Noise Barriers Research Articles

Absorptive noise barrier development

This paper reveals the development of an absorptive, self-supporting noise barrier panel for external applications. Designed for use as a temporary external noise barrier for construction sites and roadside noise barriers. The absorptive noise barrier panel is a module base design that is easy to assemble, disassemble, and re-deploy. The barrier panel utilizes recycled plastic materials, such as milk bottles and other soft plastics, making it one of the most environmentally friendly products. The barrier is manufactured in one process via a unique rotation molding method. It is weather resistant, aesthetically appealing, and offers great design flexibility. Standard size panels are 100 mm thick, by 2000 m wide x 500 mm high. The acoustic design is modeled to achieve NRC 0.85 at 100 mm thick based on an advanced air-flow resistive layer technique combined with an air cavity. The actual sound absorption measurement results are well in line with the predicted modeling. Such a case study potentially uncovers a whole new range of innovative absorptive noise barriers. Further studies and investigations are also recommended.

Unifying low and high-frequency noise mitigation: A novel dual noise barrier approach

Road highways and urban areas often employ noise barriers to shield residential areas from excessive traffic noise. Despite continuous efforts, developing materials for noise barriers that can effectively mitigate noise across a wide frequency range is still a challenge. Specifically, creating a single material capable of attenuating both low and high-frequency noise has proven to be a daunting task. Current practices incorporate porous materials for absorbing low-frequency noise at specific locations. To address this limitation and offer a technique for traffic noise reduction, this research proposes a novel approach utilizing two hindrances: pores for low-frequency and bristles for high-frequency sound waves. An ANSYS Harmonic Acoustic module simulation was conducted to assess the proposed technique's effectiveness. The simulation encompassed geometry definition, material selection, boundary condition constraints, meshing, and analysis. The results indicate a significant reduction in noise at high frequencies (16 000 Hz) of approximately 30 dB, decreasing from 101.4 to 68.1 dB. This demonstration showcases the potential of a staggered arrangement of bristles and pores to handle a wide range of frequency content and effectively mitigate both low and high-frequency traffic noise. The novel dual noise barrier approach offers a promising solution to combat diverse traffic noise challenges, providing a more peaceful soundscape for urban residents.

Managing noise and vibration on mega projects in Australia

The last decade has seen the emergence of the mega project in Australia, including Sydney Metro, WestConnex, Western Sydney Airport, Cross River Rail, Melbourne Metro, and North East Link Project. These projects provide challenges in the management of noise and vibration due to site constraints, proximity to sensitive receivers and condensed project timelines. While the environmental noise and vibration regulation of these projects can differ from state to state, the design process remains largely the same. This paper looks at noise and vibration design and management on some of Australia’s biggest infrastructure projects. Design considerations include physical mitigation measures such as acoustics sheds, noise barriers, temporary noise barriers or enclosures, and ventilation mitigation. Management measures and development of ongoing management tools are described. Finally, this paper reflects upon the overall noise and vibration outcomes in terms of impacts on the affected communities compared with cost of mitigation.

Design Of aesthetic acoustic metamaterials window panel based on Sierpiński triangle for sound-silencing with free airflow

Design of high-efficiency, low frequency (<1000Hz) soundproof window or wall absorber which is transparent to airflow is presented. Due to the massive rise in human population and modernization, environmental noise has significantly risen globally. Prolonged noise exposure can cause severe physiological and psychological symptoms like nausea, headaches, fatigue, and insomnia. There has been continuous growth in building construction and infrastructure like offices, bus stops, and airports due to urban population. Generally, a ventilated window is used for getting fresh air into the room, but at the same time, unwanted noise comes along. Researchers used traditional approaches like noise barrier mats in front of the window or designed the entire window using sound-absorbing materials. However, this solution is not aesthetically pleasing, and at the same time, it is heavy and not adequate for low-frequency noise shielding. To address this challenge, we design a transparent hexagonal panel based on Sierpiński fractal triangle which is aesthetically pleasing, demonstrates normal incident sound absorption coefficient more than 0.96 around 700 Hz and transmission loss around 23 dB, while maintaining air circulation through triangular cutout. Next, we present a concept of fabrication of large acoustic panel for large-scale applications which lead to suppressing the urban noise pollution

