026 16:41:56 GMT</pubDate>
      <guid>https://rip.trb.org/View/2732360</guid>
    </item>
    <item>
      <title>Improve MDOT's Understanding of the Acceptance and Performance of Riprap</title>
      <link>https://rip.trb.org/View/2731977</link>
      <description><![CDATA[The long term performance of riprap has been an issue because some local sources of riprap have known durability issues
and will degrade/dissolve over time. In addition, the acceptance of riprap size and gradation is currently done by performing a
Wolman count. Performing the Wolman count involves walking over large rocks, which can be a safety hazard and takes a
significant amount of time to do. There are challenges in assessing the performance and durability of riprap in riverine, lightly
acidic and other environments that need to be addressed. The potential exists that there may be technological and electronic
solutions that need to be utilized to enhance or replace existing processes.]]></description>
      <pubDate>Fri, 17 Jul 2026 15:21:06 GMT</pubDate>
      <guid>https://rip.trb.org/View/2731977</guid>
    </item>
    <item>
      <title>Enhanced Understanding of Geotechnical Processes</title>
      <link>https://rip.trb.org/View/2731975</link>
      <description><![CDATA[There is a need for a multidisciplinary hub for advancing geotechnical engineering practices in support of Michigan’s surface
transportation infrastructure. In alignment with the objectives outlined by the Michigan Department of Transportation (MDOT), the
Center will engage in a comprehensive suite of activities, including but not limited to education and workforce development, public
and stakeholder outreach, applied and theoretical research, implementation of innovative technologies, laboratory and field testing,
analytical modeling, and investigative services. These efforts will be guided by MDOT’s strategic priorities and may be further refined
through specific tasks detailed in this Scope of Services. The overarching goal of this center is to function as a responsive and
collaborative resource for MDOT by facilitating in the development, evaluation, and deployment of novel geotechnical solutions that
enhance the safety, durability, and sustainability of Michigan’s transportation systems. This can be done by fostering innovation and
continuous improvement in geotechnical engineering. The Center aims to bridge the gap between research and practice, ensuring
that emerging technologies and methodologies are effectively translated into real-world applications that benefit the traveling public
and support the long-term stewardship of the state’s infrastructure assets.]]></description>
      <pubDate>Fri, 17 Jul 2026 15:11:11 GMT</pubDate>
      <guid>https://rip.trb.org/View/2731975</guid>
    </item>
    <item>
      <title>Designing and Constructing Permanent Stable Foundation Layers in Areas of Sulfate Rich Soils</title>
      <link>https://rip.trb.org/View/2727387</link>
      <description><![CDATA[The presence of a suitable foundation layer plays a significant role in the constructability and long-term performance of pavements. During construction, these layers must provide sufficient support for placement and compaction of subsequent pavement layers, and during service life, these foundation layers play a critical role in the pavement structure by supporting the upper pavement layers and spreading loads to provide long-term pavement performance. When designed correctly, lime stabilized layers have a long history of providing permanent support in areas of plastic soils. However, lime has been removed from recent projects because of concerns over soluble sulfates. The use of select fill and geogrids has not provided projects with the support needed to successfully complete construction, and in some cases even handle construction traffic. These failures cost millions of dollars to fix and result in significant project delays. Adequate and permanent foundation layers are critical to performance of both flexible and rigid pavement structures. The research team will document the effectiveness of current practices for identifying sulfates on construction projects and determine if new or improved technologies exist to more effectively and reliably detect sulfates. The research team will deploy these tools on actual construction projects and document their effectiveness. Using advanced lab testing, the research team will determine treatment alternatives for soils containing sulfates. Based on the findings, the research team will recommend soil treatment or pavement structural design alternatives to provide permanent and stable foundation layers. The findings from this project shall be used to recommend updates to project selection, treatment guidelines, test procedures, specifications, and the Pavement Manual.]]></description>
      <pubDate>Fri, 10 Jul 2026 16:37:15 GMT</pubDate>
      <guid>https://rip.trb.org/View/2727387</guid>
    </item>
    <item>
      <title>Linking Landslide Triggering and Runout Hazard with Surface Deformations for Optimized Infrastructure Systems Resiliency</title>
      <link>https://rip.trb.org/View/2726550</link>
      <description><![CDATA[Landslides are one of the most significant geohazards impacting North Carolina's transportation network, causing fatalities, property loss, and long-term economic disruption. These events are frequently triggered by extreme precipitation from hurricanes and tropical storms, which have historically produced hundreds to thousands of debris during a single event. For example, Hurricane Helene (2024) triggered more than 2,000 reported landslides across the Southern Appalachians, resulting in widespread road closures, bridge damage, and tens of billions of dollars in direct and indirect losses. As the frequency and intensity of extreme precipitation events increase, the risk of cascading infrastructure failures is expected to grow. Current North Carolina Department of Transportation (NCDOT) Geotechnical Asset Management (GAM) tools primarily operate reactively— tracking known unstable sites and coordinating post-disaster repairs. Therefore, there is a critical need for proactive capabilities to anticipate landslide hazards before they disrupt the network.

