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11 records – page 1 of 2.

Ambient Vibration Testing and Modal Analysis of Multi-Storey Cross Laminated Timber Buildings

https://research.thinkwood.com/en/permalink/catalogue237
Year of Publication
2014
Topic
Acoustics and Vibration
Wind
Serviceability
Material
CLT (Cross-Laminated Timber)
Application
Wood Building Systems
Author
Reynolds, Thomas
Bolmsvik, Åsa
Vessby, Johan
Chang, Wen-Shao
Harris, Richard
Bawcombe, Jonathan
Bregulla, Julie
Year of Publication
2014
Country of Publication
Canada
Format
Conference Paper
Material
CLT (Cross-Laminated Timber)
Application
Wood Building Systems
Topic
Acoustics and Vibration
Wind
Serviceability
Keywords
Modal Properties
Multi-Storey
Damping
Language
English
Conference
World Conference on Timber Engineering
Research Status
Complete
Notes
August 10-14, 2014, Quebec City, Canada
Summary
The ambient movement of three modern multi-storey timber buildings has been measured and used to determine modal properties. This information, obtained by a simple, unobtrusive series of tests, can give insights into the structural performance of these forms of building, as well as providing information for the design of future, taller timber buildings for dynamic loads. For two of the buildings, the natural frequency has been related to the lateral stiffness of the structure, and compared with that given by a simple calculation. In future tall timber buildings, a new design criterion is expected to become important: deflection and vibration serviceability under wind load. For multi-storey timber buildings there is currently no empirical basis to estimate damping for calculation of wind-induced vibration, and there is little information for stiffness under wind load. This study therefore presents a method to address those gaps in knowledge.
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Ambient Vibration Tests of a Cross-Laminated Timber Building

https://research.thinkwood.com/en/permalink/catalogue313
Year of Publication
2015
Topic
Wind
Material
CLT (Cross-Laminated Timber)
Application
Wood Building Systems
Shear Walls
Author
Reynolds, Thomas
Harris, Richard
Chang, Wen-Shao
Bregulla, Julie
Bawcombe, Jonathan
Publisher
ICE Publishing
Year of Publication
2015
Country of Publication
United Kingdom
Format
Journal Article
Material
CLT (Cross-Laminated Timber)
Application
Wood Building Systems
Shear Walls
Topic
Wind
Keywords
Damping
Dynamic Movement
In Situ
Multi-Storey
Stiffness
Modal Properties
Ambient Vibration Method
Language
English
Research Status
Complete
Series
Proceedings of the Institution of Civil Engineers - Construction Materials
ISSN
1747-6518
Summary
Cross-laminated timber has, in the last 6 years, been used for the first time to form shear walls and cores in multi-storey buildings of seven storeys or more. Such buildings can have low mass in comparison to conventional structural forms. This low mass means that, as cross-laminated timber is used for taller buildings still, their dynamic movement under wind load is likely to be a key design parameter. An understanding of dynamic lateral stiffness and damping, which has so far been insufficiently researched, will be vital to the effective design for wind-induced vibration. In this study, an ambient vibration method is used to identify the dynamic properties of a seven-storey cross-laminated timber building in situ. The random decrement method is used, along with the Ibrahim time domain method, to extract the modal properties of the structure from the acceleration measured under ambient conditions. The results show that this output-only modal analysis method can be used to extract modal information from such a building, and that information is compared with a simple structural model. Measurements on two occasions during construction show the effect of non-structural elements on the modal properties of the structure.
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Assessing Cross Laminated Timber (CLT) as an Alternative Material for Mid-Rise Residential Buildings in Cold Regions in China—A Life-Cycle Assessment Approach

https://research.thinkwood.com/en/permalink/catalogue1209
Year of Publication
2016
Topic
Energy Performance
Material
CLT (Cross-Laminated Timber)
Application
Wood Building Systems
Author
Liu, Ying
Guo, Haibo
Sun, Cheng
Chang, Wen-Shao
Publisher
MDPI
Year of Publication
2016
Country of Publication
Switzerland
Format
Journal Article
Material
CLT (Cross-Laminated Timber)
Application
Wood Building Systems
Topic
Energy Performance
Keywords
Life-Cycle Assessment
Cradle-to-Grave
China
Cold Regions
Severe Cold Regions
Energy Consumption
Mid-Rise
Residential
Language
English
Research Status
Complete
Series
Sustainability
Summary
Timber building has gained more and more attention worldwide due to it being a generic renewable material and having low environmental impact. It is widely accepted that the use of timber may be able to reduce the embodied energy of a building. However, the development of timber buildings in China is not as rapid as in some other countries. This may be because of the limitations of building regulations and technological development. Several new policies have been or are being implemented in China in order to encourage the use of timber in building construction and this could lead to a revolutionary change in the building industry in China. This paper is the first one to examine the feasibility of using Cross Laminated Timber (CLT) as an alternative solution to concrete by means of a cradle-to-grave life-cycle assessment in China. A seven-storey reference concrete building in Xi’an was selected as a case study in comparison with a redesigned CLT building. Two cities in China, in cold and severe cold regions (Xi’an and Harbin), were selected for this research. The assessment includes three different stages of the life span of a building: materialisation, operation, and end-of-life. The inventory data used in the materialisation stage was mostly local, in order to ensure that the assessment appropriately reflects the situation in China. Energy consumption in the operation stage was obtained from simulation by commercialised software IESTM, and different scenarios for recycling of timber material in the end-of-life are discussed in this paper. The results from this paper show that using CLT to replace conventional carbon intensive material would reduce energy consumption by more than 30% and reduce CO2 emission by more than 40% in both cities. This paper supports, and has shown the potential of, CLT being used in cold regions with proper detailing to minimise environmental impact.
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Does Timber-Concrete Floor System Save Energy?

