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    <title>Transport Research International Documentation (TRID)</title>
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    <copyright>Copyright © 2026. National Academy of Sciences. All rights reserved.</copyright>
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    <managingEditor>tris-trb@nas.edu (Bill McLeod)</managingEditor>
    <webMaster>tris-trb@nas.edu (Bill McLeod)</webMaster>
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      <title>Influence of pipes and culverts on the performance of high speed railway embankments</title>
      <link>https://trid.trb.org/View/2534265</link>
      <description><![CDATA[A railway line needs to pass over necessary civil structures such as pipes, bridges and culverts. Because these structures are made of stiff materials such as concrete and steel, changes in track stiffness exist at the transition zone between the railway embankment and stiff structures. As a consequence, the dynamic stresses at backfills and interaction forces between the train body and the track are amplified at the transition zones. The field observation shows a rapid track degradation rate at the transition zones where frequent maintenance work has to be conducted. It is therefore an important subject receiving massive attention from academia and industry. The role of culverts in the dynamic performance of transition zones is studied aiming to better guidelines on transition zone performance. Numerical studies are conducted with a Finite Element Method using a commercial program Plaxis, and a linear elastic material model is used for transient dynamic analysis. The validation study has been performed by comparing the numerical and observation data regarding rail vertical displacements and their frequency content. The parameter study has been performed on culvert depth, culvert size, culvert shape and culvert foundation. Two different transition zone configurations are considered for deep and shallow culverts.]]></description>
      <pubDate>Fri, 04 Apr 2025 15:15:54 GMT</pubDate>
      <guid>https://trid.trb.org/View/2534265</guid>
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    <item>
      <title>Structural response analysis of concrete pavement</title>
      <link>https://trid.trb.org/View/2491236</link>
      <description><![CDATA[Cement concrete or concrete pavements are an integral part of the road network in many countries. In the United States, concrete pavements comprise approximately 45% of the road network. In comparison, the share in Sweden is almost negligible. In 2007, the Swedish Transport Administration (Trafikverket) initiated in close collaboration with the paving industry a field project with the aim of building knowledge and understanding on the structural response of concrete pavements. This report aims to characterize the structural response of a concrete pavement under varying traffic and environmental conditions. This is achieved by utilizing in-situ strains, stresses and deflections measured over an extended period of time from a concrete test slab. The structural responses and environmental conditions were measured using strain gauges, geophones, soil pressure cells and temperature measuring sensors. These instruments were installed at different locations of interest within the concrete slab. Loading was applied using dynamic falling weights and heavy trucks that travel at different speed levels. The strain measurements from the heavy truck were used to establish a relationship between applied axle load level and induced strain at various location of the slab.]]></description>
      <pubDate>Fri, 17 Jan 2025 15:16:58 GMT</pubDate>
      <guid>https://trid.trb.org/View/2491236</guid>
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      <title>Long-Term Monitoring of Post-Tensioning Tendon Force Using Optical Fiber Technology</title>
      <link>https://trid.trb.org/View/2449017</link>
      <description><![CDATA[Tendon forces are fundamental to the performance of post-tensioned (PT) bridges. Therefore, monitoring tendon forces is important for understanding the health of PT bridge elements and evaluating the condition of prestressing strands. However, there is currently no simple, reliable method for determining the tendon force that has been widely implemented. The ideal technology should provide a measurement of prestress (or strain) over the length of the tendon and not be limited to measurement only at discrete locations. When installed along the length of PT tendons, optical fiber sensors provide a promising means to overcome many of the challenges of tendon force measurement that currently exist. The technology offers the ability to assess the strain along the length of PT tendons as the bridge is in service. A specific optical fiber technology that allows strain to be assessed along PT tendons is Brillouin Optical Time Domain Reflectometry (BOTDR). Unlike optical fiber sensors that incorporate discrete fiber Bragg gratings, BOTDR can be used to measure strain along the entire length of the fiber. Moreover, the inclusion of optical fiber sensors along the length of the prestressing strands does not impact the structural performance of the tendon. The test program included in the research was aimed at assessing the accuracy and reliability of data acquired from the optical fiber sensors embedded in epoxy coating along the length of prestressing strands.  This document is a technical summary of the Purdue University report, Measurement of Post-Tensioning Tendon Force Using Optical Fiber Technology, available at https://rosap.ntl.bts.gov/view/dot/75679.]]></description>