The objective of this project is to create a robust, scalable, and computationally efficient framework to predict landslide triggering and runout at a regional scale, supporting optimized maintenance, emergency response, and risk-informed investment decisions. This work will integrate the North Carolina Geological Survey (NCGS) Post-Helene Landslide Inventory, surface deformation mapping, and AI enhanced triggering predictions. The research will pursue four main objectives: (1) consolidate and curate a high-quality georeferenced dataset of landslide and debris flow events in North Carolina; (2) develop machine-learning models informed by physics to predict triggering susceptibility based on rainfall thresholds, slope geometry, and hydrologic conditions; (3) link surface deformation signals to slope stability through finite-element-based surrogate models; and (4) compute landslide runout using depth-averaged Material Point Method (DA-MPM) simulations that account for three-dimensional topographic effects and infrastructure exposure.

The approach follows a hierarchical and computationally efficient workflow. Regional-scale data-driven models will rapidly screen the entire state for slopes with high triggering potential. For these critical sites, limit equilibrium analysis (LEA) using existing NCGS models will identify likely failure surfaces and factors of safety. The outputs will serve as inputs to physics-based DA-MPM simulations that predict debris flow runout, impact zones, and potential consequences for NCDOT-managed assets. This strategy maximizes coverage while focusing on high-fidelity simulations where they are most needed, thereby balancing predictive power with computational cost.

The anticipated products include trained machine-learning models, enhanced infinite-slope analysis incorporating AI training, a verified and validated DA-MPM module, and geographic information system (GIS)-integrated hazard/risk maps. Integration into NCDOT's existing GAM system will enable decision-makers to: (i) develop watchlists of critical slopes, (ii) anticipate maintenance and debris removal needs, (iii) coordinate detour planning and emergency response, and (iv) communicate risk more transparently to stakeholders. Training workshops will be held with NCDOT and NCGS engineers and geologists to ensure usability and gather feedback for future system enhancements.

This project represents the first step toward a real-time, data- and physics-informed landslide early warning and infrastructure risk management system. By combining machine learning, geotechnical modeling, and large-deformation simulation, this work will strengthen North Carolina's landslide risk assessment and improve transportation resiliency, reduce lifecycle maintenance costs, and protect the safety and mobility of the traveling public.]]></description>
      <pubDate>Thu, 09 Jul 2026 09:02:15 GMT</pubDate>
      <guid>https://rip.trb.org/View/2726550</guid>
    </item>
    <item>
      <title>Empirical Modeling for Improved Ground Failure Analysis</title>
      <link>https://rip.trb.org/View/2726232</link>
      <description><![CDATA[Problem Statement: Numerous bridge approaches and substructures, highway and railway embankments, and particularly roads in low-lying areas adjacent to rivers and their corresponding traffic sign and signal poles are underlain by the silt soils of the Willamette and Columbia River Valleys and below Oregon's coastal communities. These soils are susceptible to liquefaction or cyclic softening during earthquakes and will produce varying degrees of severity in the consequences such as lateral spreading displacement, global instability, and settlement. Settlement of soils will produce drag loads to bridge and traffic sign and signal pole foundations. Such damage has the potential to severely impact our critical surface transportation lifelines and reduce the efficacy of emergency responders and reduce the rate of economic recovery. The risk of seismic ground failure is exacerbated by groundwater table rise, which occurs during short-term, acute events (flooding) and the long-term effects of potential rising sea levels. Application of ground failure models to silty soils that were developed based on the responses of sandy soils can result in over-conservative estimates of the effects seismic ground failure and lead to inefficient use of limited resources as Oregon strives to maintain and improve its current resilience.
This work aims to develop the types of empirical relationships that the geotechnical community are well-familiar with but geared towards transitional silty soils, which can exhibit differing behaviors from the soils which are presently represented in available models. The objectives of this research are to produce specific design guidance, models, and spreadsheet-based tools to: (1) account for the effects of sloping ground on the calculation of the factor of safety against liquefaction/cyclic softening during earthquakes, (2) compute lateral displacements of sloping ground, and (3) calculate vertical settlements of level and sloping ground and any foundations buried within, to (4) culminate in a decision matrix for Oregon Department of Transportation (ODOT) engineers and their consultants to guide the selection of a particular model when assessing the seismic vulnerabilities of existing surface transportation infrastructure. The decision matrix and specific guidelines for conducting cyclic failure analyses and simplified displacement estimates will guide cost-effective measures to assess and improve existing surface transportation infrastructure and improve community and infrastructure resilience to increasingly combined natural hazards.
]]></description>
      <pubDate>Wed, 08 Jul 2026 17:38:31 GMT</pubDate>
      <guid>https://rip.trb.org/View/2726232</guid>
    </item>
    <item>
      <title>Subsurface Analysis Planning Tool for Cost Reduction, Rapid Emergency Evaluation, And Data Support for Rural Service Areas</title>
      <link>https://rip.trb.org/View/2726188</link>
      <description><![CDATA[Transportation professionals often make important decisions about system dependability, project design, and emergency response with limited time and data. This is particularly true as it relates to the underlying soil, rock, and groundwater conditions that directly affect the design and repair of critical infrastructure. Typically, designers and engineers rely on drilling boreholes and performing in-situ tests to characterize subsurface conditions and associated problems for applications ranging from bridges to roadways to stream crossings to landslides. Unfortunately, these exploration techniques are expensive, time-consuming, inherently risky, and often accompanied by significant lead times. Further, the complex nature of this data can be very difficult to interpret and the uncertainty difficult to quantify.

