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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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    <language>en-us</language>
    <copyright>Copyright © 2026. National Academy of Sciences. All rights reserved.</copyright>
    <docs>http://blogs.law.harvard.edu/tech/rss</docs>
    <managingEditor>tris-trb@nas.edu (Bill McLeod)</managingEditor>
    <webMaster>tris-trb@nas.edu (Bill McLeod)</webMaster>
    <image>
      <title>Transport Research International Documentation (TRID)</title>
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      <link>https://trid.trb.org/</link>
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    <item>
      <title>Use Of Fiber-Reinforced Polymer Composites for Bridge Repairs in Montana</title>
      <link>https://trid.trb.org/View/2684222</link>
      <description><![CDATA[Montana’s timber bridge inventory includes over 600 state and county owned bridges, many more than 80 years old and showing visible deterioration. Traditional girder repair methods, such as steel hangers and timber or steel sister girders, are heavy, labor-intensive, and often lack well-documented performance verification. Fiber-reinforced polymer (FRP) composites offer a light weight, corrosion-resistant alternative with strong potential for timber bridge rehabilitation, yet their application to timber bridges remains relatively underexplored, particularly at full scale and under field conditions. This report investigates the use of pultruded FRP composites to repair and strengthen deteriorated timber bridge girders to restore capacity and extend service life. Full-scale laboratory testing was conducted on 22 salvaged Douglas-fir/Larch beams from bridges across Montana. Beams were categorized as control, repaired (with pre-existing or induced splits and cracks), or strengthened (intact), and retrofitted using carbon–glass hybrid strips, glass FRP channels, or a combination of both. The channel–strip configuration showed the most robust performance, increasing moment capacity significantly compared to control specimens, while strip-only repairs also improved performance, particularly for moderately damaged beams. To validate the laboratory findings, selected FRP repair techniques were implemented on two in-service timber bridges near Toston, Montana. Installation was completed rapidly using standard tools, demonstrating the constructability of the repair systems under field conditions. A seven-month follow-up inspection indicated no visible deterioration or issues. Overall, this work provides a validated, field-tested approach for rehabilitating timber bridge girders using pultruded FRP composites, offering transportation agencies a practical strategy to extend the service life of aging timber infrastructure.]]></description>
      <pubDate>Fri, 27 Mar 2026 10:12:36 GMT</pubDate>
      <guid>https://trid.trb.org/View/2684222</guid>
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    <item>
      <title>Reliability Models for Plank Decks</title>
      <link>https://trid.trb.org/View/2235310</link>
      <description><![CDATA[In 1993 the American Association of State Highway and Transportation Officials (AASHTO) adopted a new load and resistance factor design (LRFD) code for highway bridges. The new code provides a rational basis for the design of steel and concrete structures. Although wood bridge design was also included in LRFD format, the calibration was not carried out for these structures. Therefore, there was a concern about the consistency of the reliability level for wood structures. Previous studies have shown that the reliability index for wood bridge components can be significantly different from those for steel or concrete structures. The degree of variation for wood properties is a function of dimensions, load duration, moisture content and other parameters. There is particular concern for plank decks, for which section aspect ratio also significantly affects results. The objective of this study is to summarize the load and resistance criteria for highway bridge plank decks, and to estimate the reliability of plank decks designed by AASHTO Code. A typical plank deck consists of planks placed on stringers that run either transversely to or parallel to the direction of traffic. The span length of stringers is usually 16–20 ft (5–6m), while stringers are typically spaced from 12–24 in (300–600mm). Stringers are commonly made of Southern Pine or Douglas-Fir sawn lumber, often nominally 6 in x 18 in (150 x 450mm), or larger. The planks are typically 4 in x 10 in (100 x 250mm) or 4 in x 12 in (100 x 300 mm).]]></description>
      <pubDate>Fri, 20 Mar 2026 08:38:25 GMT</pubDate>