      <pubDate>Wed, 27 Nov 2024 13:41:57 GMT</pubDate>
      <guid>https://trid.trb.org/View/2449017</guid>
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    <item>
      <title>A novel semi-analytical tool for stress interpretation using borehole breakouts</title>
      <link>https://trid.trb.org/View/2344794</link>
      <description><![CDATA[The present report describes a methodology developed within the frame of the BEFO project 408 for two applications. The first one concerns the prediction of the shape of borehole breakouts when the material properties and the in situ stress state is known. The second concerns the assessment of the in situ stress state when the material properties and the shape of the borehole breakouts is known. Both the possibility of being able to predict the stability of a borehole and the possibility of being able to assess the in situ stress state are relevant for a large number of applications. These include but are not limited to tunneling, including the smaller boreholes created for anchoring and blasting, the storage of nuclear waste, energy applications, such as gas production and hydrothermal energy and mining. The concept presented here is based on the method of conformal mapping. Conformal mapping is based on complex analysis and was initially applied to the solution of flow problems, most notable aerodynamics. In the field of civil engineering the method is most commonly used for the solution of groundwater flow problems with the approach of flow nets. In this report, the theory of conformal mapping, as well as the numerical methods used and their development, are presented in chapter 4 for the interested reader. With the possible exception of the sections referring to examples, reading this chapter is not necessary for most readers. The main results for the evaluation of the shape of the borehole breakouts are presented in chapters 5 and 6, while the main results for the evaluation of the in situ stress state are presented in chapter 7. Chapter 8 aims to provide an example for the application suggested here to real project data. The data used originate from the BRIE project, standing for Bentonite Rock Interaction Experiment and funded by SKB. For the needs of this project boreholes were cored in crystalline, granitic rock and subsequently bentonite parcels were installed. The whole construct was subsequently overcored for further testing and observation. Fracture mapping both before and after the introduction of bentonite is available, as well as estimates of the in situ stress state. Chapter 9 closes the report with conclusions, some observations and possible future extensions. The method that is presented here has been shown to agree well with experimental results and is significantly faster than the more precise but harder to calibrate and more cumbersome finite element simulations of the same problem. It is therefore hoped that it will provide a simple and easy to use tool for applications involving excavations in rock, with emphasis on the field of civil engineering and energy production.]]></description>
      <pubDate>Tue, 27 Feb 2024 14:25:55 GMT</pubDate>
      <guid>https://trid.trb.org/View/2344794</guid>
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    <item>
      <title>Railway wheel steel behaviour upon thermo-mechanical loadings</title>
      <link>https://trid.trb.org/View/2344762</link>
      <description><![CDATA[Optimised railway maintenance techniques such as rail grinding and milling, or rail repair welding, are vital to more sustainable rail networks. As demands on the railway increases, the need to better understand the material behaviour during local heating events occurring during maintenance is amplified. Other heating events can occur during operation, for instance during severe block braking. This thesis provides insight into thermal damage resulting from these local heating events on railway wheels, which can lead to altered mechanical properties and changed residual stresses. The material behaviour of the ferritic-pearlitic railway wheel steel ER7T was studied during severe block braking (i.e., slow heating and cooling) at peak temperatures varying between 300 °C and 650 °C. The thermal dilatation was restricted to different degrees between free expansion and full restriction. This study thus explores the combined effect of thermal and mechanical cycling on the mechanical properties and material structure. The experimental results from the thermo-mechanical testing were also used to validate a new constitutive material model for use in FE models to predict severe block braking. The second part of the thesis explored the effect of rapid heating and cooling events on the microstructure and residual stress state of railway wheel steel. Localised heating using laser scanning with additive manufacturing equipment was compared to the heating done by scanning with laser welding equipment. This study thus investigated the similarities of different rapid heating (high temperature) processes and the effect of process parameter variations. The results can be used to provide insight into the material behaviour of railway steels during local heating events. Furthermore, it can support the development of more accurate simulations for both operation and maintenance processes.]]></description>
