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Competitive wooden floor systems - Multi-objective optimisation based on acoustics improvement

English title Competitive wooden floor systems - Multi-objective optimisation based on acoustics improvement
Applicant Krajci Lubos
Number 136683
Funding scheme NRP 66 Resource Wood
Research institution Soundtherm GmbH
Institution of higher education Companies/ Private Industry - FP
Main discipline Civil Engineering
Start/End 01.10.2012 - 31.12.2015
Approved amount 372'028.00
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All Disciplines (3)

Discipline
Civil Engineering
Material Sciences
Other disciplines of Environmental Sciences

Keywords (1)

ecology

Lay Summary (German)

Lead
Akustisch optimierte Deckenkonstruktion aus Hartholz In diesem Projekt entwickeln die Forschenden eine Deckenkonstruktion aus Hartholz mit verbesserter Schalldämmung im Tieftonbereich und ein Instrument zur mehrdimensionalen Optimierung dieser Konstruktion.
Lay summary

Hintergrund
Die schweizerische Holzpolitik hat sich zum Ziel gesetzt, vermehrt Hartholz im Bauwesen einzusetzen. Herausforderungen stellen sich beim Schallschutz von Holzbauten, vor allem für tiefe Frequenzen unterhalb von 100 Hertz. Schall dieser Frequenzen entsteht beim Gehen oder Springen sowie bei Heimkinos (Home Cinemas) in der Wohnung und wird von Nachbarn oft als störend empfunden. Um einen vergleichbaren Schallschutz wie im Massivbau zu erreichen, bedarf es in mehrgeschossigen Holzbauten heute spezieller Deckenaufbauten mit komplizierten Strukturen und grossen Deckenhöhen. Dadurch sind Holzbauten nur beschränkt mit Massivbauten konkurrenzfähig.
Bauprodukte müssen heute verschiedenen Anforderungen (ökonomische, ökologische und gesellschaftliche) gleichzeitig gerecht werden. Dafür bedarf es entsprechender Instrumente zur mehrdimensionalen Optimierung von Bauprodukten.

Ziel
Die Forscher werden eine Deckenkonstruktion aus Schweizer Hartholz entwickeln und als Prototyp herstellen. Diese soll im Vergleich zu bisherigen Konstruktionen eine ähnliche oder bessere Schalldämmung im Tieftonbereich erreichen und eine maximale Höhe von 0.35 Meter aufweisen. Basierend auf theoretischen Grundlagen und empirischen Berechnungen stellen die Forschenden zunächst eine Deckenkonstruktion her. An dieser untersuchen sie die einzelnen Übertragungswege des Schalls. Auf der Grundlage der gewonnenen Erkenntnisse entwickeln sie dann ein Werkzeug, um die Schallübertragung von tiefen Frequenzen zu diagnostizieren und den Schallschutz zu verbessern.

Bedeutung
Bei Projekterfolg steht dem mehrgeschossigen Holzbau ein Element zur Verfügung, um den Schallschutz zu verbessern und Hartholz im Sinne der schweizerischen Holzpolitik konkurrenzfähiger zu machen.

Direct link to Lay Summary Last update: 25.01.2013

Lay Summary (French)

Lead
Construction de planchers en bois dur à l’acoustique optimisée Les chercheurs de ce projet mettent au point une construction de planchers en bois dur présentant une insonorisation améliorée des graves et un instrument d’optimisation sur plusieurs dimensions de cette construction.
Lay summary

Contexte
La politique suisse du bois s’est fixée pour objectif d’augmenter la part du bois dur dans la construction. Un défi tout particulier est l’insonorisation des bâtiments en bois, notamment dans les fréquences graves inférieures à 100 hertz. Des sons de ces fréquences sont générés quand les occupants marchent ou sautent, ou encore par les "home cinemas" en appartement et ils incommodent souvent les voisins. Pour obtenir une insonorisation comparable à celle des constructions en dur, les bâtiments en bois à plusieurs étages requièrent des constructions spéciales intégrées aux planchers, dotées de structures complexes et de hauteurs de plafond importantes, ce qui limite leur compétitivité face aux bâtiments en dur.
Les produits de construction doivent répondre simultanément à différentes exigences (économiques, écologiques et sociétales). Ces conditions appellent des instruments adaptés capables de les optimiser à plusieurs niveaux.

But
Les chercheurs vont mettre au point une construction de plancher à partir de bois durs suisses et la réaliser comme prototype. Elle devra présenter une insonorisation dans les graves comparable ou supérieure à celle des constructions réalisées à ce jour et une hauteur de plafond maximale de 0,35 mètres. Sur la base de données théoriques et de calculs empiriques, les chercheurs commencent par construire un plancher sur lequel ils étudient en détail la propagation du son. A partir des conclusions tirées, ils développent un outil servant à diagnostiquer la diffusion du son dans les fréquences graves pour améliorer l’insonorisation.

Portée
La réussite du projet sera, pour la construction en bois de bâtiments à plusieurs étages, un facteur d’amélioration de l’insonorisation, dans l’objectif visé par la politique suisse en matière de bois de renforcer la compétitivité du bois dur.