This research project will leverage investments from CLiP, Oregon Department of Transportation (ODOT) SPR786, and SPR808 to improve GOSEP algorithms for predicting subsurface information for planning and emergency response, with a focused aim for extrapolation improvement in rural, data sparse regions. This project also aims to expand the GOSEP database and thereby its capabilities by adding more geotechnical data and parameter datasets as well as by improving the OCR borehole log scanner for archived handwritten borehole logs.]]></description>
      <pubDate>Wed, 08 Jul 2026 17:34:58 GMT</pubDate>
      <guid>https://rip.trb.org/View/2726188</guid>
    </item>
    <item>
      <title>Phase 2: Leveraging Surface Monitoring to Guide Emergency Response and Long-Term Strategic Planning</title>
      <link>https://rip.trb.org/View/2725299</link>
      <description><![CDATA[Conventional monitoring, site investigation, and assessment of landslides for mitigation often requires drilling along with installation of piezometers and inclinometers which is not always feasible due to the significant expense of drilling, short lifespan of subsurface instruments, safety concerns about working on an active landslide, and difficult site access. A continued need exists to expand the capabilities of near-real-time surface monitoring of ground movements for (1) existing, monitored landslides to gather longer time-series of landslide response to variable wet seasons, and (2) newly-monitored landslides that reflect uncharacterized climatic and geologic conditions to extrapolate a spectrum of landslide impacts to Oregon Department of Transportation (ODOT) right-of-way, and (3) landslide events that occur and require quantitative information for decision-making. Such data is key for evaluating highway safety, repair and mitigation needs, and strategies for reopening after failure. The absence of this information places critical infrastructure and ultimately ODOT customers at risk.

The data from this expanded monitoring would inform important ODOT planning activities and research questions. For planning purposes, this data has already demonstrated benefits for emergency response to landslide events, planning around mitigation plans and Goal 18 discussions, maintenance considerations, and reduced ODOT time for inspection of landslides. Expanding these efforts would further support ODOT’s ability to monitor problematic slopes and make informed decisions regarding prioritization, planning, and sustaining mobility.]]></description>
      <pubDate>Wed, 08 Jul 2026 16:07:38 GMT</pubDate>
      <guid>https://rip.trb.org/View/2725299</guid>
    </item>
    <item>
      <title>Liquefaction Induced Lateral Spreading Loads On Bridge Pile Foundations</title>
      <link>https://rip.trb.org/View/2724825</link>
      <description><![CDATA[Earthquake induced soil liquefaction can result in significant displacements in sloping ground. This type of displacement is referred to as lateral spreading and is considered a substantial hazard to Oregon bridges. One current challenge facing bridge foundation design is the knowledge gap regarding appropriate selection of load factors for combining lateral spreading loads (kinematic) and superstructure inertial loads (inertia). Unfortunately, there is no consensus in design codes for how to combine inertial and kinematic loads. Failure to address this knowledge gap presents challenges for Oregon Department of Transportation (ODOT) engineers and designers. If lateral spreading and superstructure inertial loads interact during an earthquake, neglecting their combined effects could lead to inadequate and unsafe designs. Conversely, overconservatively combining these loads may result in costly, non-constructible foundations, particularly for piles passing through stiff, non-liquefiable crusts overlying deep liquefiable soils on sloped grounds. 

