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Vibration Serviceability of Footbridges Made of the Sustainable and Eco Structural Material: Glued-Laminated Wood

https://research.thinkwood.com/en/permalink/catalogue2977
Year of Publication
2022
Topic
Acoustics and Vibration
Material
Glulam (Glue-Laminated Timber)
Author
Hawryszków, Pawel
Biliszczuk, Jan
Organization
Wroclaw University of Science and Technology
Editor
Li, Fengming
Publisher
MDPI
Year of Publication
2022
Format
Journal Article
Material
Glulam (Glue-Laminated Timber)
Topic
Acoustics and Vibration
Keywords
Footbridges
Dynamic Behaviour
In situ Measurement
Research Status
Complete
Series
Materials
Summary
In this paper, dynamic analyses of two untypical, modern footbridges made of glued-laminated timber are presented. One of them is among the longest cable-stayed bridges for pedestrians in the world, made of such a structural material. Both structures are qualified as having low sensitivity to vibrations. The results of numerical modal analysis using FEM and non-destructive experimental dynamic tests of investigated footbridges are compared. Important differences in obtained results are captured, which are identified as the positive effect in relation to design aspects. Moreover, the same in situ measurements confirm the high level of damping in footbridges made of glued-laminated wood, which is a very significant and distinguishing feature not commonly recognized. The study also calls attention to the choice of timber as an advisable material for footbridges. This is not only because of environmentally friendly and aesthetic reasons, but also due to providing highly satisfying vibration comfort for pedestrians.
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Cross-Laminated Timber Floor: Analysis of the Acoustic Properties and Radiation Efficiency

https://research.thinkwood.com/en/permalink/catalogue3018
Year of Publication
2022
Topic
Acoustics and Vibration
Material
CLT (Cross-Laminated Timber)
Application
Floors
Author
Granzotto, Nicola
Marzi, Arianna
Gasparella, Andrea
Organization
Free University of Bozen
Editor
Vasques, César M. A.
Publisher
MDPI
Year of Publication
2022
Format
Journal Article
Material
CLT (Cross-Laminated Timber)
Application
Floors
Topic
Acoustics and Vibration
Keywords
Acoustic Characterization
Sound Radiation Efficiency
Research Status
Complete
Series
Applied Sciences
Summary
Cross-Laminated Timber (CLT) is a building technology that is becoming increasingly popular due to its sustainable and eco-friendly nature, as well as its availability. Nevertheless, CLT presents some challenges, especially in terms of impact noise and airborne sound insulation. For this reason, many studies focus on the vibro-acoustic behavior of CLT building elements, to understand their performance, advantages and limitations. In this paper, a 200 mm CLT floor has been characterized in the laboratory, according to ISO standards, by three noise sources: dodecahedron, standard tapping machine and rubber ball. In order to understand the vibro-acoustic behavior of the CLT floor, measurements through the analysis of sound pressure levels and velocity levels, measured by dedicated sensors, were performed. Analysis was carried out in order to understand what is prescribed by the prediction methods available in the literature and by the simulation software. Then, a specific prediction law for the CLT floor under investigation was derived. Finally, an analysis on sound radiation index is provided to complete the vibro-acoustic study.
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Experimental modal analysis of a cross-laminated timber slab

https://research.thinkwood.com/en/permalink/catalogue3009
Year of Publication
2022
Topic
Acoustics and Vibration
Material
CLT (Cross-Laminated Timber)
Author
Kawrza, M.
Furtmüller, T.
Adam, C.
Maderebner, R.
Organization
University of Innsbruck
Publisher
Elsevier
Year of Publication
2022
Format
Conference Paper
Material
CLT (Cross-Laminated Timber)
Topic
Acoustics and Vibration
Keywords
Experimental Modal Analysis
Complex Mode Shapes
Modal Parameter Estimation
Conference
37th Danubia Adria Symposium on Advances in Experimental Mechanics
Research Status
Complete
Series
Materials Today: Proceedings
Summary
This paper presents the results of an investigation of the dynamic response of a point-supported cross-laminated timber (CLT) slab without joists with a column grid of 5.0 × 5.0 m and overall dimensions of 16.0 × 11.0 × 0.2 m. The results are based on a detailed experimental modal analysis, identifying seven modes from the dynamic response of 651 measurement points, including natural frequencies, mode shapes and damping ratios. These modal parameters exhibit a time variance that is due to environmental influences during the measurement period of two days. As a result of this disturbance effect, the determined mode shapes have a non-negligible imaginary part, which is eliminated by correcting each of the 73 measurements individually. The findings presented provide in-depth insight into the dynamic behavior of the large-scale CLT structure with point supports realized with a novel steel connector.
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U.S. Mass Timber Floor Vibration Design Guide

