No / Recent progress in the development of European standards has allowed the in situ testing of roadside noise barriers. CEN/TS 1793-5 describes a test method using maximum length sequences (MLS) for the characterisation of airborne sound insulation. However, many barriers are tested according to a laboratory standard, EN 1793-2, based on measurements carried out in reverberant chambers and in the case of timber barriers with a relatively low airborne sound insulation it is not clear to what extent the results of the two tests compare. The paper describes the results of tests carried out using both methods. Six samples of timber barrier were compared including single-leaf and double-leaf constructions and single-leaf constructions with an absorptive core. Very good agreement was found especially when account was taken of the valid frequency range in each test method. The results open up the possibility of routinely evaluating the performance of timber barriers at the roadside where build quality can be variable and there are concerns that the acoustic performance may not match that obtained under laboratory test conditions where typically the barrier is more carefully constructed.

Yes / The in situ measurement of the airborne sound insulation, as outlined in EN 1793-6:2012, is becoming a common means of quantifying the performance of road traffic noise reducing devices. Newly installed products can be tested to reveal any construction defects and periodic testing can help to identify long term weaknesses in a design. The method permits measurements to be conducted in the presence of background noise from traffic, through the use of impulse response measurement techniques, and is sensitive to sound leakage. Factors influencing the measured airborne sound insulation are discussed, with reference to measurements conducted on a range of traffic noise barriers located around Auckland, New Zealand. These include the influence of sound leakage in the form of hidden defects and visible air gaps, signal-to-noise ratio, and noise barrier height. The measurement results are found to be influenced by the presence of hidden defects and small air gaps, with larger air gaps making the choice of measurement position critical. A signal-to-noise ratio calculation method is proposed, and is used to show how the calculated airborne sound insulation varies with signal-to-noise ratio. It is shown that the measurement results are influenced by barrier height, through the need for reduced length Adrienne temporal windows to remove the diffraction components, prohibiting the direct comparison of results from noise barriers with differing heights. / The authors would like to thank the NZ Transport Agency for sponsoring the Auckland traffic noise barrier testing work, and the Auckland Motorway Alliance for assisting with access to the test sites.

I dagsläget dimensioneras bullerskärmar efter varje projekt med den enda gemensamma nämnaren att de skall uppfylla utformade riktlinjer och bullerkrav. De kan skilja sig enormt vad gäller estetisk utformning och konstruktion. Denna arbetsgång är både tids - och kostnadsineffektiv med konsekvenser som följd, framförallt då externa arkitekter anställs för att sätta sin egen prägel. Uppgiften har utdelats gemensamt utav Trafikverket och Peab som ser ett behov utav standardiserade bullerskärmar. Slutsatsen har dragits utav tidigare projekt och då framförallt projekt Mälarbanan. Denna rapport syftar till att, med utgångspunkt Mälarbanan, ta fram ett förslag till ett standardiserat system som skall kunna användas runt om i Sverige. Detta system, skall motverka dagens problematik med nuvarande bullerskärmar. Systemet kommer i texten att benämnas som Bsk 14F som står för Bullerskärm 14 Försök. Resultatet utav Bsk 14F kommer att redovisas med ljudmodelleringar i dataprogrammet INSUL som används i dagens utformningar. Ritningar i CAD kommer att påvisa Bsk 14Fs konstruktion och kalkylräkning för kostnaderna. Vi har även jämfört olika bullerskärmar som finns att tillgå på marknaden idag för att undersöka möjligheten att välja ett befintligt system. Med hjälp av en yrkesverksam akustiker, konstruktörer, platschefer och arbetsledare har vi kunnat erhålla underlag för att producera ett slutligt resultat. Här påvisas att med ett standardiserat system går det att uppnå ljudkraven som erfordras till ett lägre pris utan att behöva kompromissa utrymme för arkitektoniskt prägel. / Ideally, the basic standard forms of how and why noise barriers are created are to fulfill the purpose of reducing sound. They vary greatly regarding their esthetics and design. Particular mechanics are both time and cost ineffective consequentially when external architects are contracted to put their trademark on them. Trafikverket and Peab, whom identify the need of standardizing noise barriers, have collaboratively delegated the assignment. The conclusion has been drawn from earlier projects and Project Mälarbanan. The premise of the report (having Mälarbanan as an example) is to offer a standardized system which would be used throughout Sweden. This system would, thus, counter the current problems with noise barriers that exist today. The system will be noted in the text as Bsk 14F, which stands for Bullerskärm 14 Försök (Noise Barrier 14 experimental). A computer sound-model program using today’s configurations will present the results of Bsk 14F, whereas drawings in CAD will show Bsk 14F’s design and calculation costs. A comparison has also been made to examine the possibility of choosing a noise barrier currently existing on the market today. With the help of effectively using a professional acoustician, engineers, site managers, and project leaders was it possible to obtain the core material to produce an ultimate and final result. The following demonstrates that establishing a standardized system, which fulfills the sound requirements and be constructed at a lower cost, is attainable without having to comprise the architectural trademark.

