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Contribution of forest wood products to negative emissions: historical comparative analysis from 1960 to 2015 in Norway, Sweden and Finland

https://research.thinkwood.com/en/permalink/catalogue3083
Year of Publication
2018
Topic
Environmental Impact
Author
Iordan, Cristina-Maria
Hu, Xiangping
Arvesen, Anders
Kauppi, Pekka
Cherubini, Francesco
Organization
Norwegian University of Science and Technology (NTNU)
Publisher
Springer
Year of Publication
2018
Format
Journal Article
Topic
Environmental Impact
Keywords
Negative CO2 Emission
Forest Wood Products
Carbon Balance
Biomass
Forest Management
Bioenergy
Life-Cycle Assessment
Research Status
Complete
Series
Carbon Balance and Management
Summary
Background Forests and forest products can significantly contribute to climate change mitigation by stabilizing and even potentially decreasing the concentration of carbon dioxide (CO2) in the atmosphere. Harvested wood products (HWP) represent a common widespread and cost-efficient opportunity for negative emissions. After harvest, a significant fraction of the wood remains stored in HWPs for a period that can vary from some months to many decades, whereas atmospheric carbon (C) is immediately sequestered by vegetation re-growth. This temporal mismatch between oxidation of HWPs and C uptake by vegetation generates a net sink that lasts over time. The role of temporary carbon storage in forest products has been analysed and debated in the scientific literature, but detailed bottom-up studies mapping the fate of harvested materials and quantifying the associated emission profiles at national scales are rare. In this work, we quantify the net CO2 emissions and the temporary carbon storage in forest products in Norway, Sweden and Finland for the period 1960–2015, and investigate their correlation. We use a Chi square probability distribution to model the oxidation rate of C over time in HWPs, taking into consideration specific half-lives of each category of products. We model the forest regrowth and estimate the time-distributed C removal. We also integrate the specific HWP flows with an emission inventory database to quantify the associated life-cycle emissions of fossil CO2, CH4 and N2O. Results We find that assuming an instantaneous oxidation of HWPs would overestimate emissions of about 1.18 billion t CO2 (cumulative values for the three countries over the period 1960–2015).We also find that about 40 years after 1960, the starting year of our analysis, are sufficient to detect signs of negative emissions. The total amount of net CO2 emissions achieved in 2015 are about - 3.8 million t CO2, - 27.9 t CO2 and - 43.6 t CO2 in Norway, Sweden, and Finland, respectively. Conclusion We argue for a more explicit accounting of the actual emission rates from HWPs in carbon balance studies and climate impact analysis of forestry systems and products, and a more transparent inclusion of the potential of HWP as negative emissions in perspective studies and scenarios. Simply assuming that all harvested carbon is instantaneously oxidized can lead to large biases and ultimately overlook the benefits of negative emissions of HWPs.
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Damping in Timber Structures

https://research.thinkwood.com/en/permalink/catalogue106
Year of Publication
2012
Topic
Design and Systems
Material
Glulam (Glue-Laminated Timber)
Application
Wood Building Systems
Floors
Beams
Author
Labonnote, Nathalie
Organization
Norwegian University of Science and Technology
Year of Publication
2012
Format
Thesis
Material
Glulam (Glue-Laminated Timber)
Application
Wood Building Systems
Floors
Beams
Topic
Design and Systems
Keywords
Damping
Model
Panels
Spruce
Testing
Vibrations
Research Status
Complete
Summary
Key point to development of environmentally friendly timber structures, appropriate to urban ways of living, is the development of high-rise timber buildings. Comfort properties are nowadays one of the main limitations to tall timber buildings, and an enhanced knowledge on damping phenomena is therefore required, as well as improved prediction models for damping. The aim of this work has consequently been to estimate various damping quantities in timber structures. In particular, models have been derived for predicting material damping in timber members, beams or panels, or in more complex timber structures, such as floors. Material damping is defined as damping due to intrinsic material properties, and used to be referred to as internal friction. In addition, structural damping, defined as damping due to connections and friction in-between members, has been estimated for timber floors.
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Dynamic Response of Tall Timber Buildings Under Service Load - The DynaTTB Research Program

