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    <title>Transport Research International Documentation (TRID)</title>
    <link>https://trid.trb.org/</link>
    <atom:link href="https://trid.trb.org/Record/RSS?s=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" rel="self" type="application/rss+xml" />
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    <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>Out-of-Plane Buckling Mechanism and Enhancing Method of Stiff Skeleton Arch Bridge When Wrapping Surrounding Concrete</title>
      <link>https://trid.trb.org/View/2643347</link>
      <description><![CDATA[This study investigates the stability of skeleton-reinforced concrete arch bridges during the concrete encasement process, employing a homogeneous generalized yield functions for extreme buckling load determination in nonlinear finite element analysis. Through an analysis of the stability of a stiff skeleton arch bridge with a 600 m span during the concrete wrapping stage, this study delves into and elucidates the mechanism by which the transverse brace enhances the out-of-plane stability capacity of the skeleton arch ribs. Additionally, a method for improving stability by controlling the lateral rotation angle of arch ribs is proposed. The results indicate that the lateral deflection angle of arch ribs serves as a crucial metric for assessing the out-of-plane stability of arch bridges. Transverse braces effectively coordinate and constrain the lateral deflections of two isolated arch ribs through their bending stiffness along the tangential direction of the arch axis. Notably, transverse braces within the range of L/8 to 3L/8 make the most substantial contribution to the lateral stiffness of arch ribs. Consequently, wrapping surrounding concrete on transverse braces within the L/8 to 3L/8 range proves advantageous for enhancing the stability of a stiff skeleton arch bridge under construction. Specifically, it is recommended to pour surrounding concrete on transverse braces at L/4 before the closure of the bottom plate’s concrete ring. After the ring of bottom plate’s concrete is closed, a symmetrical pouring of surrounding concrete on transverse braces from L/4 to the arch spring and vault is proposed.]]></description>
      <pubDate>Tue, 24 Feb 2026 09:01:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/2643347</guid>
    </item>
    <item>
      <title>Design Optimization of Temporary Cross Bracing for Long-Span Cable-Stayed Bridge Pylons Using the Minimum Bending Energy Method</title>
      <link>https://trid.trb.org/View/2622033</link>
      <description><![CDATA[The minimum bending energy method is currently used on cable towers of A-frame cable-stayed bridges constructed using the segmental method. In practical applications, the calculation results derived from this method serve merely as guidelines; the precise magnitude of the jacking force must be adjusted based on actual conditions. Furthermore, the applicability of this method to bridge towers employing alternative construction techniques or geometries warrants further investigation. The minimum bending energy method was introduced to determine and validate the jacking force of the temporary cross braces, while a self-developed Bridge Design and Construction Management System (BDCMS) program was used to conduct finite element analysis of the pylon in an ongoing long-span cable-stayed bridge project. Taking into account structural stress and pylon alignment, a comprehensive optimization strategy for the temporary cross braces was implemented. The results suggest that optimizing temporary cross braces using the minimum bending energy method is applicable, with the jacking force magnitude influenced by both the cross-brace position and the pylon’s inclination angle; under the optimized temporary cross-brace strategy, the stress difference following brace removal decreased from 6.2?MPa to 5.3?MPa, while the maximum stress difference after bridge completion was reduced from 5.7?MPa to 5.3?MPa. This ensures that the structural stress of the pylon during both the construction and operational stages complies with the specification requirements, providing valuable guidance for optimizing the temporary cross braces of A-frame pylons constructed in segments.]]></description>
      <pubDate>Thu, 13 Nov 2025 09:06:17 GMT</pubDate>
      <guid>https://trid.trb.org/View/2622033</guid>
    </item>
    <item>
      <title>How Lateral Bracing is Used for New and Rehabilitated Composite I-Girder Bridges across Europe and North America</title>
      <link>https://trid.trb.org/View/2553132</link>
      <description><![CDATA[Something as simple as the use of lateral bracing for a steel I-girder bridge should be consistent across the globe. However, an investigation into the bridge standards of different countries in Europe and North America revealed little to no consistency in how and why lateral bracing is specified or detailed. Most design codes recognize that adding lateral bracing—the diagonal bracing between the bottom flanges of a typical I-girder bridge superstructure—changes the load path of an I-girder bridge sufficiently to mimic the increased stiffness and fatigue life performance of a much more expensive steel box beam superstructure. Still, lateral bracing is rarely used or, if used, not accounted for in the structural capacity of the structure. This is often because the maximum benefit is found with superstructures with few deep girders in the cross section, and far less benefit is seen for shallower multi-girder cross sections. Additionally, accounting