https://research.thinkwood.com/en/permalink/catalogue2874
Year of Publication
2021
Topic
Acoustics and Vibration
Material
CLT (Cross-Laminated Timber)
NLT (Nail-Laminated Timber)
DLT (Dowel Laminated Timber)
Glulam (Glue-Laminated Timber)
Application
Floors
Organization
WoodWorks
Year of Publication
2021
Format
Book/Guide
Material
CLT (Cross-Laminated Timber)
NLT (Nail-Laminated Timber)
DLT (Dowel Laminated Timber)
Glulam (Glue-Laminated Timber)
Application
Floors
Topic
Acoustics and Vibration
Keywords
Floor Vibration
Vibration Design Methods
Finite Element Modeling
Research Status
Complete
Summary
The scope of this guide focuses on the design of mass timber floor systems to limit human-induced vibration. The primary performance goal is to help designers achieve a low probability of adverse comment regarding floor vibrations in a manner consistent with the vibration design guides for steel and concrete systems. This includes excitation primarily from human walking as observed by other people in the building. Some treatment of design for sensitive equipment in response to human walking is also discussed. This design guide covers the range of currently available mass timber panels, including cross-laminated timber (CLT) manufactured from either solid sawn or structural composite lumber (SCL) laminations, nail-laminated timber (NLT), dowel laminated timber (DLT) and glue-laminated timber (GLT), as well as their support framework of timber beams. The target user of this guide is a design professional with working knowledge of mass timber structural design and some background knowledge of structural dynamics as related to floor vibrations. It may be particularly useful to design engineers with limited experience with vibration analysis, experienced multi-material engineers familiar with vibration analysis but unfamiliar with mass timber vibration, and applications engineers assisting manufacturers in the development of solutions and proposals for projects.
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From Canada to the World: FPInnovations' Three-Generation Floor Vibration Research and Code Implementation

https://research.thinkwood.com/en/permalink/catalogue2826
Year of Publication
2021
Topic
Acoustics and Vibration
Material
CLT (Cross-Laminated Timber)
Light Frame (Lumber+Panels)
Application
Floors
Author
Hu, Lin
Cuerrier-Auclair, Samuel
Qian, Cheng
Dale, Angela
Organization
FPInnovations
Year of Publication
2021
Format
Report
Material
CLT (Cross-Laminated Timber)
Light Frame (Lumber+Panels)
Application
Floors
Topic
Acoustics and Vibration
Keywords
Lumber Joists
Engineered Wood Joists
Mass Timber
Floor Vibration-controlled Design Method
CSA 086
National Building Code of Canada
Research Status
Complete
Series
InfoNote
Summary
FPInnovations’involvement in various codes and standards technical committees aims to monitor, contributeor propose changes for improvement as well as to create new standards to include new wood products and systems based on knowledge developed from FPInnovations’ research activities. Involvement also allows FPInnovations to be aware of any potential changes to codes and standards and to recognize and address threats and opportunities for wood use. Codes and standards exist to protect consumers but are written to reflect the current practices and knowledge based on a consensus agreement by committee members. FPInnovations’ involvement in codes and standards committees helps to align the coming changes with new wood products. This InfoNote reports on FPInnovations’ contribution to the floor vibration-control design methods on codes and standards implementation and research.
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Performance of midply shear wall