The primary objective of this research is to solidify ODOT’s design guidelines for combining superstructure inertial and lateral spreading loads in a pseudo-static analysis. The inertial and kinematic load interaction factors will be characterized by accounting for differences in seismicity in Eastern and Western Oregon, foundation types, and the complexity levels of design methods utilized in various ODOT projects. The proposed methodology for combining superstructure inertial and lateral spreading loads in a pseudo-static analysis will be detailed in a practice-ready recommended amendment to the ODOT Geotechnical Design Manual (GDM) and ODOT Bridge Design Manual (BDM).]]></description>
      <pubDate>Wed, 08 Jul 2026 14:50:18 GMT</pubDate>
      <guid>https://rip.trb.org/View/2724825</guid>
    </item>
    <item>
      <title>Phase III Wickiup Junction: Diatomaceous Soil Numerical Modeling to Support Design, Performance, and Feasibility</title>
      <link>https://rip.trb.org/View/2724820</link>
      <description><![CDATA[Diatomaceous soils exist at many Oregon Department of Transportation (ODOT) projects in Oregon, including the Wickiup Junction overpass site. Construction challenges have been encountered for ODOT projects on and in diatomaceous soils, including pile freeze, overlength piles, and excessive settlement. Ongoing Wickiup Junction embankment monitoring indicates that these embankments are undergoing continuous settlement at about 1.75 inches per year. Recently, a consultant’s feasibility study estimated that settlement mitigation for future overpass construction will cost $47M to $63M. This high mitigation cost is attributable to extensive deposits of soft and compressible diatomaceous soils that underlay the site. Considering that diatomaceous soils are non-standard geomaterials, limited literature, standards, or case histories exist to guide design and construction in these materials. However, this Wickiup Junction location may provide a prime translational research opportunity to improve engineering practice through development of a case history report with associated design charts for diatomaceous soils.

This highly applied research proposal will investigate the recently released design options at Wickiup Junction using advanced soil numerical modeling as a case study for design in diatomaceous material. This work will build on previous ODOT diatomaceous soil research to develop design tools that can be applied for construction in and on these deposits. Specific objectives include: (1) develop settlement model of the Wickiup Junction Overpass, and (2) develop design charts for diatomaceous soils.]]></description>
      <pubDate>Wed, 08 Jul 2026 13:53:05 GMT</pubDate>
      <guid>https://rip.trb.org/View/2724820</guid>
    </item>
    <item>
      <title>Overpredicted Resistances of Non-Displacement Piles in Sands Using Static Analysis Methods</title>
      <link>https://rip.trb.org/View/2720554</link>
      <description><![CDATA[he goal of this research is to determine the cause of the overpredicted resistances of the low-displacement piles in the project-specific subsurface conditions and either recommend modification factors that can be applied to the Nordlund method or recommend another static analysis method (such as the Beta or API method) to accurately estimate pile lengths. To achieve these goals, the existing data (where the resistance of low-displacement piles in sands was overpredicted) as well as data from two new projects (where the Minnesota Department of Transportation plans to drive low-displacement piles) will be systematically analyzed in this study. Regression methods and sensitivity analyses, as well as numerical simulations, will be used to better understand the reason for the overprediction of the pile resistance, and modify the existing static analysis models to improve the pile resistance predictions in sands. ]]></description>
      <pubDate>Tue, 30 Jun 2026 15:40:54 GMT</pubDate>
      <guid>https://rip.trb.org/View/2720554</guid>
    </item>
    <item>
      <title>Investigation of Using Higher Fines Backfill Materials in the Design and Construction of Mechanically Stabilized Earth Walls in Georgia
</title>
      <link>https://rip.trb.org/View/2719309</link>
      <description><![CDATA[The main objectives of this research project are: (1) examine the impact of gradation and fine content on the permeability, density, and shear strength of backfill materials, as well as soil-reinforcement interactions; (2) conduct a cost comparison analysis between Mechanically Stabilized Earth (MSE) wall design cases using higher fines backfill materials and current Georgia Department of Transportation (GDOT)-approved materials; and (3) perform Finite Element (FE) simulations to determine MSE wall deformation for various backfill materials.
]]></description>
      <pubDate>Thu, 25 Jun 2026 09:44:45 GMT</pubDate>
      <guid>https://rip.trb.org/View/2719309</guid>
    </item>
  </channel>
</rss>