for the structural benefit of the lateral bracing increases the complexity of the bridge analysis model and precludes the use of simplified line-girder methods. For these reasons, the investigation showed that even when lateral bracing is used for reasons such as construction stability, it is rarely accounted for as a primary load carrying member in new structures. Since the inclusion of lateral bracing provides no structural benefit but also adds dead load and structural analysis complexity, most agencies attempt to eliminate lateral bracing from their structures and simply increase the capacity of the I-girders. However, for existing two-girder composite bridges, an approach is presented in which the careful addition of a new or structural consideration of existing bottom lateral bracing on an existing two I-girder superstructure could improve the live load distribution and reduce fatigue live load stress ranges sufficiently enough for the structure to remain in service without further structural strengthening.]]></description>
      <pubDate>Fri, 19 Sep 2025 08:58:23 GMT</pubDate>
      <guid>https://trid.trb.org/View/2553132</guid>
    </item>
    <item>
      <title>Rail freight transportation service network design with mixed blocking policies: Formulation and solution methods</title>
      <link>https://trid.trb.org/View/2476302</link>
      <description><![CDATA[In the current China railway system, the freight transportation service network is demand category oriented and is designed by using a hierarchical approach. This simplifies the design procedure, but reduces the flexibility and optimality of the plan. To make full use of the limited railway capacity and to improve the service flexibility and quality, this paper addresses the freight service network design problem with simultaneous consideration of mixed blocking policies and mixed service classes for heterogeneous demands. A mixed integer linear programming model is developed for the problem to maximize the operator's total transportation profit. Furthermore, a two-stage decomposition framework is proposed to solve the optimization model, where both exact and heuristic algorithms are employed. Extensive computational experiments on artificial and real-world instances indicate that the proposed solution approaches can generate high-quality solutions within reasonable time frame. Moreover, the mixed blocking policies could attract more freight demands and tend to result in higher profits, compared to the single blocking policy.]]></description>
      <pubDate>Mon, 27 Jan 2025 15:39:52 GMT</pubDate>
      <guid>https://trid.trb.org/View/2476302</guid>
    </item>
    <item>
      <title>Determining the Optimal Number of Stretch Film Layers for Ensuring Palletized Cargo Stability: A Simulation Study</title>
      <link>https://trid.trb.org/View/2487361</link>
      <description><![CDATA[Numerical simulation tests were carried out to determine the influence of the characteristic features of a load unit (such as: weight, height, number of load layers, coefficient of friction between the layers) per number of wraps with stretch film necessary to ensure unit stability. Manufacturers of stretch film sometimes provide guidelines on how many layers of film should be used depending on the weight and height of the load. But they do not explain on the basis of which studies these values were determined. Performing simulations similar to those made in this work in laboratory conditions would be very expensive. The work attempts to determine such relationships by simulation methods. A developed by the author in his earlier works dynamic model of a layered cargo unit wrapped with stretch film was used. The study plan was to check 108 cases. On the basis of the collected data, an attempt was made to develop a mathematical formula that would allow to estimate the optimal number of foil wraps when certain parameters of the load unit are known. In the author's opinion such an estimate could reduce film consumption, which would have a positive impact on the environment.]]></description>
      <pubDate>Mon, 13 Jan 2025 09:14:42 GMT</pubDate>
      <guid>https://trid.trb.org/View/2487361</guid>
    </item>
    <item>
      <title>Fixed Wave Screen Designs</title>
      <link>https://trid.trb.org/View/2217993</link>
      <description><![CDATA[Many sheltered harbors have been created through the reclamation of land or the construction of breakwaters and jetties. Due to increasing environmental concerns and regulations associated with filling bottom habitat, less intrusive wave screens are being developed to protect marinas from waves and currents. This paper describes two of these minimal-footprint wave screen structures, concentrating on the different design concepts used for various water depths and wave pressures and on the design features that are incorporated to facilitate their installations. The wave screens described in this paper are limited to fixed, not floating, structures. They typically consist of two major elements - pile supports and a wall or screen facing the currents or waves. The earliest and most basic wave screen structures were constructed of timber piles with timber bracing and screens. It is difficult to design these systems to resist significant wave pressures in moderate to deep water. With increasing water depths and harsher climates, steel piles are typically used and the screen itself may be constructed of a steel frame with timber or precast concrete panels. Two case studies are presented in this paper to illustrate innovative designs for shallow and deep water wave screens. The differences associated with resisting different wave pressures in different water depths are addressed, as well as the design features that are incorporated to facilitate fabrication and installation.]]></description>
