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In Situ Measured Flanking Transmission in Light Weight Timber Houses with Elastic Flanking Isolators

https://research.thinkwood.com/en/permalink/catalogue231
Year of Publication
2013
Topic
Acoustics and Vibration
Material
CLT (Cross-Laminated Timber)
Application
Floors
Wood Building Systems
Author
Ågren, Anders
Ljunggren, Fredrik
Organization
Inter-noise
Year of Publication
2013
Country of Publication
Austria
Format
Conference Paper
Material
CLT (Cross-Laminated Timber)
Application
Floors
Wood Building Systems
Topic
Acoustics and Vibration
Keywords
Modules
Prefabrication
Sound Insulation
Elastomer Isolators
Language
English
Conference
Inter-noise 2013
Research Status
Complete
Notes
September 15-18, 2013, Innsbruck, Austria
Summary
There is a strong trend to industrially produce multi-storey light weight timber based houses. This concept allows the buildings to be manufactured to a more or less prefabricated extent. Most common types are volume/room modules or flat wall and floor modules. When assembling the modules at the building site, elastomer isolators are used in several constructions to reduce flanking transmission. The sound insulation demands in the Nordic countries are relatively high and therefore the flanking transmission must be well controlled, where elastomer isolators are an alternative. Decoupled radiation isolated walls is another. There are though no working studies or mathematical models of the performance of these isolators. They are only treated as simple mass-springs systems that operate vertically, i.e. one degree of freedom. In this paper there is an analysis of experimentally data of the structure borne sound isolating performance of elastomer isolators that are separating an excited floor from receiving walls. The performance dependence of structure type is also presented. An empirically based regression model of the vibration level difference is derived. The model is based on measurements of six elastomer field installations, which are compared to five comparable installations without elastomers. A goal is that the model can be used for input in future SEN prediction models for modeling of sound insulation.
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Sound Insulation Performance of Cross Laminated Timber Building Systems

https://research.thinkwood.com/en/permalink/catalogue342
Year of Publication
2013
Topic
Acoustics and Vibration
Material
CLT (Cross-Laminated Timber)
Application
Wood Building Systems
Author
Schoenwald, Stefan
Zeitler, Berndt
Sabourin, Ivan
King, Frances
Organization
Inter-noise
Year of Publication
2013
Country of Publication
Austria
Format
Conference Paper
Material
CLT (Cross-Laminated Timber)
Application
Wood Building Systems
Topic
Acoustics and Vibration
Keywords
Airborne Sound Insulation
Acoustic Performance
Language
English
Conference
Inter-noise 2013
Research Status
Complete
Notes
September 15-18, 2013, Innsbruck, Austria
Summary
In recent years Cross Laminated Timber (CLT) was introduced as an emerging building system in the North American market. CLT elements consist of multiple layers of wooden beams that are laid-out cross-wise and laminated together to form solid wood panels for floors and walls. As part of a multi-disciplinary research project a comprehensive study was conducted on the impact and airborne sound insulation of this type of elements in order to create a data base that allows building designers to predict the acoustic performance of CLT systems. Parametric studies were carried out on the direct impact airborne sound insulation of CLT floor assemblies (with/ without various floor topping and gypsum board ceiling variants), on the direct airborne sound insulation of CLT walls (with/without gypsum board linings), as well as on the structure-borne sound transmission on a series of CLT building junctions. The results were then used as input data for predictions of the apparent impact and airborne sound insulation in real CLT buildings using the ISO 15712 (EN12354) framework that was originally developed for concrete and masonry buildings. The paper presents the prediction approach as well as results of prediction and measurement series for apparent impact and airborne sound insulation.
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Experimental Evaluations of Material Damping in Timber Beams of Structural Dimensions