https://research.thinkwood.com/en/permalink/catalogue2042
Year of Publication
2018
Topic
Energy Performance
Material
Timber-Concrete Composite
Application
Floors
Hybrid Building Systems
Author
Liu, Ying
Chang, Wen-Shao
Year of Publication
2018
Country of Publication
South Korea
Format
Conference Paper
Material
Timber-Concrete Composite
Application
Floors
Hybrid Building Systems
Topic
Energy Performance
Keywords
Thermal Mass
Simulation
Climate
Language
English
Conference
World Conference on Timber Engineering
Research Status
Complete
Online Access
Free
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Energy Saving and Carbon Reduction in the Operation Stage of Cross Laminated Timber Residential Buildings in China

https://research.thinkwood.com/en/permalink/catalogue1208
Year of Publication
2017
Topic
Energy Performance
Material
CLT (Cross-Laminated Timber)
Application
Wood Building Systems
Author
Guo, Haibo
Liu, Ying
Chang, Wen-Shao
Shao, Yu
Sun, Cheng
Publisher
MDPI
Year of Publication
2017
Country of Publication
Switzerland
Format
Journal Article
Material
CLT (Cross-Laminated Timber)
Application
Wood Building Systems
Topic
Energy Performance
Keywords
Energy Consumption
Carbon Emissions
Reinforced Concrete
China
Climate Zones
Simulation
Language
English
Research Status
Complete
Series
Sustainability
ISSN
2071-1050
Summary
This paper focused on energy consumption and carbon emission for heating and cooling during a building’s operation stage, and examined the energy effects of using Cross Laminated Timber (CLT) as an alternative building material to reinforced concrete (RC) in China’s 31 key cities located in different climate zones. The authors designed two seven-story residential buildings, which were constructed with RC framed and CLT systems, separately. This was followed by simulating the energy consumption using commercialized software IESTM under the different climate zones and calculating the carbon emissions. Comparisons were made between RC and CLT systems buildings on the basis of simulation data. The results show that the estimated energy consumption and carbon emission in CLT buildings are much lower than that of RC buildings in all studied cities, which indicates that CLT systems have good potential in reducing carbon emission and saving energy consumption compared to RC. The energy consumptions and carbon emissions in both concrete and CLT buildings are closely related to the climate zones. Buildings in Severe Cold and Cold Regions consumed the most energy and released more carbon. At the national level, the estimated energy consumption at the operation stage, in the studied building with RC frames and CLT system was approximately 465.1 MJ/m2 and 332.6 MJ/m2 per annum, respectively. Despite vast differences in China’s climate zones, the effects of energy saving and carbon reduction potentials of CLT buildings show little relationship to the climate zone. CLT buildings may result in a weighted 29.4% energy saving, which equals 24.6% carbon reductions, compared with RC buildings at the operation stage at national level, although it may vary in different climate zones.
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Experimental Tests on a Dowel-Type Timber Connection and Validation of Numerical Models

https://research.thinkwood.com/en/permalink/catalogue2897
Year of Publication
2017
Topic
Mechanical Properties
Material
Glulam (Glue-Laminated Timber)
Application
Frames
Author
Solarino, Fabio
Giresini, Linda
Chang, Wen-Shao
Huang, Haoyu
Organization
University of Pisa
The University of Sheffield
Beijing University of Technology
Publisher
MDPI
Year of Publication
2017
Country of Publication
Italy
United Kingdom
China
Format
Journal Article
Material
Glulam (Glue-Laminated Timber)
Application
Frames
Topic
Mechanical Properties
Keywords
Dowel Type Fastener
Rotational Stiffness
Damping
OpenSees
Language
English
Research Status
Complete
Series
Buildings
Summary
This paper examines the dynamic behaviour of timber framed buildings under wind and dynamic loads, focusing on the role of connections being experimentally tested. The main aim of this manuscript is to analyze the in-service dynamic behaviour of a semi-rigid moment-resisting dowel-type connection between timber beam and column. For this purpose, two laboratory tests have been performed, the first on a connection and another one on a portal frame. The results are used to validate a numerical model of the simple portal frame, analyzed in OpenSees. The obtained relationships are also discussed and compared with Eurocode rules. The main result is that the joint stiffness is calculated through the Eurocode (EC) formulation underestimates the experimental one. A mutual agreement is obtained between the numerical model, validated from the experimental stiffness value for the connections, and the experimental results on the portal frame.
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Lateral-Load Resistance of Cross-Laminated Timber Shear Walls