      <guid>https://trid.trb.org/View/2235310</guid>
    </item>
    <item>
      <title>Evaluation of Alternative Materials for Timber Bridge Deck Plank Replacement</title>
      <link>https://trid.trb.org/View/2582877</link>
      <description><![CDATA[This project will focus on the evaluation of alternative materials for timber bridge deck planks to address the increasing costs, extended lead times, and maintenance challenges associated with the timber traditionally used by the Virginia Department of Transportation (VDOT). The study will include a literature and product review, experimental material and structural testing and a cost and feasibility analysis of alternative materials such as alternative timber species to what VDOT currently specifies, fiber-reinforced polymer composites, plastics, and isophthalic polyesters. Material testing will include mechanical, asphalt bonding, surface friction, and durability testing, while structural testing will include beam tests and connection tests on the alternative materials. The cost and feasibility analysis will consider aspects such as the material cost, expected lead times, ease of fabrication and installation, durability, and general ease of implementation. The projected outcome of this study will be recommended alternative materials for use in timber plank replacements. Implementation strategies will also be provided for incorporating these alternative materials into VDOT’s bridge maintenance practices.]]></description>
      <pubDate>Tue, 05 Aug 2025 10:04:19 GMT</pubDate>
      <guid>https://trid.trb.org/View/2582877</guid>
    </item>
    <item>
      <title>Quantification of Field Performance and Nondestructive Testing of Timber Bridges in Colorado</title>
      <link>https://trid.trb.org/View/2570257</link>
      <description><![CDATA[This report presents two major aspects related to evaluating timber bridges with nondestructive testing: i) laboratory experiments and ii) field applications. The first part of the report discusses the degradation processes and resulting outcomes of structural timber, Douglas Fir, that is broadly used for bridge construction. In accordance with the standard protocol of ASTM D1037, specimens are conditioned and their physical and mechanical properties are measured using nondestructive test methods: moisture metering, stress wave timing, and microdrilling. The second part of the report deals with the condition evaluation of timber bridges with the aim of synthesizing ratings from visual inspections (qualitative) and nondestructive testing (quantitative). Ten benchmark bridges, visually rated as Poor and Fair according to the scale of the Federal Highway Administration, are selected and their responses are examined by moisture metering, stress wave analysis, and microdrilling techniques for determining deterioration levels. A machine learning algorithm is trained and employed for comparative analysis, demonstrating that the integration of the two inspection approaches is achievable to improve the rating procedure for aged timber bridges. To implement Load and Resistance Factor Rating (LRFR), condition factors are calibrated and practice recommendations are suggested.  Implementation (Optional) Nondestructive testing is implemented for the condition rating of timber bridges.]]></description>
      <pubDate>Fri, 18 Jul 2025 09:05:44 GMT</pubDate>
      <guid>https://trid.trb.org/View/2570257</guid>
    </item>
    <item>
      <title>Structural damage identification using improved dynamic time warping fast algorithm based on largest triangle three buckets dimensionality reduction</title>
      <link>https://trid.trb.org/View/2521980</link>
      <description><![CDATA[This study proposes a structural damage identification approach through an improved dynamic time warping (DTW) fast algorithm based on the largest triangle three buckets (LTTB) dimensionality reduction, and further, a new damage-sensitive feature (DSF) is presented to study the similarity of the time series data from sensors in different conditions. In this paper, LTTB is used to reduce the dimension of structural vibration response time series data first. Then, the DTW values between sequences are calculated according to the sequence after dimensionality reduction, and the DSF values are further calculated. Finally, according to DTW values and DSF values, a comprehensive analysis is conducted to evaluate whether there is damage to the structure, the location and degree of damage, and the influence of environmental factors. The data from a wooden bridge structure and Z24 bridge is used to demonstrate the capability of the proposed algorithm in damage identification. The results indicate that the average identification accuracy of the wooden bridge is 