Highway sound barrier walls works as a sound energy absorber before sound reaches the receiver. Purpose, advantages and design of sound barrier masonry walls is discussed.
- Highway Sound Barrier Masonry Walls
- What is a Highway Sound Barrier Wall?
- What is Transmission Loss in Sound Barrier Wall?
- What is insertion loss in Sound Barrier Wall?
- Purpose of Highway Sound Barrier Masonry Walls
- Advantages of Highway Sound Barrier Masonry Walls
- Design Considerations of Highway Sound Barrier Masonry Walls
Highway Sound Barrier Masonry WallsFollowing points are discussed regarding highway sound barrier masonry walls:
- What is a highway sound barrier wall?
- What is transmission loss?
- What is insertion loss?
- Purpose of highway sound barrier masonry walls
- Advantages of highway sound barrier masonry walls
- Design considerations of highway sound barrier masonry walls
Fig.1: Sound Barrier Masonry Wall
Fig.2: Highway Sound Barrier Wall
What is a Highway Sound Barrier Wall?It is a wall that works as a sound energy absorber before sound reaches the receiver. So, the mission of the sound barrier wall will not be completed unless it absorbs required amount of acoustic energy. The acoustic energy transmission though sound barrier wall depends on several parameters, such as material density and stiffness used the construction of the wall, the angle of sending sound energy, and the range of sound frequency.
What is Transmission Loss in Sound Barrier Wall?Transmission loss is a term used to describe the ability of materials to transmit noise and it is associated with the ratio of sound energy at its source to the transmitted sound energy.
Fig.3: Transmission Loss in Sound Barrier WallConsidering highway noise and other noises in highway noise range, the transmission loss of sound barrier materials increases as the weight of material barrier surface is increased. Table-1 provides transmission loss for different types of materials barrier for different thickness of barriers, and masonry transmission loss can be compared with other types of materials.
Table-1: Transmission Loss for Different Type of Material Barrier
What is insertion loss in Sound Barrier Wall?Insertion loss is a measure of sound barrier effectiveness and it is the difference between the sound prior to the barrier placement next to the highway and after the barrier is constructed close to the highway. The insertion loss consists of five components which are provided by NCMA TEK and the components include:
- Barrier attenuation because of sound wave diffraction around and over a barrier fixed in the line of sight plane between the receiver and the source of the sound.
- Transmission loss of sound through the barrier
- Decrease in barrier attenuation due to number of reflections as a consequent of double barrier.
- Attenuation protection through from other barriers between receiver and the source of the sound.
- Excess attenuation loss already received from soft ground cover.