They also known as sound walls, are structures designed to reduce the amount of noise pollution caused by traffic, railways, industrial facilities, and other sources of sound. These barriers are typically made of metal and are installed along highways, railway tracks, and other noisy areas to create a physical barrier between the source of the noise and nearby communities.
Design and Construction
The design of a metallic noise barrier depends on a variety of factors, including the type and intensity of the noise, the distance between the noise source and the barrier, the topography of the surrounding area, and the needs of the community. Generally, they consist of metal panels or sheets that are mounted on a framework of steel or aluminum posts. The panels may be coated with sound-absorbing materials such as mineral wool, fiberglass, or foam, to enhance their noise-reducing capabilities.
The height and length are crucial factors in its effectiveness. The height of the barrier should be sufficient to block the line of sight between the noise source and the receiver, while the length of the barrier should be long enough to redirect the sound waves away from the receiver. The angle of the barrier is also important, as it can affect the reflection and diffraction of sound waves.
There are several methods of constructing metallic noise barriers, including precast concrete panels, modular steel systems, and custom-designed systems. Precast concrete panels are pre-fabricated offsite and transported to the construction site, where they are installed using cranes or other heavy machinery. Modular steel systems, on the other hand, consist of pre-engineered panels that can be assembled on-site using bolts or welding. Custom-designed systems are tailored to specific project requirements and may involve a combination of different materials and construction methods.
The effectiveness of metallic noise barriers in reducing noise pollution depends on several factors, including the type and intensity of the noise, the design and construction of the barrier, and how far away the receiver is from the source of the noise. Generally, they can reduce noise levels by 5 to 10 decibels (dB) on average, with the amount of reduction increasing with the height and length of the barrier.
The performance can also be influenced by weather conditions such as wind, rain, and temperature. Wind can affect the transmission of sound waves over the barrier, while rain and temperature changes can cause expansion and contraction of the barrier materials, leading to potential gaps or cracks that can reduce the barrier’s effectiveness.
Another factor that can affect the performance is the presence of gaps or other openings in the barrier. Even small gaps can significantly reduce the effectiveness of the barrier, as they allow sound waves to pass through and reach the receiver. Therefore, it is essential to ensure that they are properly installed and maintained to minimize any gaps or other openings.
They are an effective solution to reduce noise pollution in areas where traffic, railways, and other sources of sound can cause significant disturbance to nearby communities. The design and construction of these barriers are crucial in their effectiveness, and the use of sound-absorbing materials and proper installation techniques can significantly enhance their noise-reducing capabilities. However, it is important to note that they are not a complete solution to noise pollution, and other measures such as traffic management, speed reduction, and public transportation should also be considered to address the root causes of noise pollution.