<p>A three-dimensional computational fluid dynamics (CFD) model has been developed to simulate the distribution of automobile emissions on and near a highway. A variety of k-ε turbulence models were adopted to simulate the turbulence flow, and a non-reaction species model was coupled to simulate the dispersion of emissions. The models were first validated by comparing velocity profiles and normalized emission concentration with wind tunnel experiments, and good agreement was observed. Next, further simulation and analysis revealed that T-shaped noise barriers could reduce more emissions concentration in downstream areas than rectangular noise barriers; however, the noise barrier shape effects on the dispersion of emissions were also influenced by inflow conditions. Thirdly, the traffic flow conditions on the highway made a difference to the dispersion of emissions. Automobile wakes not only existed behind vehicles but also induced turbulence on adjacent lanes, causing more emissions on the highway. Low traffic speed, such as congestion, would result in more emissions remaining on the highway as well. At last, vehicle body shapes modified the flow patterns by their slant angles and heights. Vehicles with slant angles on both front and rear sides had the least concentration of emissions at the center of the highway.</p>

Vid både ny- till- och ombyggnation sker ofta arbete tätt inpå redan befintlig bebyggelse. Då dessa innehåller både kontor, bostäder samt övriga verksamheter är risken stor att dessa påverkas negativt av buller från närliggande byggarbetsplatser. I dagsläget finns allmänna råd som Naturvårdsverket har tagit fram. I dessa går det att utläsa vilka ljudnivåer buller från byggarbetsplatser inte bör överstiga samt under vilka tider på dygnet dessa gäller. Det är viktigt att komma ihåg att allmänna råd inte är bindande utan endast riktvärden som i möjligaste mån bör följas. Tillsynsmyndigheten på Länsstyrelsen ansvarar för att dessa följs och tar beslut i samband med byggnation vilka bullernivåer som är lämpliga. Trots förekomsten av de allmänna råden uppkommer det i stor utsträckning tvister mellan den byggande parten och tredje man. Det behöver inte enbart handla om att råden inte efterföljs utan kan i fler fall bero på andra faktorer, till exempel att informationen om kommande störningar varit otydlig. Klagomål kan även förekomma då riktvärdena följs.   Genom att diskutera bullerproblematiken med byggföretaget STRABAG Projektutveckling AB har kunskap om deras syn och erfarenhet av ämnet inhämtats. Företaget lägger stort fokus på att informera tredje man genom att skylta om kommande störningar. Enligt oss bör företaget dock arbeta mer med bland annat planering av avskärmningar mot omgivande bebyggelse. Hur bullerskärmar bör placeras i förhållande till omgivningen, hur de ska utformas och vilka områden som ska skyddas är viktiga frågor att ta upp redan under planering av projekt. Ytterligare information har inhämtats genom en enkätundersökning och intervjuer med Naturvårdsverket, kommuner och Tillsynsmyndigheten. / Construction work is often performed in close contact to existing buildings such as offices, homes and stores. The people working and living in these buildings may thereby be affected negatively by the noise occurring from the construction site. There are guidelines compiled by Environmental Protection Agency regarding the level of noise that should not be exceeded. It’s important to remember that these guidelines are only guidelines and not binding values. “Tillsynsmyndigheten” at “Länsstyrelsen” is responsible for the adherence of the guidelines and make decisions related to which noise levels are appropriate at the construction site. Even though the existence of the guidelines there are times when the construction company can disturb the third party. This does not always have to do with the fact that the noise levels have been exceeded. It could also occur if the information about upcoming disturbances has been unclear. Complaints may also occur when the guidelines are followed. By interviewing representatives at STRABAG Projektutveckling AB about disturbance caused by noise we have received their opinions and experience in the matter.  The company puts great effort to distribute the information about upcoming noise and posting it on billboards. By our opinion more effort should be added to planning upcoming projects and deciding what kind of protection should be used and the most efficient way of placing it due to its surroundings. These are questions that are to be decided in an early stage of the planning process. Additional information has been obtained through a questionnaire survey and interviews with Environmental Protection Agency, municipality and “Tillsynsmyndigheten”.

