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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>
    <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>
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      <title>Transport Research International Documentation (TRID)</title>
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      <title>Acoustic effect of sound absorbing materials and surfaces in road infrastructure</title>
      <link>https://trid.trb.org/View/2534204</link>
      <description><![CDATA[The most complex road infrastructures are often situated in urban areas which expose hundreds of thousands of people to harmful traffic noise levels. The geometrical complexity and the sound reflecting surfaces of these infrastructures affects the sound propagation. The noise calculation models, input data and evaluation methods may not be sufficient to correctly predict the noise levels spreading over the neighbourhoods. The aim of this Licentiate thesis was to investigate the acoustic effect of sound absorbing materials and surfaces in road infrastructure. This was done by changing the absorption indices, α, of existing sound reflecting noise barriers at real sites modelled in the Nord 2000 calculation model. The result showed that absorbers reduced the sound levels, but the effects were site dependent. Furthermore, some results of comparisons between measured and calculated sound levels require further studies, in relation to the question if it is necessary to complement the noise prediction method to be able to prove the acoustic effect of changing materials or installing absorbers. Since absorption data for direct sound field application (in-situ) were lacking for installed noise barriers and walls, they were obtained by sound Reflection Index, RIQ, measurements using the SOPRA method. This also led to the development of the Direct Field Absorption (DFA) model for evaluating RIQ measurements, which was tested with promising results.]]></description>
      <pubDate>Fri, 04 Apr 2025 15:14:52 GMT</pubDate>
      <guid>https://trid.trb.org/View/2534204</guid>
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    <item>
      <title>Development of a new recycled plastic noise wall specification</title>
      <link>https://trid.trb.org/View/2475151</link>
      <description><![CDATA[Major Roads Projects Victoria (MRPV), Ecologiq, Department of Transport Victoria (DoT), and the Australian Road Research Board (ARRB) have worked collaboratively on the development of a world first technical specific for plastic noise walls that allows the inclusion of up to 100% recycled content. The technical specification is based on noise wall suppliers achieving a series of performance-based requirements, as opposed to more traditional prescriptive based technical specifications. This will enable noise wall manufacturers to source material from various supply lines and encourage varying design solutions. The performance-based requirements cover a range of key criteria including acoustic performance, UV stability, impact resistance and graffiti resistance. Typically, each requirement defines the performance that is required to be achieved and the test or measure used to determine conformance.  The advantages of using recycled plastic noise walls over other more traditional materials (including concrete, timber and steel) include the panels being lighter and safer to install and maintain, they can be manufactured in any colour or pattern, better acoustic performance due to the void created within the panel, and most importantly, the use of recycled postconsumer plastics.  The new plastic noise wall technical specification has successfully been trialled on the Mordialloc Freeway in Melbourne's southeast. The project includes 11.7 km of noise walls that have a 75 % recycled content, which is estimated to be equivalent to 30 million plastic bottles or waste from 25,000 homes in one year.]]></description>
      <pubDate>Mon, 09 Dec 2024 19:05:28 GMT</pubDate>
      <guid>https://trid.trb.org/View/2475151</guid>
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      <title>Characterization of train-induced aerodynamic loads on high-speed railway vertical noise barriers</title>
      <link>https://trid.trb.org/View/2389026</link>