      <pubDate>Tue, 27 Feb 2024 14:25:21 GMT</pubDate>
      <guid>https://trid.trb.org/View/2344762</guid>
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    <item>
      <title>Fatigue evaluation of ageing steel railway bridges on current rail network in Victoria</title>
      <link>https://trid.trb.org/View/2306851</link>
      <description><![CDATA[Although many of the existing railway bridges are structurally adequate to carry the increased rail loading, they still be expected to suffer from fatigue related to the cyclical application of modern freight axle loads. Rail authorities are paying attention to extend the service life of existing ageing railway bridges to manage a cost-effective solution for the rehabilitation. Most bridges in the Victorian railway networks are steel made and have been built during the late 19th to early 20th century, mostly still in service.  Increasing volume of traffic and axle weight of trains mean that current loads are much higher than envisaged from original design. In this context, issues as maintenance, assessment, rehabilitation and strengthening assume a significant importance. Fatigue life prediction of existing bridges is still a debated topic. Railway bridges may be exposed to high fatigue stress ranges and number of stress cycles that may lead to fatigue damage. AS5100.6 is based on traditional S-N curve method with fatigue parameters typically meant for the design of new bridges to achieve 100 years life. Constant amplitude stress range is assumed. However, when applied to assess the decades old bridges, it leads to conservatism that encourages a deficient structure demanding great economic impact. Due to the variability of past and present loadings, variable amplitude stress ranges are found to be more appropriate with fatigue damage calculated based on Palmgren-Miner Rule.]]></description>
      <pubDate>Thu, 07 Dec 2023 14:54:46 GMT</pubDate>
      <guid>https://trid.trb.org/View/2306851</guid>
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    <item>
      <title>BeFo 502 - Kopplad hydromekanisk modellanalys av bergspännings-, permeabilitets- och transmissivitetsförändringar under och efter tunnelutgrävningar i heterogena diskreta spricknätverk för kvantifiering av grundvattenläckage</title>
      <link>https://trid.trb.org/View/2269690</link>
      <description><![CDATA[Inflows into subsurface excavations generally occur through systems of fractures and deformation zones. Although the host rock formations may have very low permeability, fractures are the main pathways for water flow, which have a much greater permeability than the intact and undisturbed rock matrix. Fractures can also form and their hydraulic and mechanical properties can change during excavation, caused by deformations due to alterations in the stress field surrounding the excavation zone. This can in turn lead to unexpected flow behavior, such as increased inflows with great variability in seepage locations along a structure such as a tunnel, shaft or repository. Of particular concern are changes in the stress field caused by the excavation within the excavation damaged zone and the excavation disturbed zone (EDZ), which inevitably occurs regardless of excavation method. This project will study changes in the stress field due to excavation, within the excavation damaged and excavation disturbed zones, and how these alterations impact fracture aperture and permeability changes with subsequent effects on hydrogeological flows. Specifically, the focus is on stress changes cause by underground construction in a fractured rock environment using discrete fracture network (DFN) modelling methods. The DFN aspect is key, because inflows generally occur in highly localized points or transects in subsurface structures, corresponding to the intersections of fractures with the construction. Understanding the changes at the scale of fractures is therefore necessary to be able to make predictions at the larger system scale.]]></description>
      <pubDate>Mon, 16 Oct 2023 09:26:08 GMT</pubDate>
      <guid>https://trid.trb.org/View/2269690</guid>
    </item>
    <item>
      <title>Using of LWD in assessing the properties of fine grained subgrade soil with reference to M-E Pavement Design</title>
      <link>https://trid.trb.org/View/2075177</link>