https://research.thinkwood.com/en/permalink/catalogue3037
Year of Publication
2022
Topic
Mechanical Properties
Fire
Acoustics and Vibration
Application
Shear Walls
Author
Ni, Chui
Dagenais, Christian
Qian, Cheng
Hu, Lin
Organization
FPInnovations
Year of Publication
2022
Format
Report
Application
Shear Walls
Topic
Mechanical Properties
Fire
Acoustics and Vibration
Keywords
Midply Shear Wall
Structural Performance
Fire Performance
Acoustic Performance
Research Status
Complete
Summary
Midply shear wall, which was originally developed by researchers at Forintek Canada Corp. (predecessor of FPInnovations) and the University of British Columbia, is a high-capacity wood-frame shear wall system that is suitable for high wind and seismic loadings. Its superior seismic performance was demonstrated in a full-scale earthquake simulation test of a 6-storey wood-frame building in Japan (Peietal.,2010). Midply shear wall, however, had limited applications due to its low resistance to vertical load and difficulty to accommodate electrical and plumbing services. For broader applications of Midply shearwall, these limitations needed to be addressed. In collaboration with APA–The Engineered Wood Association and the American Wood Council (AWC), a new framing arrangement was designed to increase the vertical load resistance of Midply shearwalls and make it easier to accommodate electrical and plumbing services. Consequently, structural, fire and acoustic tests have been conducted to evaluate various performance attributes of Midply shear wall with the new framing configuration. This InfoNote provides a summary of the structural, fire and acoustic performance of Midply shearwalls from the tests.
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Reduced and test-data correlated FE-models of a large timber truss with dowel-type connections aimed for dynamic analyses at serviceability level

https://research.thinkwood.com/en/permalink/catalogue3004
Year of Publication
2022
Topic
Mechanical Properties
Serviceability
Acoustics and Vibration
Material
Glulam (Glue-Laminated Timber)
Application
Trusses
Author
Landel, Pierre
Linderholt, Andreas
Organization
RISE Research Institutes of Sweden
Linnaeus University
Publisher
Elsevier
Year of Publication
2022
Format
Journal Article
Material
Glulam (Glue-Laminated Timber)
Application
Trusses
Topic
Mechanical Properties
Serviceability
Acoustics and Vibration
Keywords
Tall Timber Structures
Mechanical Connection
Dowel-type Fastener
Wind-induced Vibration
Modal Testing Properties
Connection Stiffness
FE-Model Reduction
Research Status
Complete
Series
Engineering Structures
Summary
The rise of wood buildings in the skylines of cities forces structural dynamic and timber experts to team up to solve one of the new civil-engineering challenges, namely comfort at the higher levels, in light weight buildings, with respect to wind-induced vibrations. Large laminated timber structures with mechanical joints are exposed to turbulent horizontal excitation with most of the wind energy blowing around the lowest resonance frequencies of 50 to 150 m tall buildings. Good knowledge of the spatial distribution of mass, stiffness and damping is needed to predict and mitigate the sway in lighter, flexible buildings. This paper presents vibration tests and reductions of a detailed FE-model of a truss with dowel-type connections leading to models that will be useful for structural engineers. The models also enable further investigations about the parameters of the slotted-in steel plates and dowels connections governing the dynamical response of timber trusses.
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Predicting the Human-Induced Vibration of Cross Laminated Timber Floor Under Multi-Person Loadings

https://research.thinkwood.com/en/permalink/catalogue2701
Year of Publication
2021
Topic
Acoustics and Vibration
Material
CLT (Cross-Laminated Timber)
Application
Floors
Author
Wang, Chang
Chang, Wen-Shao
Yan, Weiming
Huang, Haoyu
Publisher
ScienceDirect
Year of Publication
2021
Format
Journal Article
Material
CLT (Cross-Laminated Timber)
Application
Floors
Topic
Acoustics and Vibration
Keywords
Human-Induced Vibration
Multi-Person Loadings
Numerical Modelling
Research Status
Complete
Series
Structures
Summary
The vibration of cross laminated timber (CLT) floor is closely related to human-induced loadings. However, research and prediction approaches regarding human-induced vibration of the CLT floor have been mostly limited to a single-person excitation condition. This paper presents new prediction approaches to the vibration response of the CLT floor under multi-person loadings. The effect of multi-person loadings on the vibration performance of a CLT floor was investigated through numerical modelling, experimental testing and analytical investigation. A finite element model was developed through a computational software to perform an accurate analysis of human-induced loadings. An analytical model was established to predict human-induced vibration of the CLT floor under multi-person loadings. Experimental tests were conducted to validate the numerical modelling. Results of both numerical modelling and experimental testing showed that the vibration performance of the CLT floor under multi-person loadings was almost double that under single-person loadings. Thus, multi-person activities are more likely to cause the occupants feelings of discomfort. A method for predicting the human-induced vibration of the CLT floor under multi-person loadings was then developed. The measured response, numerical modelled response, and predicted response were compared using an existing design metric, vibration dose value (VDV). The results were largely consistent. It is therefore concluded that the proposed prediction method will enable engineers to design timber floor systems that consider multi-person loadings.
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In-situ performance testing of a four storey CLT building in Vancouver. Building vibration and sound insulation