[EN] The aim of this work is to design new acoustic devices based on arrangements of scattering units. First, the use of sonic crystals as noise barriers for traffic noise control is comprehensively analyzed. Due to the limitations of the conventional structures based on rigid scatterers, the inclusion of absorbing elements is proposed. Two different types of absorbers are here considered: porous materials and microperforated plates. In the first case, the attenuation characteristics of barriers made with cylinders containing rubber crumb is analyzed. The second proposal is based on the construction of cylindrical microperforated shells. Analytical approaches modelling the behavior of the barriers have been developed in both cases. These models show a satisfactory agreement with the corresponding experimental realizations. Finally, it is performed an optimization process in order to obtain efficient sound barriers intended to attenuate traffic noise. Another application considered in this work is the construction of cloaks to render objects acoustically invisible. In particular, cloaks made with rigid inclusions are designed to operate with airborne sound. The first proposal consists of a cloak that utilizes the temperature of the background to control the properties of the effective medium. In addition, two and three-dimensional cloaks have been developed through the scattering cancellation technique. These devices have been designed by means of an optimization procedure and their performance has been experimentally demonstrated. / [ES] El objetivo de este trabajo es el diseño de nuevos dispositivos acústicos basados en disposiciones de centros de dispersión. En primer lugar, el uso de cristales sónicos como barreras acústicas para el control de ruido de tráfico es analizado en detalle. Debido a las limitaciones que presentan las estructuras convencionales basadas en centros de dispersión rígidos, se propone la inclusión de elementos absorbentes en los mismos. Se han considerado dos tipos distintos de absorbente: materiales porosos y placas microperforadas. En el primer caso se analizan las propiedades atenuadoras de barreras formadas por cilindros que contienen granza de caucho. La segunda solución se basa en la construcción de coronas microperforadas. En ambos casos se han desarrollado modelos analíticos que permiten determinar el comportamiento de las barreras. Dichos modelos muestran un acuerdo satisfactorio con las correspondientes realizaciones experimentales. Finalmente se ha realizado un proceso de optimización con objeto de obtener barreras eficientes para la atenuación de ruido de tráfico. Otra aplicación considerada en este trabajo es el desarrollo de dispositivos de invisibilidad acústica. Concretamente se pretenden diseñar mantos constituidos con elementos rígidos para ondas acústicas en aire. La primera propuesta consiste en un manto que utiliza la temperatura del medio externo para controlar sus propiedades efectivas. Además se han desarrollado mantos en dos y tres dimensiones a través de la técnica de cancelación de la dispersión. Los diseños han sido realizados por medio de un proceso de optimización y su funcionamiento ha sido demostrado experimentalmente. / [CA] L'objectiu d'aquest treball és el disseny de nous dispositius acústics basats en disposicions de centres de dispersió. En primer lloc, l'ús de vidres sònics com barreres acústiques per al control de soroll de trànsit és analitzat en detall. A causa de les limitacions que presenten les estructures convencionals basades en centres de dispersió rígids, es proposa la inclusió d'elements absorbents en els mateixos. S'han considerat dos tipus diferents de absorbent: materials porosos i plaques microperforades. En el primer cas s'analitzen les propietats atenuadores de barreres formades per cilindres que contenen gransa de cautxú. La segona solució es basa en la construcció de corones microperforades. En tots dos casos s'han desenvolupat models analítics que permeten determinar el comportament de les barreres. Aquests models mostren un acord satisfactori amb les corresponents realitzacions experimentals. Finalment s'ha realitzat un procés d'optimització per tal d'obtenir barreres eficients per l'atenuació de soroll de trànsit. Una altra aplicació considerada en aquest treball és el desenvolupament de dispositius d'invisibilitat acústica. Concretament es pretenen dissenyar mantells constituïts amb elements rígids per ones acústiques en aire. La primera proposta consisteix en un mantell que utilitza la temperatura del medi extern per controlar les seves propietats efectives. A més s'han desenvolupat mantells en dues i tres dimensions a través de la tècnica de cancel·lació de la dispersió. Els dissenys han estat realitzats per mitjà d'un procés d'optimització i el seu funcionament ha estat demostrat experimentalment. / García Chocano, VM. (2015). New devices for noise control and acoustic cloaking [Tesis doctoral]. Editorial Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/53026 / TESIS / Premios Extraordinarios de tesis doctorales