98.44%, and the lateral sensors are more sensitive than the vertical sensors in detecting structural damage by the proposed algorithm; the average identification accuracy of the Z24 bridge is 98.83%, and the vertical sensors are more sensitive than the lateral sensors of the Z24 bridge by the proposed algorithm. In the two examples, the new DSF index is positively correlated with the damage degree of the structure. Compared with only using DTW, the dimensionality reduction based on DTW combined with LTTB can effectively improve the damage identification efficiency. The average time of calculating the DTW value of a wooden truss bridge decreases from 112.50 to 4.30 s. The average time to calculate a single DTW value of the Z24 bridge example decreased from 111.60 to 4.50 s. In both examples, the proposed algorithm can identify the structural damage, and the performance is not affected by environmental factors.]]></description>
      <pubDate>Tue, 22 Apr 2025 13:17:19 GMT</pubDate>
      <guid>https://trid.trb.org/View/2521980</guid>
    </item>
    <item>
      <title>Analysis of the service life of wooden bridge structures using structural protection</title>
      <link>https://trid.trb.org/View/2519696</link>
      <description><![CDATA[This article deals with the use of polyurea contact insulator as structural protection for wooden bridge structures. The waterproof coating is applied to a spruce wood substrate to create a composite element with a protective layer to protect the wood from atmospheric influences. The moisture conditions on the composite element are analyzed on the surface of the beam (under the insulator) and on the side surface. Furthermore, the adhesion of the investigated polyurea material to the beam is investigated by tear tests. The tear test shows that the cohesion between the studied composite materials is higher than the strength of wood perpendicular to the fibres. This experimental research confirms the suitability of using polyurea insulator on wood as a protective coating against atmospheric influences.]]></description>
      <pubDate>Thu, 27 Mar 2025 11:35:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/2519696</guid>
    </item>
    <item>
      <title>Nondestructive testing for condition evaluation of timber bridges: Synthesis of qualitative and quantitative methodologies by machine learning</title>
      <link>https://trid.trb.org/View/2496893</link>
      <description><![CDATA[This paper presents the condition evaluation of timber bridges with the aim of synthesizing ratings from visual inspections (qualitative) and nondestructive testing (quantitative). Ten benchmark bridges, visually rated as Poor and Fair according to the scale of the Federal Highway Administration, are selected and their responses are examined by sensor-based monitoring techniques, including moisture metering, stress wave analysis, and microdrilling techniques for determining deterioration levels. The moisture content of the bridges is also measured and a threshold value of 20 % is confirmed to be an acceptable limit that distinguishes Poor and Fair conditions. The degree of internal damage influences the velocity of stress waves travelling through the bridge girders, with a magnitude below 1362 m/sec indicating a Poor condition. On the changes observed in stress wave timing, the Fair-rated bridges exhibit a stable pattern relative to the Poor-rated bridges manifesting a 194.8 % higher coefficient of variation. When the bridge conditions decline, wave-timing values tend to rise above 734 microsec./m. The drilling resistance of the Poor-rated bridges is over 31 % lower than that of the Fair-rated bridges with a greater probability of being less than the baseline resistance of 70.7 %. As far as deterioration levels are concerned, there are discrepancies between the results of the qualitative and quantitative methodologies for the Poor-rated bridges; however, consistent observations are made for the Fair-rated bridges. A machine learning algorithm is trained and employed for comparative analysis, demonstrating that the integration of the two inspection approaches is achievable to improve the rating procedure for aged timber bridges. To implement Load and Resistance Factor Rating (LRFR), condition factors are calibrated and practice recommendations are suggested.]]></description>
      <pubDate>Fri, 07 Mar 2025 15:06:18 GMT</pubDate>
      <guid>https://trid.trb.org/View/2496893</guid>
    </item>
    <item>
      <title>Allowable stress rating compared to load and resistance factor rating for timber bridges with and without steel-beam retrofit</title>
      <link>https://trid.trb.org/View/2450936</link>