      <description><![CDATA[High-Speed Railway (HSR) technology requires the deployment of noise barriers to mitigate noise pollution affecting nearby residents. As train speeds increase, so does the magnitude of aerodynamic effects such as aerodynamic noise and the pressure on these barriers, meaning that these structures require robust sound insulation and structural load-bearing capacities. Train-induced aerodynamic loads must therefore be accounted for in the structural design of HSR noise barriers, and accurate characterization of these loads is vital for ensuring noise barrier performance and safety. Current European standards primarily evaluate aerodynamic loads on noise barriers based on train speed and the distance to the track centre. However, geometric differences between high-speed trains (HSTs) from different countries and regions necessitate the validation and potential revision of existing load calculation models. This thesis aims to enhance the characterization of train-induced aerodynamic pressure on HSR noise barriers and develop more accurate models for its calculation, focusing on the most common barrier type—vertical noise barriers. Initially, a thorough literature review was conducted to assimilate current knowledge on this topic and pinpoint existing gaps and challenges. Multiple factors including the geometric properties of trains and the heights of noise barriers were then analysed using computational fluid dynamics (CFD) simulations to evaluate their impact on the train-induced aerodynamic pressure on vertical noise barriers. Finally, the suitability of existing pressure calculation models was evaluated using literature data and a modified calculation model building on the EN 14067-4 model was developed.]]></description>
      <pubDate>Mon, 10 Jun 2024 14:05:34 GMT</pubDate>
      <guid>https://trid.trb.org/View/2389026</guid>
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    <item>
      <title>Noise wall design guideline: design guideline to improve the appearance of noise walls in NSW</title>
      <link>https://trid.trb.org/View/2289110</link>
      <description><![CDATA[This updated guideline, published as part of the Beyond the Pavement initiative, addresses the issue of noise wall design and its effect on the community, customers and landscape of NSW. Noise walls are probably the most widely recognised form of noise mitigation. They are particularly useful and effective in urban areas and where space is limited. This document sets down objectives, principles and detailed guidelines that will lead to well designed and cost-effective noise walls. It encourages a design approach that is considerate of the character of the transport corridor, its context and the views to and from it and the interests of the community and travellers. It stresses the importance of maintenance and the need for simple, robust designs. Above all, it leads to a balanced approach to design so that noise walls are not just utilitarian noise reduction measures but also fit sensitively into their context and are attractive elements in their own right.]]></description>
      <pubDate>Thu, 09 Nov 2023 15:56:41 GMT</pubDate>
      <guid>https://trid.trb.org/View/2289110</guid>
    </item>
    <item>
      <title>Hohe Lärmschutzwände auf Brücken. Lösungsmöglichkeiten der Lastabtragung der
Verankerung, der Bemessung und der Ermüdung</title>
      <link>https://trid.trb.org/View/2237071</link>
      <description><![CDATA[Standardlösungen für Lärmschutzwände (LSW) auf Brücken bis 5 m Gesamthöhe können oft - auch in Kombination mit lärmmindernden Fahrbahnbelägen - die Anforderungen an den Lärmschutz nicht erfüllen. Daher werden vermehrt LSW mit einer Höhe von über 5 m eingesetzt. Dafür sind jeweils individuelle Nachweise zu führen, mit der Folge vieler unterschiedlicher Lösungen. Darüber hinaus können die konstruktive Durchbildung des Anschlusses auf dem Bauwerk sowie der lastweiterleitenden Bauteile mit zunehmender Höhe maßgeblichen Einfluss auf den Entwurf haben. Insbesondere ermüdungswirksame Beanspruchungen aus Wind können für die Bemessung der Verankerungselemente relevant sein. Die dynamischen Beanspruchungen sind daher zu quantifizieren und die Ermüdungssicherheit ist nachzuweisen. Ziel ist es, bundeseinheitliche, technisch und wirtschaftlich ausgereifte Lösungen zu erarbeiten, die neben den Grenzzuständen der Tragfähigkeit und Gebrauchstauglichkeit auch die mit hohen Wänden steigenden Ermüdungsbeanspruchungen vorrangig in den Befestigungselementen berücksichtigen. Das Tragverhalten hoher senkrechter LSW bis 9 m ist hinsichtlich der Anforderungen an die Verankerungselemente sowie an die lastweiterleitenden Elemente in den Überbau zu untersuchen. Neue Erkenntnisse