      <pubDate>Mon, 16 Dec 2024 11:59:23 GMT</pubDate>
      <guid>https://trid.trb.org/View/2217993</guid>
    </item>
    <item>
      <title>Buckling Behavior of U-Shaped Girders</title>
      <link>https://trid.trb.org/View/2449428</link>
      <description><![CDATA[Trapezoidal box girder systems typically consist of twin steel U-shaped girders with a concrete deck acting compositely as the top flange. The top flanges of these U-girders are susceptible to lateral-torsional buckling during transport, erection, and placement of the deck. There is no existing codified design method for lateral bracing of U-shaped girders. Minimizing the amount of bracing used will lead to a more efficient design since this bracing makes up a significant amount of the total costs and is not utilized once the concrete deck has cured. In order to develop a design procedure for lateral bracing of U-girders, the behavior of unbraced U-shaped girders was first studied. An analytical program was undertaken to study the buckling behavior of unstiffened and transversely stiffened U-shaped girders using finite element models. A series of laboratory experiments were then performed using U-girder scale models in order to verify these analytical results. Finally, the analytical and experimental results were compared with existing design equations for torsionally braced I-shaped beams. The experiments verified that the fast buckling mode of these girders is an S-shape, not an Euler-type half and that transverse stiffeners can significantly increase the buckling capacity. It was also found that existing design formulas for torsional bracing are unconservative for these girders which have very small top flanges. New design equations must be developed. Test loads exceeded the theoretical predictions by as much as twenty percent which was attributed to the web corrugations (the web plate was not fabricated flat) in the welded girder.]]></description>
      <pubDate>Mon, 18 Nov 2024 17:16:32 GMT</pubDate>
      <guid>https://trid.trb.org/View/2449428</guid>
    </item>
    <item>
      <title>Use of Lean-On Cross-Frame Bracing in Steel Girder Bridges</title>
      <link>https://trid.trb.org/View/2209206</link>
      <description><![CDATA[Four steel bridges in Texas have been designed and will be constructed using lean-on bracing systems where individual cross-frames provide bracing to multiple girders. The detailing used in these bridges includes top and bottom lateral struts in girder bays adjacent to a cross-frame to allow several girders to lean on the cross-frame. Utilization of lean-on concepts should reduce fabrication costs since there will be fewer bracing members that need to be constructed, and also provide maintenance benefits over the life of the bridges since there will be fewer cross-frames to inspect. However, the most significant benefit from use of lean-on cross-frame concepts in bridges with skewed supports is that the bracing system can be laid out such that the cross-frames will pick up smaller forces under truck traffic in the completed bridge, than those that would occur with a conventional cross-frame layout. The bridge systems in which the lean-on bracing system is being implemented in Texas include three severely skewed bridges and one bridge with normal supports. This paper provides details of the specific system implemented in one of the skewed bridges.]]></description>
      <pubDate>Tue, 22 Oct 2024 15:57:24 GMT</pubDate>
      <guid>https://trid.trb.org/View/2209206</guid>
    </item>
    <item>
      <title>Experimental and Numerical Investigations About Hydraulic Top Bracings and Its Influence on Engine and Vessels Superstructure Vibrations</title>
      <link>https://trid.trb.org/View/1974288</link>
      <description><![CDATA[Top bracings are widely used to control vibration of main engines onboard ships. Currently two types of top bracings are used: hydraulic top bracings and mechanical top bracings with a friction connection. Main advantages of hydraulic top bracing are their improved ability to compensate relative deflections between the engine and the ship and that their dynamic characteristic can be controlled by different settings. Compared to conventional mechanical top bracings MAN-ES hydraulic top bracings have two basic settings that can be controlled by engine speed: the standard active setting and the passive setting. While in the active setting the hydraulic top bracing acts like a spring with a certain amount of stiffness, similar in its behavior to the mechanical type, in the passive setting it acts like a weak damper.To get more insight into the dynamic characteristics of hydraulic top bracings and their influence on the engine and structural vibrations, MAN-ES conducted several measurements on several ships. Based on the measurements, the working principle was, and their stiffness and damping properties were studied. Also, the condition with the top bracings being drained from oil and the correlation between the different top bracing settings and the vibrations response of the superstructure was investigated.In a joint project, DNVGL and MAN-ES aimed at correlating the measurement results by the simulation findings [1]. Based on a validated simulation model it was then even possible to investigate several more different nonstandard configurations and settings by additional simulations.]]></description>