      <description><![CDATA[This paper presents the relevancy of the Allowable Stress Rating (ASR) and the Load and Resistance Factor Rating (LRFR) methods for timber bridges. Benchmark bridges constructed in the 1930′s are upgraded with hollow structural steel (HSS) beams and three-dimensional finite element models provide technical information that is necessary for examining their behavior and rating evaluations. Complying with published manuals, a total of 17 rating vehicles are considered across three categories (Design, Legal, and Permit) so as to generate the maximum responses of the bridges. The position of the vehicles dominates the deflection profiles of the unrepaired bridges. After installing the HSS beams, the live loads are redistributed and stiffness enhancement is noticed in the transverse direction of the bridges. The rating factors calculated with ASR exceed those with LRFR for the unrepaired bridges, regardless of vehicle configurations, and the level of disparity between these rating approaches increases when the bridges are repaired owing to differences in load factors. In terms of sensitivity to average daily truck traffic, the LRFR factors of the bridges under the Legal vehicles are more responsive than the factors subjected to other vehicle types. From a probability perspective, the compatibility of these rating methodologies varies contingent upon vehicle categories and the presence of the HSS beams. Practice guidelines are proposed to facilitate the conversion of rating factors between ASR and LRFR as a function of the present condition of constructed timber bridges.]]></description>
      <pubDate>Wed, 11 Dec 2024 10:39:04 GMT</pubDate>
      <guid>https://trid.trb.org/View/2450936</guid>
    </item>
    <item>
      <title>Transition of Allowable Stress Rating to Load and Resistance Factor Rating for Timber Bridges</title>
      <link>https://trid.trb.org/View/2441385</link>
      <description><![CDATA[This report presents the relevancy of the allowable stress rating (ASR) and the load and resistance factor rating (LRFR) methods for timber bridges. Benchmark bridges constructed in the 1930s have been upgraded with hollow structural steel (HSS) beams and three-dimensional finite element models provide technical information necessary for examining their behavior and rating evaluations. Complying with published manuals, 17 rating vehicles are considered across three categories (design, legal, and permit) to generate the maximum responses of the bridges. The vehicles’ position dominates the deflection profiles of the unrepaired bridges. After installing the HSS beams, the live loads are redistributed, and stiffness enhancement is noticed in the transverse direction of the bridges. The rating factors calculated with ASR exceed those with LRFR for the unrepaired bridges regardless of vehicle configurations, and the level of disparity between these rating approaches increases when the bridges are repaired owing to differences in load factors. In terms of sensitivity to average daily truck traffic, the LRFR factors of the bridges under the “legal” vehicles are more responsive than the factors subjected to other vehicle types. From a probability perspective, the compatibility of these rating methodologies varies contingent upon vehicle categories and the presence of the HSS beams. Practice guidelines are proposed to facilitate the conversion of rating factors between ASR and LRFR as a function of the present condition of constructed timber bridges.]]></description>
      <pubDate>Thu, 07 Nov 2024 14:55:21 GMT</pubDate>
      <guid>https://trid.trb.org/View/2441385</guid>
    </item>
    <item>
      <title>Minimizing Corrosive Action in Timber Bridges Treated with Waterborne Preservatives</title>
      <link>https://trid.trb.org/View/2209171</link>
      <description><![CDATA[Wood preservatives are required by AASHTO specifications in bridge applications to extend the service life of the wood members. The only exception is for naturally durable species, which are significantly more expensive. While the majority of wood used in bridge applications is treated with oil-type preservatives, wood treated with waterborne preservatives has been used in timber bridge applications. Many design engineers are choosing waterborne preservatives due to oil-type exudation concerns. As of January, 2004, the most common waterborne preservative of the past thirty years, Chromated Copper Arsenate (CCA), was voluntarily withdrawn from use in residential applications. While this withdrawal does not directly affect bridge applications, some designers are choosing to use alternative treatments to CCA, such as Alkaline Copper Quaternary (ACQ), Copper Azole (CuAz). It is believed that these preservatives are more corrosive towards metal than CCA because