https://research.thinkwood.com/en/permalink/catalogue2909
Year of Publication
2021
Topic
Acoustics and Vibration
Material
CLT (Cross-Laminated Timber)
Application
Floors
Author
Sadegh-Mazloomi, Mohammad
Organization
FPInnovations
Year of Publication
2021
Format
Report
Material
CLT (Cross-Laminated Timber)
Application
Floors
Topic
Acoustics and Vibration
Keywords
Ambient Vibration Testing
Acoustic Testing
Insulation
Research Status
Complete
Summary
FPInnovations has been conducting a series of field testing on wood mid-rise and tall wood buildings, including this 4-story mass timber building in Vancouver, to measure their dynamic performance. The general objectives of the field measurements of the building wind-induced vibrations and sound insulation performance are to develop improved knowledge and assemble a database of wind-induced vibration and sound insulation performance of mid-rise and tall-wood buildings. Ambient vibration and ASTM acoustic testing were performed to measure the dynamic performance of the building including the building natural frequencies, damping ratios and mode shapes. It was found that the measured first natural frequency and damping ratio of this building are overall similar to those measured from other 4-storey buildings that have exhibited good wind-induced vibration performance. The measured apparent impact insulation performance (AIIC) of 58 is considered as a satisfactory sound insulation performance indicator according to FPInnovations’ field experience about occupant satisfaction. It is believed that the test results will help the designers to obtain insight into the construction details of the building and the correlations between the details and the final performances in terms of building dynamic and sound insulation performance. Furthermore, the test results provided reliable data on the vibration and the sound insulation performance of the selected floor assemblies. The measured AIIC, building natural frequencies, and damping ratios can provide technical reference to architects and engineers to verify their designs and the design tools used.
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In-Situ performance testing of a six-storey wood-frame building in Victoria: building vibration, and sound insulation

https://research.thinkwood.com/en/permalink/catalogue3036
Year of Publication
2021
Topic
Acoustics and Vibration
Application
Wood Building Systems
Author
Mazloomi, Mohammad-Sadegh
Organization
FPInnovations
Year of Publication
2021
Format
Report
Application
Wood Building Systems
Topic
Acoustics and Vibration
Keywords
Wood-Frame Building
Ambient Vibration Testing
Acoustic Testing
Apparent Sound Transmission Class
Apparent Impact Insulation Performance
Natural Frequency
Damping Ratio
Research Status
Complete
Summary
FPInnovations has been conducting a series of field testing on mid-rise and tall-wood buildings including this 6-storey wood-frame building in Victoria to measure their dynamic performance.The general objectives of the field measurements of the building wind-induced vibrations and sound insulation performance are: to develop improved knowledge and assemble a database of wind-induced vibration and sound insulation performance of mid-rise and tall-wood buildings, especially prefabricated wood construction; to verify the application of the NBCC design method for wind-induced vibration control for wood construction; and to verify the design tools used by designers for controlling the wind-induced vibrations and noise in mid-rise and tall-wood buildings.
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A review of the thermal and acoustic properties of materials for timber building construction

https://research.thinkwood.com/en/permalink/catalogue3111
Year of Publication
2021
Topic
Acoustics and Vibration
Author
Caniato, Marco
Marzi, Arianna
Silva, Sandra Monteiro da
Gasparella, Andrea
Organization
Piazza Università
University of Minho
Publisher
Elsevier
Year of Publication
2021
Format
Journal Article
Topic
Acoustics and Vibration
Keywords
Thermal
Simulation
Material
Research Status
Complete
Series
Journal of Building Engineering
Summary
Nowadays, there is a vast need to calculate performances of timber constructions. Usually, simulations are implemented to predict buildings elements final performances. Here, the thermal and acoustic parameters necessary to simulate the performances of timber buildings elements are investigated. These data are need as input information for simulations. Anyway, at present literature does not provide a unified view and it lacks an overall vision. Furthermore, in this paper the material properties used as starting points for simulation methods are collected, compared and catalogued in order to produce a complete dataset, useable for acoustic and thermal simulation in timber buildings.
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Improved low-frequency performance of cross-laminated timber floor panels by informed material selection