über statische und dynamische Parameter für hohe LSW auf Brücken sollen gewonnen und prüffähige Lösungen zur konstruktiven Durchbildung sollen im Hinblick auf einheitliche Vorgaben für eine wirtschaftliche und ermüdungsgerechte Ausführung hoher LSW und deren Verankerung auf Brücken verfügbar gemacht werden, beispielsweise für Regelwerke. ABSTRACT IN ENGLISH: Standard solutions for noise barriers on bridges up to 5 m total height often cannot fulfil the noise protection requirements, even in combination with noise-reducing road surfaces. Therefore, noise barriers with a height of more than 5 m are increasingly used. For these noise barriers, individual verifications have to be carried out, resulting in many different solutions. In addition, the structural design of the connection on the structure as well as the load-transmitting components can have a decisive influence on the design with increasing height. In particular, fatigue loads from wind can be relevant for the design of the anchoring elements. The dynamic stresses must therefore be quantified and the fatigue safety must be verified. The aim is to develop nationally uniform, technically and economically mature solutions that, in addition to the ultimate and serviceability limit states, also take into account the fatigue stresses that increase with high noise barriers, primarily in the anchoring elements. The load-bearing behaviour of high vertical noise barriers up to 9 m is to be investigated with regard to the requirements on the anchoring elements as well as on the load-transmitting elements in the superstructure. New knowledge about static and dynamic parameters for high noise barriers on bridges should be gained and testable solutions for the structural design should be made available with regard to uniform specifications for an economic and fatigue-appropriate design of high noise barriers and their anchoring on bridges, for example for codes of practice.]]></description>
      <pubDate>Mon, 18 Sep 2023 11:48:42 GMT</pubDate>
      <guid>https://trid.trb.org/View/2237071</guid>
    </item>
    <item>
      <title>Ursachenforschung zu Schäden an Lärmschutzwänden mit Vorsatzschale aus Porenbeton</title>
      <link>https://trid.trb.org/View/1928874</link>
      <description><![CDATA[Lärmschutzwände aus Beton, die aus einer Vorsatzschale aus haufwerksporigem Leichtbeton (Absorptionsschale) im monolithischen Verbund mit einer gefügedichten Stahlbetontragschale bestehen, werden häufig an Bundesfernstraßen verbaut. Bisher waren diese Lärmschutzwände von einer langen Dauerhaftigkeit geprägt. In jüngerer Vergangenheit sind jedoch Schäden bekanntgeworden, bei denen sich die Vorsatzschale vom Tragbeton nach zum Teil wenigen Jahren Nutzung schalenartig und großflächig gelöst hatten und herabfielen. Ziel dieses Forschungsprojektes ist es, die Ursachen der Ablösung dieser Vorsatzschale von der Stahlbetontragschale durch systematische Untersuchungen zu ermitteln und geeignete Abhilfemaßnahmen bei Materialwahl, Herstellung und Einbau derartiger Wandelemente zu erarbeiten. Damit soll der Neubau solcher Lärmschutzwände wieder schadensfrei möglich sein und die Instandsetzung bereits geschädigter Lärmschutzwände technisch und wirtschaftlich erfolgreich sein. (A) ABSTRACT IN ENGLISH: Noise protection walls made of concrete, which consist of a facing layer of no fines lightweight concrete (absorption layer) in a monolithic bond with a structurally sealed reinforced concrete supporting layer, are often installed on federal trunk roads. So far, these noise barriers have been characterized by a long durability. In the recent past, however, damage has become known in which the facing shell had detached from the supporting concrete after a few years of use, in some cases in the form of shells and over large areas, and had fallen down. The aim of this research project is to determine the causes of the detachment of this absorption layer from the reinforced concrete load-bearing layer through systematic investigations and to develop suitable remedial measures for the choice of materials, manufacture and installation of such wall elements. In this way, the new construction of such noise barriers should again be possible without damage and the repair of already damaged noise barriers should be technically and economically successful. (A)]]></description>
      <pubDate>Fri, 18 Mar 2022 04:37:25 GMT</pubDate>
      <guid>https://trid.trb.org/View/1928874</guid>
    </item>
    <item>