CCA contains hexavalent chromium and arsenic, both of which typically act as corrosion inhibitors, and are not contained in the CCA alternatives. In addition, these preservatives contain more copper than CCA, and the mechanism of corrosion of metals in contact with treated wood is believed to be related to the free copper within the wood. Unfortunately, there has been very little published research on the corrosiveness of wood treated with these preservatives because of the difficulties of measuring the corrosion rate in these environments. This work will briefly review published literature and current research activities on the corrosion of metals in contact with wood treated with waterborne alternatives to CCA. In addition, recommendations to minimize these corrosive effects in timber bridges will be discussed.]]></description>
      <pubDate>Tue, 22 Oct 2024 15:57:24 GMT</pubDate>
      <guid>https://trid.trb.org/View/2209171</guid>
    </item>
    <item>
      <title>Rehabilitation of Timber Railroad Bridges Using Glass Composite Fabrics</title>
      <link>https://trid.trb.org/View/2222196</link>
      <description><![CDATA[This paper presents a detailed outline pertaining to the rehabilitation of three timber railroad bridges located along the South Branch Valley Railroad (SBVR), in Moorefield, West Virginia. All three timber bridges were at least 50 years old, and acquired major renovations for adaptation to modern railroad traffic applications, i.e., 20 percent increase in load carrying capacity to accommodate the weight of a 315 kip locomotive. The refurbishment consisted primarily of piles, pile caps, and bridge stringers that were in an advanced state of decay. These sections were refurbished either in-situ or by temporary removal and prompt on-site renovation. The renovation consisted of: 1) Complete removal of loose/decayed material; 2) Existing cavity replenishment with consistent bulk adhesive; 3) Proper application of selected primer; 4) Suitable wrapping of resin-soaked fabric on piles, pile caps, and bridge stringers; and 5) Reinsertion of original bridge stringers after refurbishment with glass composite wraps. Load testing results from a portion of these initial bridges revealed that renovations accounted for relative stiffness values that are approximately double in comparison to the original substrates. The above renovation technique is non-intrusive, structurally sound, and economical proficient. Currently, an on-going monitoring program of the renovated bridge structures should provide us with a wealth of technical information, and establish the durability of the proposed renovation methodology.]]></description>
      <pubDate>Thu, 17 Oct 2024 15:24:26 GMT</pubDate>
      <guid>https://trid.trb.org/View/2222196</guid>
    </item>
    <item>
      <title>TRC2502: Development of Modern Methods for Evaluation of Timber  Pile Capacity</title>
      <link>https://trid.trb.org/View/2422926</link>
      <description><![CDATA[The Arkansas Department of Transportation (ARDOT) is responsible for inspecting and maintaining hundreds of timber pile bridges. Approximately 30% of these timber pile bridges are in poor condition, and the current ARDOT protocol for timber pile testing doesn't provide an actual pile capacity value that may be used to load-rate the structure. Although poor cross-sectional properties are identified from the measurement curve, the actual pile capacity is not determined. This research will utilize a combination of the IML PowerDrill and IML Fractometer II to determine timber pile capacity and define pile degradation curves, establishing equations for pile capacity based on pile characteristics and age. These thresholds will inform a system of determining pile quality, allowing ARDOT to implement measures to estimate the remaining service life of timber piles before they become structurally deficient and maintain an accurate database of bridges in need of replacement or rehabilitation or those that have failed. This research also aims to update current timber pile bridge inspection guidelines and develop a manual for determining pile capacity in the field.]]></description>
      <pubDate>Thu, 29 Aug 2024 12:29:12 GMT</pubDate>
      <guid>https://trid.trb.org/View/2422926</guid>
    </item>
    <item>
      <title>Experimental Investigation of the Repairability of a Cantilever Cross-Laminated Timber Diaphragm</title>
      <link>https://trid.trb.org/View/2409534</link>