Thin-walled, high-strength concrete elements exhibiting low system weight and great slenderness can be created with a large degree of lightweight structure using the textile-reinforced, load-bearing concrete (TRC) slab and a shell with a very high level of sound absorption. This was developed with the objective of lowering system weight, and then implemented operationally in construction. Arising from the specifications placed on the load-bearing concrete slab, the following took place: an adapted fine-grain concrete matrix was assembled, a carbon warp-knit fabric was modified and integrated into the fine concrete matrix, a formwork system at prototype scale was designed enabling noise barriers to be produced with an application-oriented approach and examined in practically investigations within the context of the project. This meant that a substantial lowering of the load-bearing concrete slab’s system weight was possible, which led to a decrease in transport and assembly costs.

Thin-walled, high-strength concrete elements exhibiting low system weight and great slenderness can be created with a large degree of lightweight structure using the textile-reinforced, load-bearing concrete (TRC) slab and a shell with a very high level of sound absorption. This was developed with the objective of lowering system weight, and then implemented operationally in construction. Arising from the specifications placed on the load-bearing concrete slab, the following took place: an adapted fine-grain concrete matrix was assembled, a carbon warp-knit fabric was modified and integrated into the fine concrete matrix, a formwork system at prototype scale was designed enabling noise barriers to be produced with an application-oriented approach and examined in practically investigations within the context of the project. This meant that a substantial lowering of the load-bearing concrete slab’s system weight was possible, which led to a decrease in transport and assembly costs.

Detta examensarbete behandlar bullerskärmar för järnvägen längs Mälarbanan. Det nuvarande utförandet av konstruktionen har visat sig få problem med utmattning av de skruvförband som förbinder bullerskärmen med grundkonstruktionen. Konstruktionen uppfyller inte den tilltänkta livslängden. Examensarbetet föreslår förbättringar av konstruktionen. Denna kan enkelt modifieras, så att skruvförbanden blir förspända vilket minskar lastamplituden. Europeiska regelverk gällande stålkonstruktioner beaktas. Det förnämliga är att de inte fordrar några större eller kostsammare förändraringar av dagens utförande. Två lösningsförslag föreligger och presenteras i rapporten / This thesis project is about railroad noise barriers along the Mälarbanan. The current construction design has been found to have fatigue problems related to the threaded rods connecting the noise screen to the ground structure. This results in the barrier not sustaining the intended life expectancy. The aim of this thesis project has been to improve the current construction design by suggesting solutions enabling the construction to withstand the dynamic loads. The goal of this project has been achieved through reviews of the current construction, previous consulting reports and by taking in consideration the European standards for steel constructions along with Trafikverkets rules and regulations. This has resulted in two solution proposals, for current and future constructions, without the need for major design changes.

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.  A key finding is that the general applicability of existing pressure calculation models is limited because of the wide variation in HST geometries and noise barrier heights. The amplitude of train-induced aerodynamic pressure on vertical noise barriers increases with train height and width but decreases as nose length increases. While taller noise barriers experience greater aerodynamic pressures, the in-crease in pressure with barrier height is not significant. The proposed modified pressure calculation model that accounts for train geometry and the height distribution coefficient predicts the train-induced aerodynamic pressure on vertical noise barriers more accurately than existing models and could thus improve the structural design and safety of HSR noise barriers across a wide range of conditions.