NOISE BARRIERS EFFICIENCY DEPENDENCE ON THEIR SHAPE AND GEOMETRY

The work examines noise barriers and evaluates their effectiveness when changing their geometry and shape. Noise barriers are one of the most effective and widely used methods of reducing noise caused by road and railway transport. The effectiveness of the barrier depends on the materials used in the construction, the barrier’s height, geometry, shape, and the acoustic properties of the additional elements installed on top of the barriers. The aim of the work is to review and analyze the scientific literature, which would allow to evaluate the dependence of the acoustic characteristics of noise-reducing barriers on the geometry and shape of the barrier, and to provide recommendations for the design and selection of noise barriers.

Framework to assess the resilience of the motorway network in Austria

In the context of ageing of road infrastructure and increasing hazards due to climate change, it is important to allocate available funds for construction works and maintenance such that functionality loss is minimised in its extent and duration. In other words, the aim is to increase the resilience of infrastructure. In this paper, the outcomes of the project REMAIN (REsilient MotorwAy INfrastructure) are presented. Within REMAIN, a framework was developed to assess the resilience of the whole motorway infrastructure in Austria, considering five distinct asset categories: bridges, tunnels, noise barriers, retaining walls, and roadways. The resilience was assessed regarding 18 hazards of natural, technical, and human origin. The framework is designed to provide the motorway operator with a series of performance indicators solely based on resilience aspects. It is intended to constitute an additional decision-making basis for infrastructure maintenance prioritisation, next to already existing indicators, e.g., condition-based indicators. Emphasise was placed on making the framework executable also in cases of limited data availability, however, additional data can be integrated easily. The ability to predict the resilience of the motorway infrastructure of a whole country regarding all major hazards makes the presented framework unique regarding the comprehensiveness of applicability.

Advancements in Solar Panel Technology in Civil Engineering for Revolutionizing Renewable Energy Solutions—A Review

Globally, solar energy has become a major contributor to the rapid adoption of renewable energy. Significant energy savings have resulted from the widespread utilization of solar energy in the industrial, residential, and commercial divisions. This review article comprises research conducted over the past 15 years (2008–2023), utilizing a comprehensive collection of 163 references. Significantly, a considerable focus is directed towards the period from 2020 to 2023, encompassing an extensive investigation into the latest developments in solar panel technology in civil engineering. The article examines the incorporation of solar panels into building designs and addresses installation-related structural considerations. In addition, the present review examines the applications of solar panels in terms of innovative infrastructure development applications of solar panels, such as photovoltaic parking lot canopies and photovoltaic noise barriers, which contribute to improved energy efficiency. It also emphasizes their role in water management systems, including water treatment plants, water pumping and irrigation systems, energy-efficient solar desalination technologies, and promoting sustainable water practices. In addition, this study examines how solar panels have been incorporated into urban planning, including smart cities and public parks, thereby transforming urban landscapes into greener alternatives. This study also examined the use of solar panels in building materials, such as façade systems and solar-powered building envelope solutions, demonstrating their versatility in the construction industry. This review explores the diverse applications of solar energy, which promotes sustainable practices in various industries. Owing to the ongoing research, solar energy holds great promise for a greener and cleaner future.