      <description><![CDATA[The current project focuses on using the VTI’s multifunctional light weight deflectometer (LWD) to estimate the dynamic deformation moduli of fine-grained soil under repeated loading. The research focuses also on finding new relationships where results from repeated LWD tests can be used later in mechanistic-empirical pavement design.  The project is also aimed to verify the matching between the accumulated permanent strain of the tested soil measured by the in-situ repeated LWD and the accumulated permanent strain models adopted in mechanistic-empirical pavement design]]></description>
      <pubDate>Fri, 02 Dec 2022 11:40:29 GMT</pubDate>
      <guid>https://trid.trb.org/View/2075177</guid>
    </item>
    <item>
      <title>Restraint effects in portal frame bridges : practical design methodologies and background information</title>
      <link>https://trid.trb.org/View/1894897</link>
      <description><![CDATA[This report presents methodology, results and conclusions from the PhD-project “Evaluation, modeling and handling of restraint stresses in concrete bridges”, which can be relevant for bridge designers. The project investigated thermal actions in portal frame bridges, and the widths of cracks resulting from restraint effects. The main results and conclusions are given in the summary in Swedish, while the following parts in English presents both results and conclusions, as well as the methodology.The report is developed as a guide for practicing bridge designers on how the load case describing temperature differences between structural parts can be included in design. It also highlights the difficulties and need for further research on determining what the resulting crack widths are and how to design crack distribution reinforcement when cracking is caused by restraint effects.An extensive summary in Swedish is also part of the report.]]></description>
      <pubDate>Wed, 01 Dec 2021 14:46:10 GMT</pubDate>
      <guid>https://trid.trb.org/View/1894897</guid>
    </item>
    <item>
      <title>A Finite Element Approach to the Design of Flexible Pavements in Canada</title>
      <link>https://trid.trb.org/View/1754870</link>
      <description><![CDATA[The design of cost-effective, long-lasting pavements is of high importance in Canada, where daily and seasonal temperature varies significantly. Moreover, the abrupt changes in the global climate and its inverse impacts on transport infrastructures over the last decade require planning for necessary adaptations to mitigate those effects. More research should be conducted to address the potential impacts of climate change on the pavement design. A mechanistic analysis that considers thermomechanical loads could be a tool to study the possibility of variations in frequency or severity of pavement failure due to climate change. Such a model when is fed with site-specific material properties, traffic load, temperature profile, and pavement parameters, would more accurately predict the performance, serviceability and safety requirements. The pavement design may involve identifying tens of parameters, which makes it complex for pavement engineers.  The current study presents a finite element analysis of flexible pavements to evaluate thermal- and traffic-induced stresses for a selected highway cross-section in Canada. The original surface layer is asphalt concrete for which a linear viscoelastic behavior is assumed. Other layers of the flexible pavement were assumed elastic. The annual temperature profile of the studied construction site was obtained from the Long-Term Pavement Performance (LTPP) database. The change in layers stiffness due to air temperature was simulated by considering temperature-dependent material properties. The outcome of the finite element simulation was implemented into the Ontario pavement design guide to evaluate the design life of the studied cross-section. The outcome of this study was also compared with the AASHTO (1993) design procedure to investigate the similarities and discrepancies between the two methods.  The ultimate goal of this project is to develop an online, user-friendly interface to ease the implementation of the pavement design guide in Canada.]]></description>
      <pubDate>Tue, 01 Dec 2020 13:57:49 GMT</pubDate>
      <guid>https://trid.trb.org/View/1754870</guid>
    </item>
    <item>
      <title>BIG A2018-09 Tidsberoende effekter av schakt i lös lera</title>
      <link>https://trid.trb.org/View/1748848</link>
      <description><![CDATA[When soil is unloaded, time-delayed effective stress changes occur. In soils with low permeability such as clay, the changes can take considerable time. The subsequent effects on soil properties and forces acting on constructions are thus time-dependent. As a consequence of more efficient construction methods, an increased proportion of the stress changes will occur after the construction phase, as well as the magnitudes of unloading will increase due to deeper excavations. Existing methods of analyses are often based on simplified assumptions, combined with inadequate empirical knowledge, which poses a potential risk. The aim of the project is to increase knowledge about the effects of unloading of clays, focusing on time-dependency, in the context of deep excavations. It also aims to identify if measurement data differs from the expected values based on current calculation methods. The project is conducted as an industrial PhD project at Chalmers. The project until Lic exam can be summarized as: review of potential case studies, advanced laboratory testing, field measurements and analysis. The project results will strengthen geotechnical knowledge and facilitate function-oriented design of geotechnical works, especially design related to deep excavations and/or shorter construction times that the construction industry faces. Overall, the project is expected to contribute to optimized and safer design, reduced maintenance costs and predictable environmental impact.]]></description>