      <title>Experimental and numerical study on structural behaviour of tyre-bale sandwich wall under different loading conditions</title>
      <link>https://trid.trb.org/View/1925752</link>
      <description><![CDATA[]]></description>
      <pubDate>Thu, 10 Mar 2022 08:33:05 GMT</pubDate>
      <guid>https://trid.trb.org/View/1925752</guid>
    </item>
    <item>
      <title>Experimental study on flexural behavior of new type of prestressed reactive powder concrete sound barrier for high-speed rail</title>
      <link>https://trid.trb.org/View/1909590</link>
      <description><![CDATA[]]></description>
      <pubDate>Mon, 07 Feb 2022 14:17:53 GMT</pubDate>
      <guid>https://trid.trb.org/View/1909590</guid>
    </item>
    <item>
      <title>SOPRANOISE</title>
      <link>https://trid.trb.org/View/1873025</link>
      <description><![CDATA[Die Durchführung der in-situ-Prüfungen der Luftschalldämmung und Reflexion von Lärmschutzwänden (DIN EN 1793-5 und DIN EN 1793-6) ist messtechnisch anspruchsvoll und zeitintensiv. Daher sind die Methoden nur für stichprobenartige Überprüfungen praktikabel. Schnelle Messprozeduren zur Abnahme neuer Lärmschutzwände oder zur Prüfung beschädigter Lärmschutzwände sind wünschenswert. Das Projekt SOPRANOISE (Securing and Optimizing the Performance of Road trAffic NB with New methOds and In-Situ Evaluation) adressiert neue Werkzeuge zur Bewertung der akustischen Wirksamkeit von Lärmschutzwänden. Das primäre Ziel ist die Entwicklung einer innovativen, schnellen und sicheren Methode zur einfachen in-situ-Charakterisierung installierter Lärmschutzwände. Hierzu soll eine strukturierte Handlungsempfehlung aufgestellt werden. (A) ABSTRACT IN ENGLISH: The performance of in-situ tests of airborne sound insulation and reflection of noise barriers (DIN EN 1793-5 and DIN EN 1793-6) is metrologically demanding and time-consuming. Therefore, the methods are only practicable for random checks. Fast measurement procedures for the acceptance of new noise barriers or for testing damaged noise barriers are desirable. The SOPRANOISE project (Securing and Optimising the Performance of Road trAffic NB with New methOds and In-Situ Evaluation) addresses new tools for evaluating the acoustic effectiveness of noise barriers. The primary objective is to develop an innovative, fast and safe method for easy in-situ characterisation of installed noise barriers. For this purpose, a structured recommendation for an inspection procedure is to be established. (A)]]></description>
      <pubDate>Tue, 26 Oct 2021 10:04:04 GMT</pubDate>
      <guid>https://trid.trb.org/View/1873025</guid>
    </item>
    <item>
      <title>the BRRC and AWV are jointly testing low-screen diffractors along the N445 in Zele</title>
      <link>https://trid.trb.org/View/1764178</link>
      <description><![CDATA[Diffractors are a recent invention that can help reduce traffic noise exposure from homes in the vicinity of arterial roads. They consist of a series of narrow slots of varying depth placed parallel to the axis of the road. Traffic noise propagating along the ground and passing across the diffractor towards nearby houses makes the air in the slots vibrate as if they were long, flat organ pipes. The different slots vibrate at different wavelengths and merge in turn form secondary sound sources, the sound of which deflects the passing traffic noise upwards. This results in a reduction in traffic noise exposure at the level of the houses. At the request of AWV, in the summer of 2019, a 140 m long, temporary arrangement was placed along the N445 in Zele, which has been provided with a recent road surface in diced concrete slabs. The set-up consisted of 1.05 m wide diffractors placed on a 1.10 m high screen (figure 2). The intention was to measure at greater distances and at different measurement heights to determine whether this measure could be useful on regional roads with 2x1 lane and houses in the immediate vicinity.]]></description>
      <pubDate>Thu, 21 Jan 2021 13:35:14 GMT</pubDate>
      <guid>https://trid.trb.org/View/1764178</guid>
    </item>
    <item>
      <title>Evaluation of Modified H-Piles Subject to Lateral Loading for Sound Wall Applications</title>
      <link>https://trid.trb.org/View/1754889</link>