https://research.thinkwood.com/en/permalink/catalogue2961
Year of Publication
2021
Topic
Acoustics and Vibration
Material
CLT (Cross-Laminated Timber)
Application
Floors
Author
Persson, Peter
Flodén, Ola
Danielsson, Henrik
Peplow, Andrew
Andersen, Lars Vabbersgaard
Organization
Lund University
Aarhus University
Publisher
Elsevier
Year of Publication
2021
Format
Journal Article
Material
CLT (Cross-Laminated Timber)
Application
Floors
Topic
Acoustics and Vibration
Keywords
Vibroacoustic Response
Floor Vibration
Wood Species
Strength Class
Finite Element Method (FEM)
Research Status
Complete
Series
Applied Acoustics
Summary
The paper demonstrates improved structural low-frequency vibroacoustic performance of cross-laminated timber (CLT) floor panels by informed selection of the wood material. The use of wood species and strength classes that are not traditionally assigned to CLT panels was investigated in order to study their influence on dynamic characteristics and vibroacoustic response metrics. The potential of each of the orthotropic material properties to alternate the vibration response was examined to determine the governing parameters of the low-frequency vibroacoustic performance. The effects on transfer mobility response functions, and eigenfrequencies and mode shapes were used for a rigorous performance study of the panels. It was found that using laminations with stiffness properties typical for hardwoods ash, beech, and birch can significantly improve the performance of a CLT floor panel, and they outperform laminations of typical softwood strength classes.
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Model updating of seven-storey cross-laminated timber building designed on frequency-response-functions-based modal testing

https://research.thinkwood.com/en/permalink/catalogue2866
Year of Publication
2021
Topic
Acoustics and Vibration
Material
CLT (Cross-Laminated Timber)
Application
Wood Building Systems
Author
Kurent, Blaž
Brank, Boštjan
Ao, Wai Kei
Organization
University of Ljubljana
University of Exeter
Publisher
Taylor&Francis Group
Year of Publication
2021
Format
Journal Article
Material
CLT (Cross-Laminated Timber)
Application
Wood Building Systems
Topic
Acoustics and Vibration
Keywords
Tall Timber Buildings
Dynamic Service Loading
Forced Vibration Tests
Modal Properties
Research Status
Complete
Series
Structure and Infrastructure Engineering
Summary
Based on the experimental estimation of the key dynamic properties of a seven-storey building made entirely of cross-laminated timber (CLT) panels, the finite element (FE) model updating was performed. The dynamic properties were obtained from an input-output full-scale modal testing of the building in operation. The chosen parameters for the FE model updating allowed the consideration of the timber connections in a smeared sense. This approach led to an excellent match between the first six experimental and numerical modes of vibrations, despite spatial aliasing. Moreover, it allowed, together with the sensitivity analysis, to estimate the stiffness (affected by the connections) of the building structural elements. Thus, the study provides an insight into the as-built stiffness and modal properties of tall CLT building. This is valuable because of the currently limited knowledge about the dynamics of tall timber buildings under service loadings, especially because their design is predominantly governed by the wind-generated vibrations.
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Effects of interconnections between timber floor elements: dynamic and static evaluations of structural scale tests

