Nicola Granzotto

Analysis of acoustic behavior of bare CLT floors for the evaluation of impact sound insulation improvement

Estimation of the impact sound insulation of horizontal partitions, evaluated from the performance of basic components according to EN 12354-2, does not provide satisfactory results when applied to floors made of Cross-Laminated Timber (CLT) elements. One of the most interesting reasons for this limited match between predicted and measured impact noise values is the difficulty of correlating the reduction of the impact sound pressure level of the floor covering, measured in a laboratory on a concrete slab, with the actual behavior on a bare CLT floor. Reported here are the results of laboratory evaluations, independently carried out by various researchers on similar CLT structures. The purpose of this study is to identify the empirical spectrum of the normalized impact sound pressure level of a reference floor made according to CLT technology, to provide a simple and useful tool for estimating the noise insulation performances of this type of building element.

Improvement of acoustic and thermal performances of façades on retrofit buildings

Deep renovation of existing buildings represents an important strategy to go beyond the standard energy retrofit (as the increasing of thermal insulation of building envelope) and to provide more benefits to residents considering non-energetic aspects, like the improvement of architectural quality of building and of indoor life quality. In this context, facades additional elements (balconies, solar greenhouses, etc.) can be effective solutions in order to increase thermal and acoustic performances as well as providing a more living space to the outside. This paper analyzes and compares different technical construction systems for facade improvement in order to define robust solutions correlated both to outdoor climate context (to increase energy performances towards nearly Zero Energy Buildings) and to outdoor noise for a better acoustic sound insulation. A case study is presented, and dynamic energy simulations, performed on a building made with materials and construction technology widespread in Italy ...

A Combined Experimental and Analytical Approach for the Simulation of the Sound Transmission Loss of Multilayer Glazing Systems

In order to ensure acoustic comfort of living spaces, nowadays façade systems having high performance are required. Within such context the glazing systems play a key role in achieving high levels of sound insulation. The characteristics of sound insulation of such systems can be determined by analytical methods that make use of experimental characterizations of the physical and mechanical parameters of these systems. In this work a combined experimental and analytical approach for sound transmission loss prediction of glazing systems is presented. In particular, the mechanical properties of monolithic and multilayer glasses with viscoelastic interlayer made of polyvinyl butyral (PVB) are measured using resonance curve method of flexural waves on glass beams with different boundary conditions. In order to achieve reliable input mechanical data (Youngs modulus and loss factor), tested beams are characterized in free-free and elastic constraints boundary conditions, respectively. The elastic constrain boundary conditions are realized following the same specifications of ISO Standard 10140 series for larger panels. Starting from the proposed mechanical characterization, the diffuse field sound transmission loss of glass panels has been predicted through an analytical model for solid elastic layers. Results from the above-mentioned procedure are compared with laboratory measurements. From the analysis it will be shown a better accuracy in determining the sound transmission loss of panels when the elastic constrain boundary conditions are applied to the representative beams.