*2.2.2 Brick and masonry noise barriers*

Brick and masonry noise barrier units are constructed out of either finished brick or masonry made of precast concrete blocks. Both types of noise barriers can

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*Innovative Approaches to Noise Reduction DOI: http://dx.doi.org/10.5772/intechopen.93056*

assembling of the whole noise barrier.

*2.2.3 Free standing noise barriers*

safety reasons.

freestanding walls or facades.

**2.3 Material features**

ties increase the noise barrier efficiency.

be built at the installation site (by hand or machine), or they can be prefabricated in the form of blocks which will be assembled at the installation site. The construction of the noise barriers at the installation site allows greater flexibility and better adaptation to the terrain on which the noise barriers are placed, while the advantage of blocks or modules manufactured in advance in a controlled environment is greater uniformity, better durability and regularly lower costs. A disadvantage of such blocks or modules is the need to allow access and space to work machines (e.g. cranes and transport vehicles) at the installation site area in order to enable the

Free standing noise barriers can be concrete noise barriers moulded at the installation site. The process of building them involves digging the ground for support, laying down a steel reinforcement, pouring concrete, surface treatment and concrete hardening. In this particular construction, the casting and later hardening of concrete are carried out in different weather conditions, which can affect the quality of the final product. The advantage of these noise barriers is the fact that the shape and method of installation can be fully adapted to the terrain, which is the reason why these noise barriers are most commonly used on bridges and viaducts. An additional advantage of such noise barriers is their high structural strength and resistance to damage, which is why, alongside the noise protection and reduction function, they are very often used as retaining walls for separating traffic lanes for

Free standing noise barriers can also be precast or premanufactured, i.e. concrete panels are factory-made under controlled conditions and then delivered to the installation site where they are installed (please see **Figure 6**). Furthermore, free standing noise barriers can be designed as green vertical noise barriers which are shown in **Figure 7**. Currently green vertical noise barriers are becoming more and more popular in cities because, in addition to reducing noise, they also reduce air pollution and they do not take up additional space, i.e. they are built into existing

To conclude, all of the aforementioned types of noise barriers are used as a measure of protection against traffic noise, while the choice of the noise barrier itself depends on the noise level at the location where the noise barrier is installed (i.e. acoustic properties of the sound source). In addition, the selection depends on the position of the noise barrier itself (distance of the noise barrier from the sound

The noise barrier construction can be made of different materials. It is possible to construct a noise barrier with only one material; however, more often the construction of noise barriers consists of several different materials. The choice of materials depends on several basic factors: acoustic properties, type and level of noise sources from which we are protecting a certain space, mechanical properties, aesthetic requirements on both sides of the noise barrier, regulations and the cost of an investment in noise protection for a certain space. In addition to the abovementioned and described basic materials (concrete, metals, wood, etc.), soundabsorbing materials (e.g. stone wool) are often used in practical case scenarios. Such materials can be used as noise barriers' fill and with their sound absorption proper-

source and the receiver) and the allowed noise barrier height.

#### *Innovative Approaches to Noise Reduction DOI: http://dx.doi.org/10.5772/intechopen.93056*

*Noise and Environment*

mounted between the base posts. The basic elements of this noise barrier type are the post and the elements which attach it to the foundation, the panels and the ele-

• Reinforced concrete foundation with a post anchored to the top of the founda-

• Reinforced concrete foundation where the post is partially embedded in the

• Unreinforced concrete foundation with post submerged to full depth of

Brick and masonry noise barrier units are constructed out of either finished brick or masonry made of precast concrete blocks. Both types of noise barriers can

• Wooden posts dug into drilled cylindrical holes with stone fill.

There are several ways to set up or build a foundation for posts:

ments which attach the panels to the posts.

concrete mass during concreting.

• Continuous foundation wall.

*2.2.2 Brick and masonry noise barriers*

foundation.

**Figure 6.**

*Green vertical noise barriers.*

tion using anchor bolts.

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be built at the installation site (by hand or machine), or they can be prefabricated in the form of blocks which will be assembled at the installation site. The construction of the noise barriers at the installation site allows greater flexibility and better adaptation to the terrain on which the noise barriers are placed, while the advantage of blocks or modules manufactured in advance in a controlled environment is greater uniformity, better durability and regularly lower costs. A disadvantage of such blocks or modules is the need to allow access and space to work machines (e.g. cranes and transport vehicles) at the installation site area in order to enable the assembling of the whole noise barrier.