https://research.thinkwood.com/en/permalink/catalogue3113
Year of Publication
2021
Topic
Acoustics and Vibration
Material
Glulam (Glue-Laminated Timber)
Application
Floors
Author
Nesheim, Sveinung
Malo, Kjell Arne
Labonnote, Nathalie
Organization
Norwegian University of Science and Technology
Publisher
Springer
Year of Publication
2021
Format
Journal Article
Material
Glulam (Glue-Laminated Timber)
Application
Floors
Topic
Acoustics and Vibration
Keywords
Closed Hollow Section
Interconnection
Cyclic Loading Experiments
Point-load Deflection
Vibration Serviceability Performance
Research Status
Complete
Series
European Journal of Wood and Wood Products
Summary
Long-span timber floor elements increase the flexibility of a building and exhibit a significant market potential. Timber floor elements are endeavouring to fulfil this potential, but building projects employing long-span timber floors have encountered drawbacks. High costs and vibration performance are challenging, and the timber industry is under substantial pressure to find attractive solutions for building components with otherwise favourable environmental features. Only a few existing studies have investigated serviceability sensitivity in relation to timber floor connections. Interconnections are inexpensive to produce and install and may offer a resource-efficient approach to improving serviceability performance. In the present study, the effect of interconnections is investigated in a full-scale structural test. Floor elements positioned in different configurations have been tested for static and dynamic performance using different types of interconnections. The observed effects of interconnection types vary according to the configuration and direction of mode shapes, and are assessed in terms of shift in frequency, damping and resonant energy. These can all be utilised in combination with observed differences in the deflection parameter. The present work demonstrates that connections between timber elements have significant effects on timber floor serviceability and may offer interesting solutions to improve the vibration performance of long-span timber floors.
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The Influence of Floor Layering on Airborne Sound Insulation and Impact Noise Reduction: A Study on Cross Laminated Timber (CLT) Structures

https://research.thinkwood.com/en/permalink/catalogue2894
Year of Publication
2021
Topic
Acoustics and Vibration
Material
CLT (Cross-Laminated Timber)
Application
Floors
Author
Bettarello, Federica
Gasparella, Andrea
Caniato, Marco
Organization
University of Trieste
Free University of Bozen
Editor
Piana, Edoardo
Bonfiglio, Paolo
Rychtarikova, Monika
Publisher
MDPI
Year of Publication
2021
Format
Journal Article
Material
CLT (Cross-Laminated Timber)
Application
Floors
Topic
Acoustics and Vibration
Keywords
Impact Noise Transmission
Sound Insulation
Rubber Ball
Tapping Machine
Sustainable
Research Status
Complete
Series
Applied Sciences
Summary
The use of timber constructions recently increased. In particular, Cross Laminated Timber floors are often used in multi-story buildings. The development of standardization processes, product testing, design of details and joints, the speed of construction, and the advantages of eco-sustainability are the main reasons why these structures play a paramount role on the international building scene. However, for further developments, it is essential to investigate sound insulation properties, in order to meet the requirements of indoor comfort and comply with current building regulations. This work presents the results obtained by in field measurements developed using different sound sources (tapping machine, impact rubber ball, and airborne dodecahedral speaker) on Cross Laminated Timber floors, changing different sound insulation layering (suspended ceiling and floating floors). Results clearly show that the influence on noise reduction caused by different layering stimulated by diverse noise source is not constant and furthermore that no available analytical model is able to correctly predict Cross Laminated Timber floors acoustic performances.
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A Study on the Sound Insulation Performance of Cross-laminated Timber

https://research.thinkwood.com/en/permalink/catalogue2837
Year of Publication
2021
Topic
Acoustics and Vibration
Material
CLT (Cross-Laminated Timber)
Application
Walls
Author
Lin, Jui-Yen
Yang, Chieh-Ting
Tsay, Yaw-Shyan
Organization
National Cheng Kung University
Editor
Savaidis, Georgios
Publisher
MDPI
Year of Publication
2021
Format
Journal Article
Material
CLT (Cross-Laminated Timber)
Application
Walls
Topic
Acoustics and Vibration
Keywords
Transmission Loss
Acoustic Performance
Predictive Model
Numerical Simulation
Research Status
Complete
Series
Materials
Summary
Cross-laminated Timber (CLT) has become an emerging board material of wood construction that is strong enough to sustain a high-rise building. However, many wooden congregate housing units overseas that utilize CLT have poor sound environments because the low mass of such wood influences sound insulation performance. In this research, we explored the effect of different CLT walls on sound insulation performance and integrated applicable sound insulation simulation tools to simplify the process of designing a CLT wall structure. This research aimed at a double wall and CLT combined with a gypsum board as the research object. The sound insulation performance test was carried out in a laboratory, while the sound insulation performance of the structure was predicted through simulation tools and prediction models and then compared with the measured values to verify the applicability of the simulation tool. The CLT with a double wall and CLT with gypsum board (CLT + GB) achieved Rw of 50 dB. The numerical simulation had better prediction performance than INSUL at the double wall, while the double wall with cavity structure was close to the measured result via mass law calculation. The INSUL-predicted CLT with a gypsum board at 500 Hz~3150 Hz was close to the measured value.
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Airborne and impact sound performance of modern lightweight timber buildings in the Australian construction industry