      <description><![CDATA[Sound walls are utilized for mitigating ambient noise caused by traffic or industrial and commercial activities. Sound wall foundations are typically subject to large lateral load and bending moment produced by wind. Drilled shafts are conventionally used as foundations for sound walls, which can be constructed to provide significant lateral resistance. Using H-piles as an alternative can provide faster installation and immediate utilization, however, they may lack the required stiffness to adequately support these forces. To address this, a modified H-Pile concept was developed which includes one or two plates welded along the pile web to increase the pile-soil surface area perpendicular to lateral loading thus increasing its resistance. In addition, using steel piles improves the sustainability of the system. Used steel is manufactured using two processes BOF and EAF. The recycled content ranges from 37% to 89%.  A full-scale pile load testing program comprising monotonic and cyclic lateral load tests was performed on fourteen steel piles including unmodified steel piles to comparatively evaluate the influence of adding plates to H-piles. Two drilled shafts were also tested as a baseline to compare current practice against the proposed system.  A numerical model was developed with LPILE which was calibrated and validated using the experimental results and then used to conduct a parametric study considering different plate dimensions and a range of practical soil conditions. A second numerical model was developed using GSNAP to extend the cyclic lateral load analysis to simulate higher loads and more load cycles.  H-piles modified with plates had an approximately 22% higher lateral load capacity. The corresponding parametric study demonstrated that widening the plate is typically more efficient for increasing the pile’s lateral capacity than increasing the plate length. The cyclic lateral load tests revealed that the lateral stiffness of the novel piles remains approximately constant within 100 cycles. The GSNAP model simulated that the pile will experience less than 10 mm of ground level deflection at 1000 cycles of the design lateral load.]]></description>
      <pubDate>Tue, 01 Dec 2020 13:58:20 GMT</pubDate>
      <guid>https://trid.trb.org/View/1754889</guid>
    </item>
    <item>
      <title>Karakterisering av dynamiska laster på bullerskärmar och andra lätta</title>
      <link>https://trid.trb.org/View/1748858</link>
      <description><![CDATA[The project focuses on the characterization of aerodynamic loads from railway traffic on noise barriers and lightweight constructions. Noise barriers are submitted to wind load and aerodynamic load from passing trains. The usual wind load is defined in SS-EN 1991-1-4 and depends on the location as well as the surrounding terrain. For design purposes the aerodynamic load is considered as a quasi-static load and is defined in SS-EN 1991-2. It depends among other things on the distance from the centerline of the track, the shape of the train (aerodynamics) and the square of the train velocity. The dynamic effect which is dependent on the structures response is considered through the use of a magnifying dynamic factor. With increasing train velocity, the aerodynamic load is becoming more critical to the design as it influences the static load cases (failure as well as deformations) and above all the stress ranges for fatigue. In order to meet the requirements for both safety and efficiency it is therefore important that the aerodynamic load and in particular the dynamic factor are assessed in a correct manner. Earlier load models which have been reasonable at relatively low speeds need to be adapted to new conditions with higher train velocity and larger number of load cycles. The goal of the project is to develop a more consistent model of the dynamic load from Swedish trains on noise barriers and other lightweight structures and to analyze their dynamic response to this type of loading. The results should provide the basis for a) Validation of SS-EN 16727-22:2016 under Swedish conditions and clearer requirements from contractors for effective procurement as well as b) Development of better requirements regarding the number of load cycles for the design for fatigue of load bearing structures for noise barriers and similar constructions.]]></description>
      <pubDate>Mon, 02 Nov 2020 14:09:01 GMT</pubDate>
      <guid>https://trid.trb.org/View/1748858</guid>
    </item>
    <item>
      <title>Bullerskydd med hastighetsdämpande egenskaper</title>
      <link>https://trid.trb.org/View/1660905</link>