https://research.thinkwood.com/en/permalink/catalogue3015
Year of Publication
2020
Topic
Acoustics and Vibration
Application
Wood Building Systems
Author
Abrahamsen, Rune
Bjertnæs, Magne
Bouillot, Jacques
Brank, Bostjan
Cabaton, Lionel
Crocetti, Roberto
Flamand, Olivier
Garains, Fabien
Gavric, Igor
Germain, Olivier
Hahusseau, Ludwig
Hameury, Stephane
Johansson, Marie
Johansson, Thomas
Ao, Wai Kei
Kurent, Blaž
Landel, Pierre
Linderholt, Andreas
Malo, Kjell
Manthey, Manuel
Nåvik, Petter
Pavic, Alex
Perez, Fernando
Rönnquist, Anders
Stamatopoulos, Haris
Sustersic, Iztok
Tulebekova, Saule
Organization
Norwegian University of Science and Technology
University of Exeter
University of Ljubljana
Linnaeus University
Year of Publication
2020
Format
Conference Paper
Application
Wood Building Systems
Topic
Acoustics and Vibration
Keywords
Timber Building
Wind Load
Discomfort
Modelling
Damping
Full Scale
Conference
International Conference on Structural Dynamics
Research Status
Complete
Summary
Wind-induced dynamic excitation is becoming a governing design action determining size and shape of modern Tall Timber Buildings (TTBs). The wind actions generate dynamic loading, causing discomfort or annoyance for occupants due to the perceived horizontal sway – i.e. vibration serviceability failure. Although some TTBs have been instrumented and measured to estimate their key dynamic properties (natural frequencies and damping), no systematic evaluation of dynamic performance pertinent to wind loading has been performed for the new and evolving construction technology used in TTBs. The DynaTTB project, funded by the Forest Value research program, mixes on site measurements on existing buildings excited by heavy shakers, for identification of the structural system, with laboratory identification of building elements mechanical features coupled with numerical modelling of timber structures. The goal is to identify and quantify the causes of vibration energy dissipation in modern TTBs and provide key elements to FE modelers. The first building, from a list of 8, was modelled and tested at full scale in December 2019. Some results are presented in this paper. Four other buildings will be modelled and tested in spring 2021.
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Dynamic Testing and Numerical Modeling of Residential Building Modules

https://research.thinkwood.com/en/permalink/catalogue105
Year of Publication
2013
Topic
Design and Systems
Mechanical Properties
Material
Light Frame (Lumber+Panels)
Glulam (Glue-Laminated Timber)
Application
Wood Building Systems
Author
Jørstad, Anders
Organization
Norwegian University of Science and Technology
Publisher
Institutt for konstruksjonsteknikk
Year of Publication
2013
Format
Thesis
Material
Light Frame (Lumber+Panels)
Glulam (Glue-Laminated Timber)
Application
Wood Building Systems
Topic
Design and Systems
Mechanical Properties
Keywords
Finite Element Model
Tall Wood
Testing
Modal Analysis
Modules
Research Status
Complete
Summary
This thesis was initiated by a project planing the world's tallest timber building in Bergen, Norway, (the VHT project). The concept of the building is based on a load baring glulam frame with building modules stacked inside to create the residential area of the building. Calculation done by Sweco showed that more damping was needed to lower the accelerations in the top floor of the building. Since little was known about the dynamic properties of building modules and whether these could be used to increase the damping of the building, a survey was wanted. In this master thesis the dynamic properties of the building modules have been evaluated. This has been done by preforming dynamic test on building modules similar to those planed for the VHT project. Two test protocols were used to test the modules, an experimental modal analysis method using a modal hammer and a system identification method. The goal of the tests was to identify the modal frequencies, damping ratios and mode shapes of the building modules.The tested modules were modeled in a finite element (FE) method program and scaled to fit the size of the VHT modules. This way the dynamic properties of the VHT modules could be estimated. Simple shear frame models of the VHT modules were made to be implemented in a larger model of the VHT building to evaluate the effect of the modules on the entire structure. Several detailed FE models were made to evaluate how the separate parts of the modules influenced the dynamic response of the modules. An evaluation of the dynamic properties of the sound reducing material Stepisol was also done by dynamic testing in the lab and FE modeling. It was found that the tested modules had two translational modes and one torsional mode. The overall damping ratio of the modules was found to be roughly 3%. From the numerical tests the stiffness of the module walls were found to be more or less constant per meter wall. The walls can therefor easily be scaled for similar modules with different dimensions to predict the dynamic properties of the new modules.The Stepisol was found to influence the dynamic properties of the stacked building modules severely. The lab tests showed that Stepisol has a high material damping that helps increasing the damping in the modules. The FE models showed that layers of Stepisol makes the stacked modules a lot less stiff and it is a key feature that can be used to alter the dynamic behavior of stacked modules.
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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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Modeling stiffness of connections and non-structural elements for dynamic response of taller glulam timber frame buildings

