Innovative building systems to improve the acoustical quality in lightweight masonry constructions: Application of resilient joints at junctions - PART 1: Analysis of the experimental results

Abstract

The more severe acoustic requirements imposed by the new Belgian standard for dwellings are a real challenge for the building professionals (architects, contractors, building elements manufacturers and suppliers, etc) and more particularly for the market of lightweight materials. An important brick producer in partnership with the BBRI has succeeded to propose efficient acoustic solutions for these kinds of materials by treating in particular the flanking transmission. Indeed, to obtain high sound insulations, the structural transmission paths of noise through the flanking walls cannot be neglected any more. By the application of resilient rubber interlayers at the junctions, these transmission paths are nearly eliminated. A large number of measurements was carried out in order to study in detail the effect of these flexible joints on the sound transmission. These measurements were made in a specially designed laboratory where vibration reduction indexes can be measured for all types of connections and for different loads. We present, in this paper, the measurement survey and the analysis of the results.

Innovative building systems to improve the acoustical quality in lightweight masonry constructions: Application of resilient joints at junctions - PART 2: Study cases modelled according to the standard 12354-1 (2000)

“…The vibration reduction index K ij used for the simulation is the one obtained according to the empirical formula from the standard 12354-1 to conserve consistency in the input data. The large number of measurements carried out on rigid junctions [2,3] has showed a good agreement between the measurements and the predictions and thus the relevance to use the calculated value.…”

“…The connections can be for example a continuous floor between two apartments or a common foundation at the ground floor. Measurements [3] made on a cavity wall supported on foundations show the importance of this path and explain why the cavity walls do not reach the expected performance.…”

“…The sound reduction index used in the prediction model results from calculation even though we had the measured value for some cases [3]. In this way, we conserve consistency in the input data used.…”

“…An important measurement survey has been carried out to measure the K ij for a transmission path crossing resilient joints [3]. The original setup permitted to compress the joint to simulate different storeys.…”

“…For these cases only the measurement results are used in the prediction model. The details of these measurements can be read in the article on the measurement survey [3].…”