Noise barrier walls
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Post and panel walls are supported by concrete or steel posts connected to a foundation. The foundation is usually a drilled hole known as a caisson. Steel posts can be installed directly into freshly poured concrete to create the connection. Concrete posts can be inserted full depth into a caisson, or have a partial depth connection. Both steel and concrete posts can be bolted onto a foundation so that they can be removed if necessary. The noise barrier panels slide into the H shaped posts and resist wind loads or retained earth loads, transfering those forces to the post and its foundation.
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Angle Walls are constructed with heavy concrete panels joined with stainless steel cables. The panels are joined at hinged connections and arranged in a trapezoidal pattern to provide stability. They are installed on a shallow crushed stone foundation. This type of wall saves money by reducing foundation costs. It is also visually interesting.
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Acoustics - Walls reduce noise levels by creating a longer path for the sound to travel. Walls must be tall enough and long enough to work properly. The height should break the line of sight to the noise source to be minimally effective. The goal should be to reduce noise level by 10dBA. For example, a 57 dBA sound level is perceived to be half as loud as 67 dBA. So, to get the wall tall enough add about 2 ft per additional dB above the line of sight until you get to the 10dBA goal. The wall should be long enough to encompass a 140 degree field of view from the receiver when looking toward the noise source. Horizontal joints between panels that stack up must be "light- tight" to prevent sound from leaking through. Panels should be sound absorptive to prevent unwanted reflected sound.
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Aesthetics - Architectural patterns for concrete walls can be selected from a variety of sources to look like stone or brick. Concrete walls can be colored in earth tones with durable acrylic stains. Coloration can be applied to walls to make them look like real stone. Clear walls allow the travelling public to enjoy a view or see the community resources from the roadway. Aluminum walls can be powder coated in a variety of colors to fit into an architectural viewscape.
