Noise barrier
The noise barrier is used mostly by the side of roadways to reduce traffic noise and air pollution
Noise reduction in itself by building noise barriers is not a difficult problem in noise pollution technology There are different fence-like solutions and noise reduction embankments in use Because a part of the sound bends over the barrier, it is no use building it very sound-insulating, about 20 dB is enough For example a tight carpet weighing about 5 - 10 kg reaches this level Present solutions are heavier than necessary, more expensive and often unsatisfying in appearance Embank¬ ments with vegetation are considered visually more natural, but they take often too much space and require expensive foundation reinforcement on a bad ground
The advantage of the invention is a construction which as light and airy is suited for its role and does not require either accuracy or immobile foundations when it is mounted. The construction does not get dirty as easily as present fences and it is easy to manage. The construction can also function as a crash wall.
The basic idea of the invention is to divide the noise barrier into a carpet-like, quite light, mainly hanging noise reduction plane and a grating-like part which covers the plane and constitutes the visual appearance The plane can be supported by the grating-like part or a separate frame As it is screened from view neither accuracy nor immobile foundations are necessary when it is mounted It can be a tight, weatherproof carpet weighing about 5 - 10 kg/m 2 , covered with stone chips or camouflaged The lower end of the carpet bends partly over the ground or it can be 200 mm off the ground and the noise reduction still remains The visual idea of the grating-like part can be compared to a sparse latticework of a suspended ceiling when you look at it perpendicularly you can see pack discharges and things like that behind it but when you look at it diagonally it forms a ceiling surface The other basis for the appearance of the grating part is that it is "hedge-like Just like a hedge is visually acceptable as "inaccurate' , the grating part is also made such that
neither accuracy nor immobile foundations are necessary when it is mounted. It can stand on the ground without foundations. On its basal part lying against the ground can be put soil as a weight When the grating part is made for example spiral and the noise reduction plane folded or rolled up, the construction can be arranged in a small room for transport and unrolled when it is mounted. The mounting can be done with a mobile crane from a roadway
In the following text are described two typical embodiments by means of the attached drawings
1 : the actual noise reduction plane (1 ) is inside a spiral grating frame (2) The ma¬ terial of the grating can be for example wood, metal or plastic The transversely flat form increases the capability of the grating to screen the plane from view The upper edge of the grating is round whereupon inaccuracy in mounting and movements caused by the frost heaving action of the soil do not make its appearance worse There is soil as a weight on the basal part of the grating part The lower edge of the hanging noise reduction carpet can bend against the ground or hang a bit off the ground. The carpet is a better noise barrier than a stiff sheet of the same weight The design of the grating in the figures is only one alternative of principle There is reason to improve the design under 1 1 real conditions, likewise the appearance of the noise reduction carpet For example it can be characterized by stone chips which increase the weight of the carpet or camouflaged in the army way The con¬ struction works well with vegetation the introduction of which makes the appearance even better.
2: the noise reduction plane (1 ) is supported by a triangular frame and the covering grating (2) lies apart from it The bars of the grating in the figure are slender willow trunks or things like that, hit into the soil in an upright position, which are green in the summer and whose densely planted trunks form a covering grating also in the winter. For example, the bars could as well be dead, round trees in a slightly oblique position, coupled together hoπsontally, leaning against the triangular frame The whole does not require accuracy.