Acoustical Analysis of Insertion Losses of Ceiling Materials

This study concentrates on measuring, analyzing and recommending the ceiling materials most suited for the reduction of distinct frequency noise levels with focus on rain noise. A frequency analyzer has been used to measure and obtained accurate sound level (LP) data of the rain noise outside, and inside five buildings with diverse acoustical ceiling materials in South Eastern Nigeria. It was done with and without the ceiling partition (or noise barrier) for the audio and narrow frequency band without contribution from other outdoor-related noise sources. Insertion losses of the ceiling materials were calculated using the data obtained from the measured LP. Result obtained from the analysis indicated that the ceiling material found to effectively reduce the noise levels from external noise source. The type for speech reception threshold frequencies of more than 125 Hz and higher audiometric range was moabi wood with peak LP of 21.20 dB at 500 Hz. While for lower frequencies where the ears are least responsive was plaster of Paris (POP) with peak LP of 12.61 dB at 62.5 Hz. This makes “moabi wood” most suitable in lecture rooms, conference halls and large auditoriums as ceiling material, in consideration of its capability to provide notable attenuation of rain noise within the building. This is in accordance with several other studies done on this subject. In general, at much low frequencies and frequencies greater than 2k Hz significant reduction in the rain noise level was observed.

Life‐cycle performance of noise barriers focusing on installation conditions of fasteners

AbstractThis concept paper discusses the effects of the installation condition of fasteners on the life‐cycle performance of noise barriers. Noise barriers that are erected along high‐speed railway lines are loaded by aerodynamic pressure and suction waves due to the passing trains. As an integral part of railway infrastructures their level of safety must be maintained throughout their entire lifetime. On basis of this concept and study, a potential monitoring‐based approach for the assessment of the life‐cycle performance of NBs is briefly introduced. That monitoring‐based approach finds its place in a holistic four‐stage assessment framework, in other words a progressive four‐stage model in which the information content increases with each model stage and thus successively increases the accuracy of the determined structural conditions at the time of observation and the prediction for the remaining service life of the structure. The objectives of this paper should bring relevant insights for the whole holistic four‐stage model. Depending on how far the degradation of the considered noise barrier has already progressed, the corresponding stage of the holistic assessment concept is activated, which enable infrastructure managers to plan their future investments regarding maintenance, retrofit or rebuilt of noise barriers more economically.

Simulation and experimental study of active noise barrier based on multiple-channel and decentralized system design

Active noise barrier (ANB) was helpful to enhance the noise reduction performance of noise barrier especially in low-frequency range. But it was quite difficult to realize an ideal effect in the far-field as most of the exiting work of ANB took the realization of soft boundary at the edge of noise barriers as the target. An active control strategy based on the decentralized system design was proposed in this paper. The virtual sensor technology was used in order to obtain the far-field noise signal with the help of near-field sensor, while multiple-channel design of both centralized system and decentralized system was studied. An experimental ANB system was then built in semi-anechoic chamber. The performance of the above control strategies was calculated with the actual measured parameters, and the advantages and disadvantages of different systems were compared and studied. The effectiveness of the new strategy was verified through the noise reduction tests of active noise control. The ANB established in this paper which was based on decentralized system design, could be extended to large scale usage directly in the future.

Ultra-broadband acoustic ventilation barrier based on multi-cavity resonators

The numerical simulations and experimental results of an ultra-broadband acoustic ventilation barrier composed of periodic unit cells are reported in this paper. Based on multiple mechanisms, including sound absorption by eigenmodes of the unit cell and sound reflection by a plate structure on upper surface of the unit cell, a single-layer ventilation barrier with broadband sound reduction is designed, and its working bandwidth can reach about 1560 Hz. The experimental results accord well with the simulation results. Furthermore, two types of three-layer ventilation barriers are designed and demonstrated by using the unit cells with different values of a (the length of the hollow square region) and w (the width of the channel between the adjacent cavities), and the bandwidths of both ventilation barriers can increase to 3160 Hz and 3230 Hz, respectively. The designed barrier structures have the advantages of ultra-broadband sound reduction and ventilation, which paves the way to designing high-performance ventilation barriers for the applications in environmental protection and architectural acoustics.