https://research.thinkwood.com/en/permalink/catalogue3000
Year of Publication
2022
Topic
Mechanical Properties
Material
Glulam (Glue-Laminated Timber)
Author
Tulebekova, Saule
Malo, Kjell
Rønnquist, Anders
Nåvik, Petter
Organization
Norwegian University of Science and Technology
Publisher
Elsevier
Year of Publication
2022
Format
Journal Article
Material
Glulam (Glue-Laminated Timber)
Topic
Mechanical Properties
Keywords
Tall Timber Buildings
Glulam Connections
Finite Element Modeling
Dynamic Identification
Model Updating
Research Status
Complete
Series
Engineering Structures
Summary
Currently, there is limited knowledge of the dynamic response of taller glue laminated (glulam) timber buildings due to ambient vibrations. Based on previous studies, glulam frame connections, as well as non-structural elements (external timber walls and internal plasterboard partitions) can have a significant impact on the global stiffness properties, and there is a lack of knowledge in modeling and investigation of their impact on the serviceability level building dynamics. In this paper, a numerical modeling approach with the use of “connection-zones” suitable for analyzing the taller glulam timber frame buildings serviceability level response is presented. The “connection-zones” are generalized beam and shell elements, whose geometry and properties depend on the structural elements that are being connected. By introducing “connection-zones”, the stiffness in the connections can be estimated as modified stiffness with respect to the connected structural elements. This approach allows for the assessment of the impact of both glulam connection stiffness and non-structural element stiffness on the dynamic building response due to service loading. The results of ambient vibration measurements of an 18-storey glulam timber frame building, currently the tallest timber building in the world, are reported and used for validation of the developed numerical model with “connection-zones”. Based on model updating, the stiffness values for glulam connections are presented and the impact of non-structural elements is assessed. The updating procedure showed that the axial stiffness of diagonal connections is the governing parameter, while the rotational stiffness of the beam connections does not have a considerable impact on the dynamic response of the glulam frame type of building. Based on modal updating, connections exhibit a semi-rigid behavior. The impact of non-structural elements on the mode shapes of the building is observed. The obtained values can serve as a practical reference for engineers in their prediction models of taller glulam timber frame buildings serviceability level response.
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Moisture Induced Stresses in Glulam: Effect of Cross Section Geometry and Screw Reinforcement

https://research.thinkwood.com/en/permalink/catalogue176
Year of Publication
2012
Topic
Mechanical Properties
Moisture
Material
Glulam (Glue-Laminated Timber)
Application
Beams
Author
Angst-Nicollier, Vanessa
Organization
Norwegian University of Science and Technology
Year of Publication
2012
Format
Thesis
Material
Glulam (Glue-Laminated Timber)
Application
Beams
Topic
Mechanical Properties
Moisture
Keywords
Moisture Induced Stress
Mechanosorption
Numerical model
Tensile Strength
Tensile Stress
Load Bearing Capacity
Self-Tapping Screws
Climate
Research Status
Complete
Summary
This thesis presents a state of the art on moisture induced stresses in glulam, complemented with own findings. These are covered in detail in the appended papers. The first objective was to find a suitable model to describe moisture induced stresses, in particular with respect to mechanosorption. A review of existing models led to the conclusion that the selection of correct material parameters is more critical to obtain reliable results than the formulation of the mechanosorption model. A series of laboratory tests was thus performed in order to determine the parameters required for the model and to experimentally measure moisture induced stresses in glulam subjected to one dimensional wetting/drying. Special attention was paid to using glulam from the same batch for all the experimental measurements in order to calibrate the numerical model reliably. The results of the experiments confirmed that moisture induced stresses are larger during wetting than during drying, and that the tensile stresses could clearly exceed the characteristic tensile strength perpendicular to grain.
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Moment-resisting beam-to-column timber connections with inclined threaded rods: Structural concept and analysis by use of the component method