Direct link to Lay Summary Last update: 25.01.2013

Lay Summary (English)

Lead
Acoustically optimised floor system made of hardwood In this project, researchers are developing a floor construction out of hardwood offering better acoustic insulation in the low frequency range along with an instrument for the multidimensional optimisation of this construction.
Lay summary

Background
One of the goals of Swiss policies on wood is to increase the use of hardwood in the building sector. In this context, the acoustic insulation of wooden buildings poses a challenge, particularly for frequencies below 100 Hertz. Noise at these frequencies is created by walking and jumping as well as home cinemas in flats and is often considered a disturbance by neighbours. In order to achieve an acoustic protection that is comparable with the one in concrete constructions, special floor constructions with complicated structures and thick ceilings are currently necessary in multi-storey wooden buildings. Therefore wooden buildings can only compete with concrete buildings to a limited degree.
Today's construction products need to meet a number of requirements (economic, ecological and social) at once. This calls for the development of instruments for the multidimensional optimisation of construction products.

Aim
The researchers will develop and produce as a prototype a floor system of Swiss hardwood. It should have a maximum height of 0.35 metres and provide acoustic insulation in the low-frequency range that is similar to or better than the noise protection offered by existing constructions. Based on theoretical principles and empirical calculations, the researchers will initially produce a floor construction. Subsequently, they will examine the sound transmission paths in this construction. Based on the insights gained, they will go on to develop a tool for diagnosing the transmission of low frequency sounds and improving noise protection.

Significance
If the project is successful, it will provide multi-storey wood construction with a means of improving noise protection and it will make hardwood more competitive in accordance with Swiss policies on wood.

Direct link to Lay Summary Last update: 25.01.2013

Responsible applicant and co-applicants

Employees

Name Institute

Publications

Publication
Competitive wooden floor systems - multi-objective optimization based on acoustics improvement
Mahn J Hopkins C Schanda U Krajci L (2013), Competitive wooden floor systems - multi-objective optimization based on acoustics improvement, I-INCE, I-INCE Internoise 2013 conference proceedings.
Experimentally validated finite element models for the modal response of a solid timber floor formed from dowel-connected joists
Filippoupolitis M Hopkins C Völtl R Schanda U Mahn J Krajči L, Experimentally validated finite element models for the modal response of a solid timber floor formed from dowel-connected joists, Forum Acusticum 2014 conference proceedings, Forum Acusticum 2014 conference proceedings.
Experimentally validated finite element models for the modal response of a solid timber floor formed from dowel–connected joists
Marios Filippoupolitis, Experimentally validated finite element models for the modal response of a solid timber floor formed from dowel–connected joists, Forum Acousticum Conference 2014 , Krakaw.
The Optimization of a Wooden Floor Design Based on Validated Finite Element Models
Jeffrey MAHN, The Optimization of a Wooden Floor Design Based on Validated Finite Element Models, Internoise Conference 2014, Melbourne.
Vibroacoustic finite element modelling of the low-frequency performance of a solid timber floor formed from dowel-connected joists
M. Filippoupolitis N. Ferreira C. Hopkins R. Voltl U. Schanda J. Mahn L. Krajci, Vibroacoustic finite element modelling of the low-frequency performance of a solid timber floor formed from dowel-connected joists, Internoise 2016, Hamburg, DE.

Collaboration

Group / person Country
Types of collaboration
Nägeli Holzbau Switzerland (Europe)
- Industry/business/other use-inspired collaboration
University Liverpool Great Britain and Northern Ireland (Europe)
- in-depth/constructive exchanges on approaches, methods or results
- Publication
Hochschule Rosenheim Germany (Europe)
- in-depth/constructive exchanges on approaches, methods or results
- Publication
- Research Infrastructure
- Exchange of personnel
University Canterbury Christchurch New Zealand (Oceania)
- in-depth/constructive exchanges on approaches, methods or results
- Publication
- Exchange of personnel

Awards

Title Year
Comparison of theoretical predictions of radiation efficiency with experimental measurements 2015

Abstract

The project deals with timber floors for multi storey apartment and office buildings. In addition to that the trends towards more sustainable building concepts demands that aspects of assembling and disassembling, environmental impact, economics and multifunctionality (in terms of installations included in these elements) have to be addressed within the design of floor systems in order to create solutions that are fit for the future.There are many systems for timber floors on the market. However, a lot of them fail to really compete with massive concrete floors. The two main reasons for this are:•Economic aspects and structural composition •Acoustic performance The main objective of the proposed research project is to develop and implement multifunctional timber floor systems with improved acoustical properties and a multilevel optimization approach. These floor systems should be targeting at least dimensions that lie in the range of comparable concrete floors and at the same time perform better in terms of environmental impact. The proposed solutions should be based on timber and timber hybrid systems . Regarding the timber, the possible use of Swiss hardwoods (being a type of wood that on the one hand is currently not usable for most constructions because of static deflection and on the other hand offering promising potentials in the field of acoustics because of higher mass) in such systems shall be studied and its implementation shall be forced where possible. With this project it is planned to provide timber based floor systems with improved properties in the field of acoustics, design strength and stiffness, dynamics (vibration), economy and ecology to the market. The intention is to increase the share of timber based floors within the Swiss construction market and with this to contribute to a higher wood (including hardwood) utilization in general.With constant improvement on part of the running energy consumption the environmental impact from building materials will be of increasing relative importance in buildings LCA in the future. Within the project the relevance of the environmental impact of the floor system will be assessed in relation to (equal performing) alternatives.
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