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2014
Conference Paper
Titel
Inflatable membrane elements for mobile control of temporary noise sources
Abstract
A large variety of noise barriers are well-known and established on noisy highways, railways and the like. They are to a greater or lesser extend accepted as efficient measures for permanent noise control. However, their acceptance is little if temporary noise sources are considered such as construction sites, open air events and sports fields. This is due to high technical and economical effort. These sources are best tackled by temporary measures. In order to offer a mobile and reusable alternative the acoustic performance of inflatable double-leaf membrane screens has been investigated. Based on reinforced synthetic membranes a coplanar cushion is internally fixed by numerous fibers and laterally closed. Special connections enable easy and quick filling of air in order to achieve pneumatically stabilized flat elements of different size. A model for predicting the sound transmission is based on a double-layer approach incorporating the inner fibrous structure of the membranes and their damping behavior. The corresponding transmission loss has to be clearly regarded in balance with the size (screening efficiency) of the elements to gain the required insertion loss. The in-situ performance can be predicted by using standardized methods. Depending on the site geometry as well as on the noise characteristics of the source a theoretical frequency dependent insertion loss of 10 to 20 dB is accomplishable. Numerous in-situ measurements have validated the potential of these membrane elements which in many cases equal the same noise control performance as achieved by much heavier concrete, metal or wooden barriers of the same size. So, inflatable membrane elements for mobile control of temporary noise sources meet acoustical, economical and ecological demands in a balanced approach.