1,721,116 research outputs found
Acoustic comfort in a worship space made of cross-laminated timber
No full textThe construction of a new worship space in cross-laminated timber provides a good opportunity to include acoustic needs in the whole design development. The surface porosity and the lightweight of wooden elements may be carefully considered in order to improve the intelligibility of priests’ voice. In this work, a practical approach for obtaining a global acoustic comfort using sustainable materials is provided, using geometrical acoustic simulations. Material properties and architectural geometries were taken into account in order to evaluate subjective reverberation, speech intelligibility, and spatial perception over the whole audience. Results show how the sound energy distribution in the case study follows the sound field models proposed by scholars and how the ceiling shape—inspired by industrial sheds—contributes to the acoustic comfort of the faithfuls
The effect of damping in Resilient materials used in floating floors on impact sound insulation
No full textExperimental analysis of flanking transmission of different connection systems for CLT panels
Full text linkThis paper presents the first results of the flanksound project, a study promoted by Rotho Blaas srl regarding flanking transmission between CLT panels jointed with different connection systems. The vibration reduction index Kij is evaluated according to the EN ISO 10848 standard by measuring the velocity level difference between CLT panels. The performance of the X-RAD connection system is compared to the performance of a traditional connection system made of shear angle bracket and hold-down, both the configurations being tested with and without a resilient material placed between the construction elements. Concerning the traditional system, the influence of the difference sizes and types of fasteners - including the method of nailing or screwing - was also evaluated. The results of the measurements exposed in this work will hopefully contribute to the development of the acoustic design of timber buildings by providing a solid database of Kij values, which can be used to forecast the acoustic performance of the building according to the prediction models proposed in EN 12354-1
Analysis of acoustical behavior of bare cross laminated timber floors for the evaluation of the improvement of impact sound insulation
No full textThe estimation of impact sound insulation of horizontal partitions, evaluated from the performance of basic components using EN 12354-2 Standard, do not actually provides satisfactory results when applied to the floors realized with cross laminated timber (CLT) elements. Among the possible reasons of this limited correspondence between predicted and measured impact noise values, one of the most interesting is the difficult to correlate the reduction of the impact sound pressure level of the floor covering, measured in laboratory on a concrete slab, with the actual behavior on a bare CLT floor. In this paper the results of a laboratory evaluations independently managed by different researchers on similar CLT structures is reported. The purpose of this study is to identify an empirical spectrum of the normalized impact sound pressure level of a reference floor realized based on CLT technology, in
order to provide an useful and simple tool for estimate the noise insulation performances for this type of building element
Misure di laboratorio dell'isolamento al calpestio di massetti galleggianti su solai in CLT
No full textLa caratterizzazione acustica dei massetti galleggianti viene normalmente eseguita in laboratorio su di un solaio di riferimento in cemento armato, secondo le norme della serie ISO 10140 e non esistono dati di questi massetti su solai in CLT. L’articolo presenta i risultati di uno studio, in laboratorio, compiuto su di un solaio in legno sul quale sono stati posti in opera 15 differenti combinazioni di strati resilienti e massetti a secco o in sabbia e cemento. Si è indagato anche sull’effetto di diversi sottofondi alleggeriti. Sono stati inoltre presi in considerazione anche i controsoffitti appesi o vincolati all’intradosso del solaio.
Allo stesso tempo si è cercato di trovare una relazione sperimentale che estenda l’efficacia della relazione di Cremer anche al di sopra dei 1000 Hz, tale relazione infatti, lega il potere fonoisolante R dei solai al livello di calpestio normalizzato Ln. L’obiettivo è quello contribuire al miglioramento delle formule previsionali da utilizzare su strutture leggere, come il CLT, che non possono essere considerate infinitamente rigide come le strutture edilizie comunemente utilizzate
Vibration reduction index improvement by adding resilient strips: influence of junction properties
No full textResilient strips can be used to decrease the structural transmission in junctions and thus limit the
flanking sound transmission in buildings. In the standard ISO 12354-1, the efficiency of a resilient
strip is characterized by the vibration reduction index improvement. To evaluate the vibration
reduction improvement, a standardized measurement method is needed. However, the vibration
reduction improvement is not an intrinsic material parameter of the resilient strip and can depend
on the mounting conditions and junction geometry. In this paper, the vibration reduction index
improvement is evaluated by means of numerical simulations carried out with a statistical model
for junctions with resilient strips. The model was first validated by laboratory measurements. While
the influence of the junction type (L, T or X) and transmission path (straight on or around the corner)
is limited, the influence of the plate properties (mass and bending stiffness) cannot be neglected, with
differences in vibration reduction improvement of up to 20 dB
Influence of dimensional and connection characteristics of CLT building elements on predictive calculations
No full textThe ISO 12354-1 standard provides different calculation methods for evaluating lateral transmission depending on the vibroacoustic behavior of building structures; the standard classifies them into types A and B depending on whether the structural reverberation time of the considered element depends or not on the connecting elements. Although some construction elements are composed of the same material, they can belong to the first or second type, according to the technology of assembly or installation. CLT panels, generally belonging to type A, may sometimes behave as type B elements. This study deals with some of these cases through calculation examples based on experimental data collected on a real-scale building mockup
ETICS measurements and prediction - Verification and validation of a predictive model for the improvement of airborne sound insulation of thick external linings
No full textThe increasing demand of the reduction of carbon emissions and the consumption of energy
resources due to the construction sector leads to the concept of Zero-Energy buildings. It is
therefore crucial ensuring technical and engineering compatibility between future advancements
in energy efficiency and sound insulation. The sound insulation requirements for residential
buildings are mandatory in Italian Regulations, tested on-site after construction completion. A
noteworthy challenge is the potential synergy between specifications for energy efficiency and
sound insulation properties in building materials.
This paper deals with the validation of the prediction model for the improvement of airborne
sound insulation due to thick external linings, particularly materials used in ETICS (External
Thermal Insulation System), based on mechanical properties of involved materials. Standard ISO
9052-1 for the determination of dynamic stiffness is intended for materials used under floating
floors in dwellings. However, based on the methods of this standard, it is possible to perform
measurements (with both hammer and shaker) even on thick linings materials and use the results
for the implementation of computational models for the predictions of improvement of sound
reduction index, as a function of frequency, with good accuracy
Optimising the mechanical characterisation of a resilient interlayer for the use in timber construction
No full textResilient interlayers are used in the field of building acoustics to reduce the transmission of vibrations through the flanking transmission paths. To this end, EPDM rubber or polyurethane strips are often used as dampers and therefore a complete mechanical characterisation for these materials is required. Most of the time, the mechanical characterisation has been related to the use as damping materials to be used in "standardised" application, such as industry. This paper reports the mechanical characterisation of an extruded polyurethane strip to be used in timber buildings. The mechanical characterisation of the strip was conducted according to standard tests (tensile, compression) on macro samples as well as using the DMA in tensile and shear mode, over a wide temperature range. The stress strain relation in compression was evaluated loading the sample with different boundary conditions in order to take into account the friction provided by different supports. Steel plates, timber lamellas and the "ideal" situation without friction were tested, pointing out the peculiar characteristics of the material when used as interlayer in CLT buildings. Considerations are made relative to the extraction of the E modulus over different ranges and related to the real on-site application of the loads that might render necessary an insight into the definition of the elastic properties of such materials
Analysis of acoustic behavior of bare CLT floors for the evaluation of impact sound insulation improvement
No full textEstimation 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 elemen
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