Remedial measures works programme for Slovenian motorway infrastructure

AbstractThe motorway infrastructure consists of pavements, bridges, tunnels, noise barriers, drainage systems, electro‐mechanical equipment and road furniture. All of them need to be at the adequate performance levels to ensure appropriate availability, comfort and safety. To fulfill this condition, road authorities must regularly carry out maintenance, rehabilitation and reconstruction works. As engineering structures have various service lives, performing remedial works for each individual structure at the optimal time would result in frequent road closures on the same road sections, significantly reducing the road availability for the users. Consequently, a works programme of remedial measures is needed which combines the measures on the same road section to the same time frame. The times planned for performing remedial measures therefore cannot be optimal for every structure in the road network, however they can be optimal from the road's availability and total costs perspective. An appropriate coordination between individual types of infrastructure, selection of measures and a method of merging these measures to the individual road sections must be performed. The paper discusses the integration of the results of individual management systems into a unified works programme.

Exploring Noise Pollution, Causes, Effects, and Mitigation Strategies: A Review Paper

Noise pollution, often regarded as a silent menace amidst the clamor of more conspicuous environmental concerns, is a pervasive and escalating issue with profound implications for humanity and the natural world. This comprehensive review paper delves into the multifaceted realm of noise pollution, encompassing its diverse causes, far-reaching effects, and the array of strategies deployed to mitigate its adverse consequences. Within this paper, we embark on an exploration that begins by scrutinizing the intricate tapestry of noise pollution's origins. We dissect the urban sprawl and infrastructure development that spawns construction-related tumult, the transportation networks that propagate incessant road, air, and rail noise, and the industrial activities that generate relentless auditory dissonance. These sources collectively converge to create a symphony of cacophony that increasingly defines modern existence. The effects of noise pollution extend beyond mere annoyance. We scrutinize its deleterious impact on human health, from sleep disturbances and cardiovascular diseases to cognitive impairments and stress-related disorders. We unravel the psychological ramifications, including reduced cognitive performance, annoyance, and social isolation. Furthermore, we delve into its insidious intrusion into the natural world, disrupting wildlife behavior, habitats, and reproductive success. Noise pollution also exerts socio-economic repercussions, diminishing property values and impairing learning environments. Mitigation strategies emerge as our beacon of hope. Regulatory measures, noise barriers, urban planning, technological innovations, public awareness campaigns, and international cooperation collectively form our arsenal in the battle against noise pollution. By recognizing noise pollution as an environmental challenge with profound ramifications and by collectively deploying these strategies, we aspire to cultivate a quieter, healthier, and more harmonious world for present and future generations, echoing a harmonious symphony of coexistence amidst the urban bustle.

Managing Environmental Noise with Mobile Noise Barriers - a Case Study of a Dolomite Quarry in Slovakia

This paper addresses the issue of environmental noise from mining operations, focusing on the specific case of a quarry located in the municipality of Trebejov, Slovakia. The study aims to demonstrate an effective approach to reducing noise pollution through the implementation of mobile noise barriers. The research was motivated by the negative impact of noise from the processing line on the well-being of the population residing in the vicinity of the facility. The study involved conducting extensive noise measurements at various locations surrounding the quarry. The collected data were analyzed to assess the existing noise levels and identify the areas of highest noise exposure. Based on the findings, the implementation of mobile noise barriers was proposed as a solution. The results of the study demonstrated that the mobile noise barriers successfully reduced the noise levels below the legal limits, significantly improving the well-being of the population living near the quarry. The case study opens up the possibility of using mobile noise barriers in other areas and operations with high noise exposure.

Numerical analysis on the cooling and electrical performances of photovoltaic noise barrier

A photovoltaic noise barrier (PVNB) is a useful device for installing PV systems on a noise barrier, which can save the space and cost associated with the installation of PV systems. Since a noise barrier usually consists of porous materials with low thermal conductivities, investigation on the cooling performance of the PVNBs is essential because the temperature of the PV module has a significant impact on its electrical performance. In this study, the cooling and electrical performances of a PVNB were numerically investigated using four different models: PV module-only, PVNB model without a heat sink, PVNB model with a conventional heat sink, and PVNB model with the proposed heat sink configuration. The simulation was validated by comparing the predicted and measured cell temperatures of the PV module at different heat fluxes, and the results showed good agreement. The average cell temperature in the PVNB model without a heat sink significantly increased by 42.2% from 86.98 ℃ to 123.66 ℃ because of the low thermal conductivity of the noise absorber, compared to the PV module only case. In the case of proposed heat sink configuration, the average cell temperature decreased by 42.7% from 123.66 ℃ to 70.90 ℃, compared with the PVNB model without a heat sink, owing to the additional injection of the cold ambient temperature air to the heat sink channel as well as natural convection and stack effect. The electrical performance of the PVs in the tested PVNBs was analyzed, and the results indicated that the maximum output power and voltage in the PVNB with the proposed heat sink configuration increased by 26.6% and 19.0%, respectively, compared to the PVNB model without a heat sink. The results of this study provide useful fundamentals regarding natural convection and the stack effect for optimizing heat sink designs for PVNB.