https://research.thinkwood.com/en/permalink/catalogue3132
Year of Publication
2022
Topic
Connections
Author
Stamatopoulos, Haris
Malo, Kjell Arne
Vilguts, Aivars
Organization
Norwegian University of Science and Technology
Publisher
Elsevier
Year of Publication
2022
Format
Journal Article
Topic
Connections
Keywords
Moment-resisting Connection
Threaded Rod
Rotational Stiffness
Research Status
Complete
Series
Construction and Building Materials
Summary
The use of moment-resisting frames with semi-rigid connections as a lateral load-carrying system in timber buildings can reduce the need for bracing with diagonal members or walls and allow for more open and flexible architecture. The overall performance of moment-resisting frames depends largely on the properties of their connections. Screwed-in threaded rods with wood screw thread feature high axial stiffness and capacity and they may be used as fasteners in beam-to-column, moment-resisting timber connections. In the present paper, a structural concept for a beam–to-column, moment-resisting timber connection based on threaded rods is presented and explained. Analytical expressions for the estimation of the rotational stiffness and the forces in the rods were derived based on a component-method approach. The analytical predictions for stiffness were compared to experimental results from full scale tests and the agreement was good.
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Numerical Models for Dynamic Properties of a 14 Storey Timber Building

https://research.thinkwood.com/en/permalink/catalogue274
Year of Publication
2012
Topic
Design and Systems
Connections
Material
Glulam (Glue-Laminated Timber)
Application
Wood Building Systems
Author
Utne, Ingunn
Organization
Norwegian University of Science and Technology
Year of Publication
2012
Format
Thesis
Material
Glulam (Glue-Laminated Timber)
Application
Wood Building Systems
Topic
Design and Systems
Connections
Keywords
Dynamic Properties
Finite Element Model
Research Status
Complete
Summary
The world tallest timber building with height of 45 meters, is planned for Bergen, Norway. In this master thesis the dynamic properties of the case building, as proposed by Sweco and Artec, are investigated. The proposed structural concept with a glulam frame and power-storeys, have never previously been built, and it is desirable to develop and understanding of the dynamic problems concerning this building. Previous work have shown problems with acceleration levels for tall timber building, mostly due to the material properties of timber. Timber has high flexibility and strength combined with low weight. The main aim of the work have been to build a 3D-model of the case building in a finite element program, where numerical methods can be used to find the dynamic properties of the building. The wind load and acceleration levels are investigated, and found to be reasonable compared to various criterions presented. The effect of the stiffness in the connections, as well as the use of apartment modules are investigated. In addition a dynamic analysis is run, and stochastic subspace state space system identification is used to verify the model. This can later be used for verification of the actual building when finished, and will be an important method to determine the actual damping and stiffness. Based on the findings in this work, the concept is assumed feasible, possible with some changes an even better concept is achieved. It will be exciting to see how Sweco will develop the concept further in the next planning phase.
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Optimization framework for cost and carbon emission of timber floor elements

https://research.thinkwood.com/en/permalink/catalogue3001
Year of Publication
2022
Topic
Cost
Environmental Impact
Application
Floors
Author
Nesheim, Sveinung
Mela, Kristo
Malo, Kjell
Labonnote, Nathalie
Organization
Norwegian University of Science and Technology
Tampere University
Publisher
Elsevier
Year of Publication
2022
Format
Journal Article
Application
Floors
Topic
Cost
Environmental Impact
Keywords
Cost Optimization
Carbon Emission Reduction
Timber Floor
Eurocode 5
Research Status
Complete
Series
Engineering Structures
Summary
Long-span timber floor elements increase the adaptability of a building and they exhibit a significant market potential. High cost of the floor elements is a challenge, and the timber sector is under substantial pressure to find more economical solutions without weakening otherwise favourable environmental performance. The range of technical timber-based materials and components, structural typologies, overlays and ceiling systems represent an immense solution space when searching for a competitive design for a specific building application. Finding the optimum solution requires a computational procedure. In this study a recent development for the accounting of manufacturing resources for timber elements is utilized to build an optimization framework for cost and ECO2 minimisation of timber floor elements finalized at the factory gate. The design of the element is formulated as a discrete optimization problem which is solved by a mixed-integer sequential linearization procedure. Various material combinations and constraint combinations are treated. The optimization framework provides a tool for rapid design exploration that can be used in timber floor design situations. The results of the calculations carried out in this study provide insight on the general trends of optimum floor elements. The optimization model is used to analyse the characteristics of the optimum designs, and a comparison between the current and the proposed method for the second generation of Eurocode 5 is chosen as a vehicle for demonstrating achievable implications.
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17 records – page 1 of 2.