https://research.thinkwood.com/en/permalink/catalogue574
Year of Publication
2013
Topic
Acoustics and Vibration
Material
Glulam (Glue-Laminated Timber)
Application
Floors
Author
Labonnote, Nathalie
Rønnquist, Anders
Arne Malo, Kjell
Publisher
Springer Berlin Heidelberg
Year of Publication
2013
Country of Publication
Germany
Format
Journal Article
Material
Glulam (Glue-Laminated Timber)
Application
Floors
Topic
Acoustics and Vibration
Keywords
Damping
Flexural Vibrations
Language
English
Research Status
Complete
Series
Wood Science and Technology
Summary
Understanding the inherent damping mechanisms of floor vibrations has become a matter of increasing importance following the development of new composite floor layouts and increased span. The present study focuses on the evaluation of material damping in timber beam specimens with dimensions that are typical of common timber floor structures. Using the impact test method, 11 solid wood beams and 11 glulam beams made out of Norway Spruce (Picea abies) were subjected to flexural vibrations. The tests involved different spans and orientations. A total of 420 material damping evaluations were performed, and the results are presented as mean values for each configuration along with important statistical indicators to quantify their reliability. The consistency of the experimental method was validated with respect to repeatability and reproducibility. General trends found an increasing damping ratio for higher modes, shorter spans, and edgewise orientations. It is concluded from the results that material damping of timber beams of structural dimensions is governed by shear deformation, which can be expressed more conveniently with respect to the specific mode shape and its derivatives.
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Impedance Characteristics in Wooden Frames Structure Using Large Dimension Glued Laminated Timber

https://research.thinkwood.com/en/permalink/catalogue994
Year of Publication
2013
Topic
Acoustics and Vibration
Material
Glulam (Glue-Laminated Timber)
Application
Floors
Author
Yoda, Takuya
Inoue, Katsuo
Tomita, Ryuta
Okura, Yasuhiko
Organization
Architectural Institute of Japan
Year of Publication
2013
Country of Publication
Japan
Format
Journal Article
Material
Glulam (Glue-Laminated Timber)
Application
Floors
Topic
Acoustics and Vibration
Keywords
Impact Sound
Language
Japanese
Research Status
Complete
Summary
Recent years have witnessed an increased use of glued timber products in construction, due to their highlights in versatility and sustainability. It is therefore a demanding necessity to develop non-destructive integrity assessment methods for structural health monitoring of timber constructions, both during production and utilization. Particularly, the integrity and load bearing capacity of the glue line need to be tested. Air coupled ultrasound (ACU) is a novel non-destructive method which is well suited for this purpose. The advantages with respect to traditional ultrasonic contact techniques are phenomenal reproducibility and unlimited scanning capabilities, together with full preservation of the properties of the inspected object. As part of an on-going project in the Swiss Federal Laboratories for Materials Testing and Research (Empa) together with the Laboratory for Wood Physics and Non-Destructive Testing Methods of ETH Zuerich, experiments were performed in samples consisting of two layers of glued laminated timber with artificially introduced delaminations. First, the main ultrasound propagation phenomena were modelled with dedicated analytical calculations and numerical simulations. Next the samples were scanned with a precise mechanical system and a Normal Transmission Mode setup and the ACU waveforms were digitized for each scanned position. A specific amplitude tracking algorithm together with a self-calibration procedure applied to the ultrasonic images were used to compensate for ultrasonic amplitude variations induced by wood heterogeneity. The mean amplitude variations in the orthotropic R-T plane and in the L axis were of 10 and 5 dB respectively. After an appropriate wood heterogeneity correction the uncertainty in the R-T plane was reduced down to 4 dB. Adhesion defects were reliably assessed for the investigated samples, as well in situations where adhesive was present in the glue line but no bonding existed between timber lamellas (dry glue), or where the adhesive spread during the pressing in an uncontrolled way to the desired non-glued regions. The ACU results were validated with an also novel Micro Focus Computed Tomography glue line assessment method. Specific wave propagation phenomena depending on the year ring orientation with respect to the insonification direction were also discussed.
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Evaluation of Timber-Concrete Floor Performance under Occupant-Induced Vibrations using Continuous Monitoring