      <pubDate>Fri, 23 Aug 2024 16:53:41 GMT</pubDate>
      <guid>https://trid.trb.org/View/1974288</guid>
    </item>
    <item>
      <title>Estimation of nosing load in existing railway transom top bridges based on field testing and finite element modelling</title>
      <link>https://trid.trb.org/View/2387053</link>
      <description><![CDATA[A significant number of wind bracings in existing railway transom top bridges are numerically assessed deficient against the assessment nosing load recommended by the AS5100, where in almost all cases, there is no observed evidence of wind bracings being overloaded. This paper estimates the nosing load applied by various trains to a couple of random spans of an existing railway transom top bridge. Firstly, field testing of this bridge is conducted and the measured stresses at the mid-center of girders and wind bracings are collected during various normal train operations to validate the developed Finite Element (FE) models of this bridge. Then, the nosing loads due to different trains are estimated using the validated FE model through a two-staged validation approach, including automatic FE stress intensity optimization and rigorous manual FE model sensitivity analysis while transoms in various conditions are also incorporated in the FE model. Results demonstrate that the nosing load is significantly less than the required load in the AS5100 with magnitudes ranging between 8.6% to 9.4% of the maximum vertical axle load of the passed trains; suggesting that the AS5100 assessment nosing load should be revised to avoid unnecessary expensive upgrades of numerically assessed deficient wind bracings.]]></description>
      <pubDate>Tue, 25 Jun 2024 10:31:58 GMT</pubDate>
      <guid>https://trid.trb.org/View/2387053</guid>
    </item>
    <item>
      <title>Field Measurements on Steel Girder Bridge with Skewed Supports Utilizing Lean-On Bracing</title>
      <link>https://trid.trb.org/View/2235655</link>
      <description><![CDATA[There are a number of performance stages that must be considered in bridge design. The critical stage for lateral torsional buckling of steel girder bridges often occurs during deck placement. The buckling capacity is improved by installing cross-frames at intemediate points along the bridge length. Many times, standard cross-frames are used, which can result in braces that are larger than required. These stiffer braces tend to attract larger live load forces and can lead to the development of fatigue cracks around the brace locations, particularly in bridges with skewed supports. Bridges with skewed supports are often necessary because of geometric constraints of underpasses or geological issues with the terrain. Though, a major concern with skewed bridges is differential deflection, which can intensify the propensity for fatigue cracks. Using lean-on bracing concepts can alleviate these concerns by allowing designers to reduce the number of cross-frames that are required as well as minimize live load induced forces in bridges for both skewed and non-skewed supports. The Texas Department of Transportation (TxDOT) recently implemented the recommendations of a research study on lean-on bracing [Wang 2002, Helwig and Wang. 2003] for three steel bridges with support skew angles of approximately 60 degrees. One of the bridges was instrumented with strain gages on the girders and braces prior to erection. The bridge performance was monitored during placement of the concrete bridge deck as well as subsequent live loading with two trucks loaded with sand. In addition to strains in the girders and braces, girder deflections and rotations were also monitored. This paper summarizes the results from the field monitoring and demonstrates the benefits of the lean-on bracing techniques.]]></description>
      <pubDate>Fri, 31 May 2024 13:57:41 GMT</pubDate>
      <guid>https://trid.trb.org/View/2235655</guid>
    </item>
    <item>
      <title>Compatibility Between Vehicle Seating Environments and Load Legs on Child Restraint Systems (CRS)</title>
      <link>https://trid.trb.org/View/2367263</link>
      <description><![CDATA[Load legs on child restraint systems (CRS) protect pediatric occupants by bracing the CRS against the floor of the vehicle. Load legs reduce forward motion and help manage the energy of the CRS during a crash. As more CRS manufacturers in the United States (US) consider incorporating these safety features into their products, benchmark data are needed to guide their design and usage. The objective of this study is to develop benchmark geometrical data from both CRS and vehicle environments to help manufacturers to incorporate compatible load legs into the US market.A sample of vehicle environments (n=104 seating positions from n=51 vehicles, model years 2015 to 2022) and CRS with load legs (n=10) were surveyed. Relevant measurements were taken from each sample set to compile benchmark datasets. Corresponding dimensions were compared to assess where incompatibilities might occur. Additionally, three CRS models with load legs were installed into 42 vehicle seating positions each (n=126 installations) to document physical incompatibilities.When comparing second row outboard seating positions to second row center seating positions, seat cushion angles were significantly steeper (14.5° vs. 12.7°, respectively, p=0.0299), seat cushion lengths were significantly longer (45.1 vs. 42.9 cm, respectively, p=0.0028), and the heights of the seat cushions were higher from the floor (37.4 vs. 29.3 cm, respectively, p<0.0001). Seat cushion heights from the floor did not appear to vary by vehicle size class, but sedans had significantly shorter seat cushion heights in the center position compared to other vehicle types (minivans, trucks, SUV/CUVs). Of the physical installations completed, n=4 in center positions had load legs which were too long to accommodate large drivetrain tunnels on the floor (i.e., the load leg could not be shortened far enough to allow a flush installation against the seat cushion). Interference occurred between the load leg and front center console in n=3 installations. Most load leg incompatibilities appear to occur in the second row center or third row seating positions.]]></description>