https://research.thinkwood.com/en/permalink/catalogue2948
Year of Publication
2021
Topic
Acoustics and Vibration
Material
CLT (Cross-Laminated Timber)
Application
Wood Building Systems
Author
Jayalath, Amitha
Navaratnam, Satheeskumar
Gunawardena, Tharaka
Mendis, Priyan
Aye, Lu
Organization
The University of Melbourne
RMIT University
Publisher
Elsevier
Year of Publication
2021
Format
Journal Article
Material
CLT (Cross-Laminated Timber)
Application
Wood Building Systems
Topic
Acoustics and Vibration
Keywords
Impact Sound Transmission
Airborne Sound Transmission
Simulation
Research Status
Complete
Series
Case Studies in Construction Materials
Summary
Timber usage in the Australian construction industry has significantly increased due to its strength, aesthetic properties and extended allowances recently introduced in building codes. However, issues with acoustic performance of lightweight timber buildings were reported due to their inherit product variability and varying construction methods. This article reviews the recent literature on the transmissions of impact and airborne sounds, flanking transmission of timber buildings, and the state of computer prediction tools with reference to the Australian practice. An in-depth analysis of issues and an objective discussion related to acoustic performance of timber buildings are presented. Timber is a lightweight material and shows low airborne sound resistance in low frequency range. Attenuation of sound transmission with addition of mass, layer isolation, different products like cross-laminated timber and prefabrication are discussed. Challenges in measuring sound transmissions and reproducibility of results in low frequency ranges are discussed. Well-defined measurement protocols and refined computer simulation methods are required. The serviceability design criteria for modern lightweight timber applications in Australia need to be re-evaluated in the area of impact generated sound. Developing computer tools to predict airborne and impact sound transmission in lightweight timber buildings is quite challenging as several components such as timber members and complex connections with varying stiffnesses are non-homogeneous by nature. Further, there is a lack of experimentally validated and computationally efficient tools to predict the sound transmission in timber buildings. Computer prediction tools need to be developed with a focus on mid-frequency transmission over flanks and low-frequency transmission of timber and prefabricated buildings.
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Experimental and Numerical Dynamic Properties of Two Timber Footbridges Including Seasonal Effects

https://research.thinkwood.com/en/permalink/catalogue2937
Year of Publication
2021
Topic
Acoustics and Vibration
Application
Bridges and Spans
Author
Neilson, John
Ibisevic, Aida
Ugur, Hasanhüseyin
Battini, Jean-Marc
Crocetti, Roberto
Pacoste, Costin
Martinez-Rodrigo, Maria
Organization
KTH royal institute of technology
Jaume I University
Publisher
Springer
Year of Publication
2021
Format
Journal Article
Application
Bridges and Spans
Topic
Acoustics and Vibration
Keywords
Pedestrian Bridges
Dynamic Analysis
Damping
Finite Element Modelling
Dynamic Tests
Research Status
Complete
Series
Internation Journal of Civil Engineering
Summary
This paper deals with experimental and numerical dynamic analyses of two timber footbridges. Both bridges have a span of 35 m and consist of a timber deck supported by two timber arches. The main purpose is to investigate if the dynamic properties of the bridges are season dependent. To this end, experimental tests are performed during a cold day in winter and a warm day in spring in Sweden. The first bending and transverse mode frequencies increase 22% and 44%, respectively, due to temperature effects in the case of Vega Bridge. In the case of Hägernäs bridge, the corresponding values are 5% and 26%. For both bridges, the measured damping coefficients are similar in winter and spring. However, the damping coefficients for the first bending and transverse modes are different for both footbridges: about 1% for the Hägernäs bridge and 3% for the Vega bridge. Finite-element models are also implemented. Both numerical and experimental results show good correspondence. From the analyses performed, it is concluded that the connections between the different components of the bridges have a significant influence on the dynamic properties. In addition, the variation of the stiffness for the asphalt layer can explain the differences found in the natural frequencies between spring and winter. However, due to the uncertainties in the modelling of the asphalt layer, this conclusion must be taken with caution.
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Parameter identification for a point-supported cross laminated timber slab based on experimental and numerical modal analysis