https://research.thinkwood.com/en/permalink/catalogue131
Year of Publication
2013
Topic
Acoustics and Vibration
Serviceability
Material
LVL (Laminated Veneer Lumber)
Timber-Concrete Composite
Application
Floors
Author
Omenzetter, Piotr
Kohli, Varun
Desgeorges, Yohann
Publisher
Scientific.net
Year of Publication
2013
Country of Publication
Switzerland
Format
Journal Article
Material
LVL (Laminated Veneer Lumber)
Timber-Concrete Composite
Application
Floors
Topic
Acoustics and Vibration
Serviceability
Keywords
Damping
Frequencies
Lightweight
Long Span
Office Buildings
Language
English
Research Status
Complete
Series
Key Engineering Materials
Summary
This paper describes the design of a system to monitor floor vibrations in an office building and an analysis of several months worth of collected data. Floors of modern office buildings are prone to occupant-induced vibrations. The contributing factors include long spans, slender and flexible designs, use of lightweight materials and low damping. As a result, resonant frequencies often fall in the range easily excited by normal footfall loading, creating potential serviceability problems due to undesirable levels of vibrations. This study investigates in-situ performance of a non-composite timber-concrete floor located in a recently constructed innovative multi-storey office building. The floor monitoring system consists of several displacement transducers to measure long-term deformations due to timber and concrete creep and three accelerometers to measure responses to walking forces, the latter being the focus of this paper. Floor response is typically complex and multimodal and the optimal accelerometer locations were decided with the help of the effective independence-driving point residue (EfI-DPR) technique. A novel approach to the EfI-DPR method proposed here uses a combinatorial search algorithm that increases the chances of obtaining the globally optimal solution. Several months worth of data collected by the monitoring system were analyzed using available industry guidelines, including ISO2631-1:1997(E), ISO10137:2007(E) and SCI Publication P354. This enabled the evaluation of the floor performance under real operating conditions.
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Serviceability of New Generation Wood Buildings: Case Study of Two Cross-Laminated Timber (CLT) Buildings

https://research.thinkwood.com/en/permalink/catalogue2644
Year of Publication
2013
Topic
Serviceability
Acoustics and Vibration
Material
CLT (Cross-Laminated Timber)
Application
Wood Building Systems
Floors
Walls
Author
Hu, Lin
Organization
FPInnovations
Year of Publication
2013
Country of Publication
Canada
Format
Report
Material
CLT (Cross-Laminated Timber)
Application
Wood Building Systems
Floors
Walls
Topic
Serviceability
Acoustics and Vibration
Keywords
Ambient Vibration Tests
Vibration Performance
Sound Insulation
Language
English
Research Status
Complete
Summary
FPInnovations launched the “Next Generation Building Systems” research program to support the expansion and diversification of wood into new markets. “Next Generation Wood Buildings” can be described as buildings that implement design and construction practices, and use innovative wood-based materials and systems beyond those defined and addressed in current building codes. As part of this program, the serviceability research focuses on addressing issues related to floor and building vibrations, sound transmission and creep. CLT is a next generation wood building material, which is a promising alternative to concrete slabs. To facilitate wood expansion into the market traditionally dominated by steel and concrete, several CLT buildings have been designed or built. Taking this opportunity, we conducted this study on two CLT buildings in the province of Quebec (i.e.,Desbiens and Chibougamau) to collect data that will form a database for the development of design provisions and installation guides for controlling vibrations and noise in CLT floors and buildings. The study also provides some information to designers and architects to strengthen their confidence in using CLT in their building projects. It is our hope that the collaboration through this study demonstrates to both designers and users of CLT buildings that if we work together, we can build good quality CLT buildings. During the construction, ambient vibration tests were conducted on the two CLT buildings to determine their natural frequencies (periods) and damping ratios. Vibration performance tests were conducted on selected CLT floors to determine their frequencies and static deflections. ASTM standard sound insulation tests were conducted on the selected CLT walls and floors in Chibougamau CLT building to develop the sound insulation solutions. After the two CLT buildings were completed, ASTM sound insulation tests were conducted in the selected units to determine the Field Sound Transmission Class (FSTC) of the finished floors and walls, and the Field Impact Insulation Class (FIIC) of the finished floors. We found that in general, the vibration performance of these two CLT buildings and their floor vibration performance are functional. The efforts made by the design engineers, the architects, and the contractors to make it happen are commendable, considering the lack of design provisions and guidelines in building codes for controlling vibrations in such innovative wood floor and buildings. The sound insulation of the selected units in Chibougamau building was very satisfactory. This confirmed that with proper design, construction, and installation of the sound insulation solutions studied in this report, CLT floors, walls and buildings can achieve very good sound insulation. Some specific recommendations for CLT building sound insulation: If flanking paths can be minimized, then it is expected that better sound insulation than what we measured on the CLT floors during the building construction will be achieved ; Increasing the stud spacing from 400mm to 600mm for the wood stud walls enhances the airborne sound insulation of the current wood stud-CLT wall assemblies tested in this study ; Decoupling ceiling from the structure frame and from the CLT floors is a significant factor for cost-effective sound insulation solutions ; Selection of solutions for FSTC and FIIC above fifty (50) for non-carpeted CLT floors will ensure the satisfaction of the majority of occupants ; Conducting subjective evaluation is useful to ensure occupants satisfaction ; For implementation of the sound insulation solutions for floating floors, it is necessary to consult wood flooring and ceramic tiles installation guides for floating the flooring.
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Dynamic Behaviour of Dowel-Type Connections Under In-Service Vibration