      <pubDate>Mon, 02 Nov 2020 14:08:52 GMT</pubDate>
      <guid>https://trid.trb.org/View/1748848</guid>
    </item>
    <item>
      <title>Mechanical test procedures for the evaluation of hydrogen-assisted damage in high-strength steel</title>
      <link>https://trid.trb.org/View/1667690</link>
      <description><![CDATA[Manufacturers in the automotive and aviation industries strive to implement advanced high-strength steel (AHSS) since components have to merge low mass with great strength. Due to the potential sensitivity of AHSS to hydrogen embrittlement (HE), it is very important that test methods be selected with a view to the application. This paper is based on the mechanical test methods for HE reported in scientific publications and may serve as a guide for the selection of appropriate test methods. The aggregation of sample geometries and testing procedures documented is aligned with the overriding issues regarding hydrogen susceptibility, formability, securement of manufacturing processes, and in-service conditions. (A)]]></description>
      <pubDate>Mon, 08 Jun 2020 17:36:53 GMT</pubDate>
      <guid>https://trid.trb.org/View/1667690</guid>
    </item>
    <item>
      <title>Effectiveness of a Multigrade-Type Binder in Recycling Recovered Asphalt Pavement (RAP)</title>
      <link>https://trid.trb.org/View/1657682</link>
      <description><![CDATA[Recycling old asphalt pavement has both environmental and economic benefits, but one question persists: “Does the old binder, coating the RAP aggregate, intermingle with the binder in the new mix or does the RAP behave like black rock?” Complete mixing of the old and the new binder is essential for effective rejuvenation of the old binder. A study using an engineered PG 52-40 binder with various amounts of recycled asphalt pavement (RAP) (15, 30 and 45%) in a drum mix plant was conducted at a recycling project in Cornwall, Ontario Binders from the RAP pile and from recycled hot-mixes containing various amounts of RAP were analyzed using SUPERPAVE MP1 binder characterization. Low temperature fracture properties of slabs sawn from the pavements were also tested by the thermal stress restrained specimen test (TSRST). Similar thermal cracking temperatures were obtained for both the binders and their respective pavement slabs tests, confirming that the binder in the new mix had commingled with the RAP binder. The RAP was not behaving as black rock. It verified also that the PG 52-40 multigrade-type binder, in rejuvenating the RAP, yielded hot mixes with binder properties similar to those in a brand new mix, even at high RAP contents.]]></description>
      <pubDate>Mon, 07 Oct 2019 14:54:30 GMT</pubDate>
      <guid>https://trid.trb.org/View/1657682</guid>
    </item>
    <item>
      <title>Development of energy-based damage and plasticity models for asphalt concrete mixtures</title>
      <link>https://trid.trb.org/View/1652290</link>
      <description><![CDATA[Characterizing the full range of damage and plastic behaviour of asphalt mixtures under varying strain-rates and stress states is a complex and challenging task. One reason for this is partly due to the strain rate and temperature dependent nature of the material as well as the variation in the properties of the constituent materials that make up the composite asphalt mixture. Existing stress-based models for asphalt concrete materials are developed based on mechanics principles, but these models are, however, limited in their application for actual pavement analysis and design since rate dependency parameters are needed in the constitutive model to account for the influence of the strain rate on the stress-based yield and evolution criteria. Till date, we are yet to arrive at simple and comprehensive constitutive models that can be used to model the behaviour of asphalt mixture over a wide range of strain-rate which is experienced in the actual pavement sections. The aim of this thesis is to develop an increased understanding of the strength and deformation mechanism of asphalt mixtures through multi-scale modeling and to develop simple and comprehensive continuum models to characterize the non-linear behaviour of the material under varying stress-states and conditions. An analysis framework is developed for the evaluation of the influence of asphalt mixture morphology on its mechanical properties and response using X-Ray CT and digital image processing