      <pubDate>Tue, 07 May 2024 09:44:36 GMT</pubDate>
      <guid>https://trid.trb.org/View/2367263</guid>
    </item>
    <item>
      <title>Fluid and Structural Analysis of the Safety and Reliability of the Communication Bridge</title>
      <link>https://trid.trb.org/View/2319345</link>
      <description><![CDATA[This paper presents the fragility analysis of the NPP Communication bridge support frame resistance due to extreme wind loads. The aim of the contribution is the reliability analysis of the structural bracing system of the bridge. The wind load was determined on base of the fluid analysis using ANSYS-FLUENT program. On the example of the steel bridge between two NPP buildings with the various forms of the bracing systems is considered the efficiency of the structural system. The beam and the link elements from ANSYS library were used. The methodology for proving capacity reserve of the structural resistance by non-linear analysis considering the uncertainty of the input parameters is described here. The advantages of the utilization the LHS method to analyze the safety and reliability of the structures is presented.]]></description>
      <pubDate>Thu, 18 Apr 2024 17:07:04 GMT</pubDate>
      <guid>https://trid.trb.org/View/2319345</guid>
    </item>
    <item>
      <title>Composite I-girder bridges with lateral bracing : Improved load distribution</title>
      <link>https://trid.trb.org/View/2344793</link>
      <description><![CDATA[This thesis deals with the subject of lateral bracing between the bottom flanges of I-girder composite bridges. The focus is on the impact of adding lateral bracing on existing bridges, as well as on new bridges. Experience and knowledge from bridge projects around the world are investigated and implemented in the evaluation of the research subject. Many existing bridges are in need of being strengthened or replaced, due to the increased traffic volume and heavier traffic loads. Different approaches can be used to prolong the lifetime of existing bridges. The approach is different depending on the cause, but for increasing the lifetime regarding fatigue some of the most suitable options are described in this thesis. A proposed concept is presented, in this thesis, along with some research questions to be answered. The use of lateral bracings in composite bridges varies between different parts of the world. In one country it can be a requirement/common praxis for long span composite bridges with two I-girders, in other countries there are no requirements of using them. Some parts of these regulations and requirements can be traced back to the tradition in both manufacturing and construction of this type of bridges. This thesis investigates how lateral bracing is used around the world to distribute eccentric loads between primary longitudinal structural members, provide resistance to lateral loads, and to permit an existing two-girder structural system to be retrofitted to behave similarly to an often more expensive closed steel box girder. Furthermore, several case studies have been conducted to investigate the impact on the structural behavior of composite bridges where a lateral bracing is implemented in the structure.]]></description>
      <pubDate>Tue, 27 Feb 2024 14:25:54 GMT</pubDate>
      <guid>https://trid.trb.org/View/2344793</guid>
    </item>
    <item>
      <title>Risk-based seismic design of diagonal self-centering shape-memory alloy wire-based bracing system in multi-column bent bridges</title>
      <link>https://trid.trb.org/View/2173942</link>
      <description><![CDATA[In this paper, a risk-based seismic design method for diagonal self-centering braces (SCB) with shape memory alloy (SMA) wires implemented in multi-column bents is proposed to enhance the performance of older concrete bridge classes. An existing SMA-SCB system that improves the performance of older reinforced concrete building frames was adopted to numerically examine further applications to nonductile bridges. To this end, risk-based seismic design of the SMA-SCB to minimize the probability of collapse and demolition of bridge classes was developed by adopting a sophisticated finite element model that reflects the recentering behavior of an actual SMA-SCB; probabilistic bridge models considering uncertainties associated with the material and geometrical properties of bridges; refined failure condition; and the total probability theorem. A comparison of the results of the traditional seismic fragility-based and proposed designs indicated that the amount of SMA-SCB required by the former is nearly half of that required by the proposed approach because the traditional approach overemphasizes the demand at larger ground motion intensities.]]></description>
      <pubDate>Wed, 28 Jun 2023 16:29:12 GMT</pubDate>
      <guid>https://trid.trb.org/View/2173942</guid>
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