https://research.thinkwood.com/en/permalink/catalogue1238
Year of Publication
2017
Topic
Connections
Mechanical Properties
Material
CLT (Cross-Laminated Timber)
Application
Shear Walls
Author
Reynolds, Thomas
Foster, Robert
Bregulla, Julie
Chang, Wen-Shao
Harris, Richard
Ramage, Michael
Publisher
American Society of Civil Engineers
Year of Publication
2017
Country of Publication
United States
Format
Journal Article
Material
CLT (Cross-Laminated Timber)
Application
Shear Walls
Topic
Connections
Mechanical Properties
Keywords
Vertical Load
Lateral Load
Pullout Tests
Steel Connectors
Offset-Yield Criterion
Language
English
Research Status
Complete
Series
Journal of Structural Engineering
Summary
Cross-laminated timber shear wall systems are used as a lateral load resisting system in multistory timber buildings. Walls at each level typically bear directly on the floor panels below and are connected by nailed steel brackets. Design guidance for lateral load resistance of such systems is not well established and design approaches vary among practitioners. Two cross-laminated two-story timber shear wall systems are tested under vertical and lateral load, along with pull-out tests on individual steel connectors. Comprehensive kinematic behavior is obtained from a combination of discrete transducers and continuous field displacements along the base of the walls, obtained by digital image correlation, giving a measure of the length of wall in contact with the floor below. Existing design approaches are evaluated. A new offset-yield criterion based on acceptable permanent deformations is proposed. A lower bound plastic distribution of stresses, reflecting yielding of all connectors in tension and cross-grain crushing of the floor panel, is found to most accurately reflect the observed behavior.
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Nonlinear Pre-Yield Modal Properties of Timber Structures with Large-Diameter Steel Dowel Connections

https://research.thinkwood.com/en/permalink/catalogue132
Year of Publication
2014
Topic
Connections
Acoustics and Vibration
Material
Glulam (Glue-Laminated Timber)
Application
Beams
Frames
Author
Harris, Richard
Reynolds, Thomas
Chang, Wen-Shao
Publisher
ScienceDirect
Year of Publication
2014
Country of Publication
Netherlands
Format
Journal Article
Material
Glulam (Glue-Laminated Timber)
Application
Beams
Frames
Topic
Connections
Acoustics and Vibration
Keywords
Dowel-Type Connection
Modal Analysis
Cyclic Loading
Energy Dissipation
Language
English
Research Status
Complete
Series
Engineering Structures
Summary
In timber structures, the connections are generally flexible in comparison to the members they connect, and so contribute significantly to the dynamic properties of the structure. It is shown here that a widely-used form of connection, the dowel-type connection, exhibits nonlinear stiffness and energy dissipation, even at pre-yield loads, and that this nonlinearity affects the modal properties of structures with such connections. This study investigates that behaviour by modal analysis of a portal frame and a cantilever beam constructed from timber with steel dowel connections. The observed nonlinearity is explained qualitatively by considering the measured force-displacement response of individual connectors under cyclic load, which show a reduction in stiffness and an increase in energy dissipation with increasing amplitude of vibration. The structures were tested by modal analysis under slow sine sweep and pseudo-random excitation. Under pseudo-random excitation, a linear single degree-of-freedom curve fit was applied to estimate the equivalent linear modal properties for a given amplitude of applied force. Under slow sine sweep excitation, the frequency response function for the structures was observed to show features similar to a system with a cubic component of stiffness, and the modal properties of the structures were extracted using the equation of motion of such a system. The consequences for structural design and testing are that two key design parameters, natural frequency and damping, vary depending on the magnitude of vibration, and that parameters measured during in-situ testing of structures may be inaccurate for substantially different loads.
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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
Language
English
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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Repair and Reinforcement of Timber Columns and Shear Walls - A Review

https://research.thinkwood.com/en/permalink/catalogue867
Year of Publication
2015
Topic
Serviceability
Material
Solid-sawn Heavy Timber
Application
Shear Walls
Columns
Author
Chang, Wen-Shao
Publisher
ScienceDirect
Year of Publication
2015
Country of Publication
Netherlands
Format
Journal Article
Material
Solid-sawn Heavy Timber
Application
Shear Walls
Columns
Topic
Serviceability
Keywords
Reinforcement
Repair
Long-term
Language
English
Research Status
Complete
Series
Construction and Building Materials
Summary
Although it was found that most of the research foci were on reinforcement of timber connections and flexural members, columns and shear walls play a crucial role in the prevention of structural collapse. Recent trends to build taller timber structures, a demand for structures with larger span, and re-use of existing structures for different purposes have made reinforcement of timber columns and shear walls increasingly important. In addition, repair of damaged timber columns and shear walls so as to prevent further damage to the structures and elongate the life span of existing structures is also important. This paper provides an overview of techniques available to repair and strengthen timber columns and shear walls in both research and practice.
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11 records – page 1 of 2.