techniques. The procedure developed in the analysis framework is then used to investigate the existence of an invariant critical energy threshold for meso-crack initiation which serves as the basis for the development of a theory for the development of energy-based damage and plastic deformation models for asphalt mixtures. A new energy-based viscoelastic damage model is developed and proposed based on continuum damage mechanics (CDM) and the thermodynamics of irreversible processes. A second order damage variable tensor is introduced to account for the distributed damage in the material in the different principal damage directions. In this way, the material response in tension and compression can be decoupled and the effects of both tension- and compression stress states on the material behaviour can be accounted for adequately. Based on the finding from the energy-based damage model, an equivalent micro-crack stress approach is developed and proposed for the damage and fracture characterization of asphalt mixtures. The effective micro-crack stress approach takes account of the material stiffness and a critical energy threshold for micro-crack initiation in the characterization of damage and fracture properties of the mixture. The effective micro-crack stress approach is developed based on fundamental mechanics principles and it reduces to the Griffith's energy balance criterion when purely elastic materials are considered without the need for the consideration of the surface energy and a crack size in the determination of the fracture stress. A new Continuum Plasticity Mechanics (CPM) model is developed within the framework of thermodynamics to describe the plastic behaviour of asphalt concrete material with energy-based criteria derived for the initiation and evolution of plastic deformation. An internal state variable termed the "plasticity variable" is introduced to described the distributed dislocation movement in the microstructure. The CPM model unifies aspects of existing elasto-plastic and visco-plastic theories in one theory and shows particular strength in the modeling of rate-dependent plastic behaviour of materials without the need for the consideration of rate dependency parameters in the constitutive relationships. The CPM model is further extended to consider the reduction in the stiffness properties with incremental loading and to develop a unified energy-based damage and plasticity model. The models are implemented in a Finite Element (FE) analysis program for the validation of the models.]]></description>
      <pubDate>Tue, 17 Sep 2019 10:32:35 GMT</pubDate>
      <guid>https://trid.trb.org/View/1652290</guid>
    </item>
    <item>
      <title>Unbonded Tendons as an Alternative for Bonded Tendons in Post-Tensioned Bridges: Constructability, Structural Performance, and Monitoring</title>
      <link>https://trid.trb.org/View/1556837</link>
      <description><![CDATA[Bonded post-tensioning tendons are used extensively in segmental bridge construction and have generally provided satisfactory service with respect to durability. However, multiple tendon failures in U.S. bridges with grouted tendons have led to the exploration of other forms of corrosion protection. One potential option is to use flexible fillers inside the tendon duct instead of cement grout that do not bond the prestressing strands to the concrete section. The use of these unbonded tendons not only affects the ultimate strength, fatigue, and serviceability behavior of structural systems, but also encourages efficient monitoring methods and facilitates tendon replacement during the structure’s service life. The current bridge design code, however, does not explicitly address flexible fillers, and little guidance is given regarding unbonded tendons in general. To evaluate the structural performance of unbonded tendons, full-scale experiments were conducted with both external and internal I-girder specimens having deviated tendon profile. These investigations provide important information on structural behavior of unbonded systems as well as tendon constructability, and can assist in the preparation of material and construction specifications. Multiple laboratory experiments were conducted with commercially available flexible fillers to examine the constructability of unbonded tendons. These experiments focused on tendon and duct detailing, filler material preparation, injection process and equipment, and venting procedures. An analytical investigation was also performed to compute the rate of cooling of flexible fillers during injection, which is a critical parameter to ensure that flow clogging does not occur. In addition, a promising tendon monitoring algorithm has been developed that uses the strain variations in the wedge plates caused by load relief due to corrosion-induced wire breaks. Extensive analytical and experimental investigations demonstrate the method’s feasibility in detecting, locating, and quantifying tendon damage.]]></description>
      <pubDate>Fri, 30 Nov 2018 17:04:22 GMT</pubDate>
      <guid>https://trid.trb.org/View/1556837</guid>
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