https://research.thinkwood.com/en/permalink/catalogue2855
Year of Publication
2021
Topic
Serviceability
Acoustics and Vibration
Material
CLT (Cross-Laminated Timber)
Application
Floors
Author
Kawrza, Michael
Furtmüller, Thomas
Adam, Christoph
Maderebner, Roland
Organization
University of Innsbruck
Publisher
Springer
Year of Publication
2021
Format
Journal Article
Material
CLT (Cross-Laminated Timber)
Application
Floors
Topic
Serviceability
Acoustics and Vibration
Keywords
Modal Analysis
Complex Mode Shape
Point-Supported
Research Status
Complete
Series
European Journal of Wood and Wood Products
Summary
In this paper, the dynamic properties of a point-supported cross-laminated timber slab are studied in order to determine the elastic material parameters on this basis. A detailed experimental modal analysis of the slab with dimensions 16.0 m x 11.0 m is performed, and seven modes including the natural frequencies, damping ratios and mode shape components at 651 sensor positions are identified. The found mode shapes are complex due to environmental influences that occurred during the two-day measurement campaign. This error is corrected by eliminating these influences. A finite element model of the slab is presented, whose parameters in terms of material properties and boundary conditions are determined by a model updating procedure. Based on the modal properties of the seven experimentally identified modes, an accurate and robust parameter set is obtained, which can be used in further numerical studies of the considered CLT to check serviceability limit criteria.
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Deflection test and modal analysis of lightweight timber floors

https://research.thinkwood.com/en/permalink/catalogue3051
Year of Publication
2021
Topic
Acoustics and Vibration
Mechanical Properties
Author
Zhao, Xinyue
Huang, Yujie
Fu, Haiyan
Wang, Yunlu
Wang, Zheng
Sayed, Usama
Organization
Nanjing Forestry University
Publisher
Elsevier
Year of Publication
2021
Format
Journal Article
Topic
Acoustics and Vibration
Mechanical Properties
Keywords
Lightweight Timber Structure Building
Floor Structure
Static Load Test
Test Mode
Calculation Mode
Building Comfort
Research Status
Complete
Series
Journal of Bioresources and Bioproducts
Summary
In order to meet the objective requirements of the safety and comfort of the modern lightweight timber floors, and strengthen the research on the coupling performance of the lightweight timber floors vibration characteristics and the building comfort, this article discusses the floor of a two-story prefabricated lightweight timber building demonstration house. In this paper, the floor structure of a two-story light-weight wooden house has been carried out on structural calculation modal and experimental modal, static uniform load and concentrated load deflection value testing. The evaluation of the deflection value of the floor structure, the mode shape, the coupling of the fundamental frequency mode parameters, and the vibration comfort were also studied. The results show that the fundamental frequency simulation value, one-way modal test value and two-way modal test value of the floor structure all meet the requirements of BS-6472 (BS6472-1:2008). That is, the floor structure is not lower than 8 Hz design requirements, and meets the frequency of BS-6472(BS6472-1:2008). The weighted root mean square acceleration is lower than the requirement of 0.45 m/s2; the first three natural frequencies of the floor structure calculated by the finite element simulation are 16.413, 31.847 and 48.921 Hz, and the fundamental frequency mode is the bending vibration in the length and width directions. The second order is the bending mode in the length direction, and the third order is the bending mode in the width direction. The fundamental frequency of the two-way modal test of the floor structure is the first-order bending mode in the X direction; and the second-order natural frequency is the second-order bending vibration shape in the X direction. when the uniform load is mainly the weight of floor own, the simulated maximum deflection value is 1.0658 mm; the simulation is performed according to the standard value of 0.566 kN/m for the uniform load of the floor design, and the simulation is the largest. The maximum deflection value of the simulated floor is 1.47383 mm at its midpoint, which meets the requirements of National Building Code of Canada-2015 (NBCC). The maximum deflection limit of the light wood structure floor system is lower than 3 m and the maximum deflection limit is 2 mm; the six deflection value test lines simulated under a concentrated load of 1 kN all present a parabolic distribution and are symmetrical. The above results has engineering application value for promoting the research on the vibration characteristics of the fabricated lightweight timber floors structure and its optimization design.
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