https://research.thinkwood.com/en/permalink/catalogue884
Year of Publication
2013
Topic
Connections
Serviceability
Acoustics and Vibration
Material
Solid-sawn Heavy Timber
Application
Frames
Beams
Author
Reynolds, Thomas
Organization
University of Bath
Year of Publication
2013
Country of Publication
United Kingdom
Format
Thesis
Material
Solid-sawn Heavy Timber
Application
Frames
Beams
Topic
Connections
Serviceability
Acoustics and Vibration
Keywords
dowel-type connections
Embedment
Nonlinear Behaviour
Time Dependent Behaviour
Energy Dissipation
Portal Frames
Language
English
Research Status
Complete
Summary
This study investigated the vibration serviceability of timber structures with dowel-type connections. It addressed the use of such connections in cutting-edge timber structures such as multi-storey buildings and long-span bridges, in which the light weight and flexibility of the structure make it possible that vibration induced by dynamic forces such as wind or footfall may cause discomfort to occupants or users of the structure, or otherwise impair its intended use. The nature of the oscillating force imposed on connections by this form of vibration was defined based on literature review and the use of established mathematical models. This allowed the appropriate cyclic load to be applied in experimental work on the most basic component of a dowel-type connection: a steel dowel embedding into a block of timber. A model for the stiffness of the timber in embedment under this cyclic load was developed based on an elastic stress function, which could then be used as the basis of a model for a complete connector. Nonlinear and time-dependent behaviour was also observed in embedment, and a simple rheological model incorporating elastic, viscoelastic and plastic elements was fitted to the measured response to cyclic load. Observations of the embedment response of the timber were then used to explain features of the behaviour of complete single- and multiple-dowel connections under cyclic load representative of in-service vibration. Complete portal frames and cantilever beams were tested under cyclic load, and a design method was derived for predicting the stiffness of such structures, using analytical equations based on the model for embedment behaviour. In each cyclic load test the energy dissipation in the specimen, which contributes to the damping in a complete structure, was measured. The analytical model was used to predict frictional energy dissipation in embedment, which was shown to make a significant contribution to damping in single-dowel connections. Based on the experimental results and analysis, several defining aspects of the dynamic response of the complete structures, such as a reduction of natural frequency with increased amplitude of applied load, were related to the observed and modelled embedment behaviour of the connections.
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Precast Timber-Concrete Composite Floor Structures for Sustainable Buildings-Experimental Verification

https://research.thinkwood.com/en/permalink/catalogue109
Year of Publication
2013
Topic
Design and Systems
Fire
Acoustics and Vibration
Material
Timber-Concrete Composite
Application
Floors
Author
Novotná, Magdalena
Fiala, Ctislav
Hájek, Petr
Year of Publication
2013
Country of Publication
Czech Republic
Format
Conference Paper
Material
Timber-Concrete Composite
Application
Floors
Topic
Design and Systems
Fire
Acoustics and Vibration
Keywords
Connections
Multi-Storey
Adhesive Connection
Language
English
Conference
Central Europe towards Sustainable Building
Research Status
Complete
Notes
June 26-28, 2013, Prague, Czech Republic
Summary
An effort to use renewable materials leads to broader utilization of timber structures also for multi-storey buildings. However, wider application of timber floor structures in multi-storey buildings is limited by lower lateral rigidity, worse acoustic and fire safety parameters in comparison to concrete floor structures. The composite floor structures based on high performance silicates and wood represent the beneficial alternative to the modern timber floor structures. Proposed timber-concrete composite floor structure benefits from lower weight of slender HPC or UHPC deck (compared to common RC slab) while improving acoustic parameters and ifre safety of the structure (compared to timber floor structure). Experimental verification proved that effective mechanical connection can be ensured by gluing. Key words: timber-concrete, high performance concrete, floor structures, experimental verification, glued connection.
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Seismic Design of Core-Walls for Multi-Storey Timber Buildings