      <description><![CDATA[Cross-laminated timber (CLT) has gained considerable interest in recent years as a low-carbon alternative to steel and concrete in construction. While CLT structures are designed to withstand extreme events, such as strong earthquake shaking, without collapsing, the aspect of postevent repairability is not explicitly addressed in current US design codes. This study thoroughly investigated the repairability of a previously tested 6.1×6.1  m (20×20  ft) cantilever CLT diaphragm that was damaged from reversed cyclic loading. Inspection and assessment of each of the components and connections indicated that the damage was localized to the connections (glulam-to-CLT screws and CLT-to-CLT surface splines), and the damaged diaphragm was deemed repairable. The repair strategy was intended to restore the capacity of the postrepaired diaphragm to the design strength of the initial undamaged diaphragm by replacing the damaged fasteners and surface splines with new connections. The repaired diaphragm was subsequently retested. The test results showed that the repaired diaphragm displayed slightly higher peak strength and comparable deformation capacity when compared to the initial diaphragm. This research underscores the potential viability of repairing damaged CLT diaphragms for performance restoration. However, further testing that encompasses other diaphragm configurations and varied fastener types may be needed to develop more comprehensive and effective repair strategies.]]></description>
      <pubDate>Mon, 05 Aug 2024 13:52:55 GMT</pubDate>
      <guid>https://trid.trb.org/View/2409534</guid>
    </item>
    <item>
      <title>Rehabilitating a Historic Wooden Covered Bridge to Carry Modern Truck Loads with No Visual Impacts to the Structure</title>
      <link>https://trid.trb.org/View/2234985</link>
      <description><![CDATA[In November of 2007, Pennoni Associates was awarded a historic wooden covered bridge rehabilitation project by a State Department of Transportation. Originally constructed in 1866, the historic covered bridge is listed on the National Register of Historic Places and spans 104'–6" over a state classified scenic river. The original scope of the project included removing and replacing deteriorated wood members as well as repairing the limited capacity steel superstructure that had been installed in 1977 as part of a bridge rehabilitation project. During preliminary design, the project scope was expanded to include replacing the existing superstructure with one that is capable of carrying current LRFD AASHTO live loads and providing a geotechnical analysis to identify abutment and subsurface design parameters. All the proposed project work required review by the State Department of Transportation as well as the State Historic and Museum Commission for authenticity compliance. The proposed work was not permitted to visually alter the appearance or historic character of the bridge. Currently the project is in the final design phase with construction anticipated for the spring of 2010.]]></description>
      <pubDate>Mon, 24 Jun 2024 09:31:45 GMT</pubDate>
      <guid>https://trid.trb.org/View/2234985</guid>
    </item>
    <item>
      <title>Rating of constructed timber bridges repaired with steel beams</title>
      <link>https://trid.trb.org/View/2330310</link>
      <description><![CDATA[This paper presents load ratings for timber bridges repaired with hollow steel sections (HSS) made of ASTM A500C. Two bridges are selected (F-22-V and H-20-T built in 1938 and 1935, respectively) and upgraded with HSS steel beams. A field test is conducted with a known-weight truck of 267 kN and responses are recorded. For numerical analysis, finite element models are formulated and validated. The model is then employed to investigate the behavior of the bridges under 17 live loads specified in the manual of a transportation agency. A mechanics-based rating approach is proposed to holistically rate these bridges before and after the repair. The configuration and position of the live loads affect the bending moment and shear force of the bridges; especially, the spacing of axles plays a role in increasing deflections. The capacity of the girders with the steel beams is as high as 2.56 times that of the control girders. Likewise, the allowable stress of the timber is improved by a factor of 1.39 and 2.09 for flexure and shear, respectively. The effectiveness of the repair becomes pronounced when the deterioration level of the timber girders rises, and the geometric properties of the steel beams are a crucial consideration that alters the rating of the repaired girders. The placement of grouped steel beams is recommended to raise the efficacy of the repair system. Owing to the repair, the failure probability of the bridges is reduced by up to 99.2%.]]></description>
      <pubDate>Wed, 27 Mar 2024 16:52:17 GMT</pubDate>
      <guid>https://trid.trb.org/View/2330310</guid>
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