Enhancing Air Traffic Management and Reducing Noise Impact: A Novel Approach Integrating Băneasa Airport with Otopeni RO Airport

Over the years, Bucharest’s Henri Coandă International Airport has registered a constant and high increase in air traffic, in terms of both passengers and aircraft movements. This paper presents a traffic diversion solution for the Otopeni RO airport, which aims to alleviate air traffic congestion by redirecting a proportion of the planes to the nearby airport at Băneasa. The primary challenge faced by diversion to Băneasa Airport is the proximity of residential areas to the runway at distances of less than 300 m, resulting in significant noise pollution issues. At Otopeni Airport, the main operators use aircraft equipped with CFM 56 turbo engines; therefore, this study begins with an evaluation of the noise directivity of a CFM aircraft engine via measurement. The data thus collected enabled the identification of the dominant frequencies in the acoustic spectrum of the engine noise. A resonant screen solution has been proposed as a solution for Băneasa Airport, emphasizing the importance of implementing solutions to address the noise pollution faced by those living near Băneasa Airport, due to its proximity to the residential area. Various configurations of perforated metal sheets with different perforation patterns were compared to the test performance of solid sheets to optimize noise absorption. Using the impedance tube tests to achieve the highest absorption coefficient, it was determined that the optimal distance between the perforated metal sheets and the resonant screen was 30 mm. Based on the CFM 56 turbo engine noise directivity and the impedance tube tests, a multitude of numerical simulations were conducted using the IMMI software (IMMI 2011). The simulations were performed for two scenarios with and without an acoustic barrier, accounting for the typical configuration of two engines on an aircraft. The results indicate a reduction of 15 dBA with the implementation of a 4-m-high acoustic barrier, in the case of a CFM 56 engine operating at full throttle while the aircraft is on the ground. Through numerical simulations, the optimized resonant screen demonstrated its potential to significantly reduce noise levels, thereby enhancing the overall acoustic environment and quality of life for the communities surrounding Băneasa Airport. The identified findings could serve as a basis for further research and the implementation of innovative solutions to manage air traffic and reduce the impact of aircraft noise in surrounding areas.

A modular design approach for porous green sound-absorbing concrete for the noise barrier on high-speed railway

Recycled aggregate porous concrete is a new type of concrete that saves natural aggregates, realizes the utilization of waste, and has the advantages of environmental protection and sustainability. However, the poor sound absorption coefficient (SAC) and the noise distribution of high-speed railway is not concentrated hinders its application to sound barriers. This study introduces a method of modular design, which includes adjusting the thickness, surface holes design, and modular combination, and the combination strategy of the modules is investigated. In this study, the porous concrete was mainly comprised of tiny and middle ceramsite recovered from waste as aggregate and cement as cementitious material. In order to investigate the effect of holes and modular combination, specimens were drilled holes on the surface, and the diameter of the holes was divided 10 mm and 5 mm. The depth of the holes is varied. The SAC of the sample in the range from 50 Hz to 1700 Hz is tested by the impedance tube and the average SAC of the sample is calculated. In addition, this study applies artificial neural networks to predict the result of the combination strategy. The results show that increasing thickness can improve the SAC of the material at low frequencies, the single module can improve the sound absorption coefficient at specific frequencies by 75%, and the combination of modules can achieve an average SAC of 0.73. The combinations with continuous holes connecting the surface have the best effect. Artificial neural networks can predict this effect accurately. The modular design method in this study provides a solution to the limited application of porous concrete with recycled aggregates.