https://research.thinkwood.com/en/permalink/catalogue134
Year of Publication
2013
Topic
Design and Systems
Seismic
Material
CLT (Cross-Laminated Timber)
Application
Shafts and Chases
Author
Dunbar, Andrew
Pampanin, Stefano
Palermo, Alessandro
Buchanan, Andrew
Year of Publication
2013
Country of Publication
New Zealand
Format
Conference Paper
Material
CLT (Cross-Laminated Timber)
Application
Shafts and Chases
Topic
Design and Systems
Seismic
Keywords
Multi-Storey
Prefabrication
Pres-Lam
Residential
Quasi-Static Loading
Energy Dissipation
U-Shaped Flexural Plates
Language
English
Conference
New Zealand Society for Earthquake Engineering Conference
Research Status
Complete
Notes
April 26-28, 2013, Wellington, New Zealand
Summary
This paper describes options for seismic design of pre-fabricated timber core-wall systems, used as stairwells and lift shafts for lateral load resistance in multi-storey timber buildings. The use of Cross-Laminated Timber (CLT) panels for multi-storey timber buildings is gaining popularity throughout the world, especially for residential construction. This paper describes the possible use of CLT core-walls for seismic resistance in open-plan commercial office buildings in New Zealand. Previous experimental testing at the University of Canterbury has been done on the in-plane behaviour of single and coupled Pres-Lam post-tensioned timber walls. However there has been very little research done on the behaviour of timber walls that are orthogonal to each other and no research into CLT walls in the post-tensioned Pres-Lam system. This paper describes the proposed test regime and design detailing of two half-scale twostorey CLT stairwells to be tested under a bi-directional quasi-static loading. The test specimens will include a half-flight stair case with landings within the stairwell. The “High seismic option” consists of post-tensioned CLT walls coupled with energy dissipating U-shaped Flexural Plates (UFP) attached between wall panels and square hollow section steel columns at the corner junctions. An alternative “Low seismic option” uses the same post-tensioned CLT panels, with no corner columns or UFPs. The panels will be connected by screws to provide a semi-rigid connection, allowing relative movement between the panels producing some level of energy dissipation.
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Wood Infill Walls in Reinforced Concrete Frame Structures: A Wood/Concrete Construction Niche

https://research.thinkwood.com/en/permalink/catalogue1591
Year of Publication
2013
Topic
Mechanical Properties
Material
Timber-Concrete Composite
Light Frame (Lumber+Panels)
Application
Hybrid Building Systems
Author
Blaylock, Jeffrey
Bartlett, Michael
Organization
University of Western Ontario
Year of Publication
2013
Country of Publication
Canada
Format
Thesis
Material
Timber-Concrete Composite
Light Frame (Lumber+Panels)
Application
Hybrid Building Systems
Topic
Mechanical Properties
Keywords
Mid-Rise
High-Rise
Deflection
Serviceability Limit States
Ultimate Limit States
Reinforced Concrete
Language
English
Research Status
Complete
Summary
This thesis investigated light-frame wood/concrete hybrid construction as part of the NSERC Strategic Network on Innovative Wood products and Building Systems (NEWBuildS). A review of eight wood/concrete niche areas identified three with potential to be used in mid- to high-rise structures. Light-frame wood structures of seven or more storeys with wood/concrete hybrid flooring seem to have little feasibility unless a concrete lateral-load-resisting system is provided and material incompatibilities are solved. Non-load-bearing light-frame wood infill walls in reinforced concrete frame structures were recognized to have potential feasibility in mid- to high-rise structures. A full-scale, single frame test apparatus was successfully designed and constructed at the Insurance Research Lab for Better Homes. The frame is statically loaded to accurately replicates realistic horizontal sway and vertical racking deformations of a typical eight storey reinforced concrete frame structure at SLS and ULS. A linear-elastic analysis of the test apparatus was generally able to predict the results during testing. The 2.4m x 4.8m (8 ft. x 16 ft.) infill wall specimen did not satisfy serviceability deflection limitations of L/360 when subjected to representative out-of-plane wind pressures of +1.44/-0.9 kPa. The out-of-plane response was not significantly affected by horizontal sway deflections of +/-7.2mm or vertical racking deflections of +9.6mm. Although a nominal 20mm gap was provided to isolate the wall from the surrounding frame, insulation foam sprayed in the gap facilitated load transfer between them.
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10 records – page 1 of 1.