      <description><![CDATA[The purpose was to demonstrate that a successively denser interval of vertical markings on noise barriers near the road can slow down the mean speed. The concept has the potential to be a cost-efficient alternative or complement to road markings and road signs. The method for investigation was a field experiment to measure the speed before, during, and after the time period when the test markings were mounted. The results showed no effect of the test markings. It is possible that another type of traffic environment is needed than the type studied in the current field experiment in order to affect the drivers to slow down.]]></description>
      <pubDate>Wed, 23 Oct 2019 11:22:05 GMT</pubDate>
      <guid>https://trid.trb.org/View/1660905</guid>
    </item>
    <item>
      <title>Feasibility assessment of various TL-5 safety noise barrier (SNB) designs</title>
      <link>https://trid.trb.org/View/1480559</link>
      <description><![CDATA[Major high-speed roads are prevalent in urban areas, and thus there are space constraints in roadside design, particularly when the roadside needs to accommodate both road safety barriers and road noise barriers. A combined road safety barrier and road noise barrier structure is termed a Safety Noise Barrier (SNB). This study was established to better understand the issues surrounding structural design of SNBs, with a particular emphasis on crashworthy SNBs that are capable of achieving a crash test level rating of Test Level 5 (TL-5). A theoretical impact loading model was created after reviewing crash test literature and conducting an indicative vehicle–SNB crash simulation. A design load of 500 kN was established. Incorporating some design scope limitations, nine SNB options were developed, and these were priced and analysed through an eight-variable multi-criteria analysis process. A cost analysis found that SNB options based on a standard slip-formed TL-5 concrete barrier were cheaper than the systems based on discrete posts with longitudinal rails. Also, the use of the TL-5 single slope barrier as a safety barrier element was preferred to the discrete post arrangements. Rigid SNB systems were also clearly favoured over flexible and partially flexible systems.]]></description>
      <pubDate>Mon, 21 Aug 2017 11:40:51 GMT</pubDate>
      <guid>https://trid.trb.org/View/1480559</guid>
    </item>
    <item>
      <title>Wirksamkeit von Laermschutzwandaufsaetzen</title>
      <link>https://trid.trb.org/View/1454029</link>
      <description><![CDATA[Die akustische Wirksamkeit von Wandaufsaetzen auf Laermschutzwaenden wird in der Fachliteratur sehr widerspruechlich angegeben. Hohen theoretischen Schalldruckpegelminderungen von bis zu 10 dB bei Berechnungen mit Simulationsprogrammen stehen nur geringe Pegelminderungen von hoechstens 2 bis 3 dB bei Feldmessungen entgegen. Diese messtechnisch ermittelten geringen Pegelminderungen weisen zudem durch eine unvermeidbare grosse Variabilitaet der meteorologischen Bedingungen bei der Schallausbreitung eine grosse Unsicherheit auf. Die akustische Wirksamkeit von Wandaufsaetzen ist somit meist kaum groesser als die einer Erhoehung der Wand alleine. Die Untersuchungen an Aufsaetzen auf Laermschutzwaende betreffen vorwiegend solche, die eine geometrische Modifikation in Querrichtung zur Laermschutzwand aufweisen, in der Hoehe jedoch konstant sind. Im Rahmen dieser Forschungsarbeit sollen weitere theoretische und praktische Untersuchungen erfolgen, die auch die Altersbestaendigkeit des eingesetzten Materials betreffen. ABSTRACT IN ENGLISH: Literature differs greatly on the subject of acoustic efficacy of noise barrier tops.  The high noise level reductions of up to 10 dB which can be achieved theoretically in calculations using simulation programs are contrasted with only slight noise reductions of 2 to 3 dB at most in field tests.  In view of the unavoidable high variability of meteorological effects on sound propagation, there is also considerable uncertainty surrounding these small noise level reductions.  The acoustic efficacy of barrier tops is therefore usually barely greater than that achieved simply by raising the barrier height.  Tests have predominantly been conducted on the tops of barriers with a geometric modification transversely to the barrier whilst keeping the height constant.  Other theoretical and practical tests are to be conducted in this research work also on the durability of the material used.]]></description>
      <pubDate>Thu, 09 Feb 2017 08:40:13 GMT</pubDate>
      <guid>https://trid.trb.org/View/1454029</guid>
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