Repeatability of the European Standardized Method for Measuring Sound Reflection and Sound Insulation of Noise Barriers

The EN 1793-5 and EN 1793-6 standards have been in use for many years as a method for measuring the intrinsic characteristics of noise barriers installed along highways and railways. They require a sound source and a grid of microphones, to be placed near the barrier and in free field conditions, according to predetermined distances. In principle, small errors in positioning the sound source and microphone grid may affect the results obtained. An international round-robin test was carried out in 2012 to evaluate the repeatability and reproducibility of the method, but until now no studies have been carried out to evaluate and compare the repeatability of laboratory versus in-place measurements performed with the same equipment and its variance when an imperfect positioning of sound source and microphones is taken into account. In the present work, multiple series of sound reflection index and sound insulation index measurements performed on noise barriers of the same kind installed in the laboratory or along a highway are presented. The measurements were repeated in different ways: (1) in the laboratory, leaving the source and microphones unmoved to assess the repeatability of the results and of the measurement system under controlled conditions; (2) in the laboratory, repositioning for each measurement the source and microphone grid to assess the robustness of the method under real conditions but in a controlled environment; (3) in situ, along a highway open to traffic, repositioning for each measurement the source and microphone grid to assess the repeatability of the method under real conditions in a critical environment. In both reflection index and sound insulation index measurements, the standard deviation on single-number ratings in all cases examined is well below the value presented in EN 1793-5 and EN 1793-6, which was obtained from statistical analysis of the international round-robin test performed a dozen years ago, suggesting that expert operators with state-of-the art equipment can achieve much better results now.

Lightweight stiffness-dominated acoustic metamaterial barrier for low-frequency sound

In this study, we experimentally demonstrate a class of lightweight acoustic metamaterial barriers that block low-frequency sound. The acoustic metamaterial barrier is composed of a thin rubber membrane coated over a stiff honeycomb plate. Our findings, combined with high-fidelity finite element simulations, demonstrate that the sound insulation performance of the acoustic metamaterial surpasses the mass law in three distinct frequency ranges: (a) the stiffness law dominates insulation up to 140 Hz, (b) degeneracy and destructive superposition of high-order natural modes dominate within the frequency range of 300–500 Hz, and (c) destructive interference between high-order resonance and membrane resonance dominates in the frequency range of 800–1200 Hz. Notably, our study highlights the potential of high-order shear vibration of the periodic structure for the resonant bending waves of the honeycomb cell that coincide with the wavelengths of longitudinal sound waves in air, thereby offering new design guidelines for lightweight acoustic metamaterial barriers. This study reports for the first time the coincidence of high-order and membrane resonance modes within the honeycomb cell by employing an accurate finite element model and experimental validation.

Modeling impedance boundary conditions and acoustic barriers using the immersed boundary method: The three-dimensional case.

One of the main challenges in time domain wave-based acoustics is the accurate simulation of both boundary conditions and barriers capable of reflecting and transmitting energy. Such scattering structures are generally of irregular geometry and characterised in terms of frequency-dependent reflectances and transittances. Conditions for numerical stability can be difficult to obtain in either case. Immersed boundary methods, which are heavily used in computational fluid dynamics applications, replace boundaries by discrete driving terms, avoiding volumetric meshing and staircasing approaches altogether. The main contribution of this article is a unified numerical treatment of both impedance boundary conditions and barriers capable of transmitting energy and suitable for use in the setting of wave-based acoustics. It is framed in terms of the immersed boundary method within a finite difference time domain scheme, using a dual set of matched discrete driving terms in both the conservation of mass and momentum equations that can be tuned against a desired reflectance or transmittance. Numerical results in three dimensions are presented, illustrating non-porous barriers and impedance boundary conditions, and highlight important features such as spurious leakage through an immersed boundary. A brief demonstration of conditions for numerical stability of the immersed boundary method in this context is provided in an appendix.