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2177 records – page 1 of 218.

Modeling of Cross-Laminated Timber (CLT) panels loaded with combined out-of-plane bending and compression

https://research.thinkwood.com/en/permalink/catalogue2842
Year of Publication
2022
Topic
Mechanical Properties
Material
CLT (Cross-Laminated Timber)
Application
Columns
Walls
Author
Huang, Zirui
Huang, Dongsheng
Chui, Ying Hei
Shen, Yurong
Daneshvar, Hossein
Sheng, Baolu
Chen, Zhongfan
Organization
Southeast University
University of Alberta
Publisher
Elsevier
Year of Publication
2022
Format
Journal Article
Material
CLT (Cross-Laminated Timber)
Application
Columns
Walls
Topic
Mechanical Properties
Keywords
Rolling Shear
Beam-and-Column
Analytical Model
Load-Carrying Capacity
Research Status
Complete
Series
Engineering Structures
Summary
Rolling shear is one of the major concerns that significantly impact the performance of CLT walls if they are subjected to combined out-of-plane bending and compression loads. Because the effects of rolling shear and out-of-plane bending are coupled to each other, prediction of the load-carrying capacity of CLT wall is always a challenge for the design of CLT structures. Current design codes employ an Ayrton-Perry type interaction equation as the failure criterion to check the safety of a CLT panel loaded with combined bending and compression. Nevertheless, there is no model available to predict their load-carrying capacity. The presented work aims at developing an analytical model to predict the load-carrying capacity of CLT wall loaded with combined out-of-plane bending and compression. In total 12 five-layer CLT panels loaded with different initial load eccentricities were tested to investigate the failure modes. Observed during the test were two ultimate failure modes, i.e., compression crush on the concave side and tension rupture in convex side. Based on these failure modes and deeming the test member as a beam-column, an analytical model which takes rolling shear effects into account to predict the load-carry capacity of CLT compression-bending members was developed. An explicit formula based on compression failure mode was proposed. The model is capable of determining the distribution of rolling shear stress along longitudinal direction, rolling shear-induced axial force and moments in CLT beam-columns. By calculating the load-carrying capacities of the specimens tested in this study as well as the additional three- and seven-layer specimens tested by another studies, it was found that the compression failure mode-based formula can provide good agreements with the test results.
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Comparative Life Cycle Assessment of Mass Timber and Concrete Residential Buildings: A Case Study in China

https://research.thinkwood.com/en/permalink/catalogue2884
Year of Publication
2022
Topic
Environmental Impact
Material
CLT (Cross-Laminated Timber)
Author
Chen, Cindy
Pierobon, Francesca
Jones, Susan
Maples, Ian
Gong, Yingchun
Ganguly, Indroneil
Organization
Portland State University
University of Washington
Editor
Caggiano, Antonio
Publisher
MDPI
Year of Publication
2022
Format
Journal Article
Material
CLT (Cross-Laminated Timber)
Topic
Environmental Impact
Keywords
Mass Timber
Embodied Carbon
Climate Change
Built Environment
Life Cycle Analysis
Research Status
Complete
Series
Sustainability
Summary
As the population continues to grow in China’s urban settings, the building sector contributes to increasing levels of greenhouse gas (GHG) emissions. Concrete and steel are the two most common construction materials used in China and account for 60% of the carbon emissions among all building components. Mass timber is recognized as an alternative building material to concrete and steel, characterized by better environmental performance and unique structural features. Nonetheless, research associated with mass timber buildings is still lacking in China. Quantifying the emission mitigation potentials of using mass timber in new buildings can help accelerate associated policy development and provide valuable references for developing more sustainable constructions in China. This study used a life cycle assessment (LCA) approach to compare the environmental impacts of a baseline concrete building and a functionally equivalent timber building that uses cross-laminated timber as the primary material. A cradle-to-gate LCA model was developed based on onsite interviews and surveys collected in China, existing publications, and geography-specific life cycle inventory data. The results show that the timber building achieved a 25% reduction in global warming potential compared to its concrete counterpart. The environmental performance of timber buildings can be further improved through local sourcing, enhanced logistics, and manufacturing optimizations.
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Increasing Mass Timber Consumption in the U.S. and Sustainable Timber Supply

https://research.thinkwood.com/en/permalink/catalogue2888
Year of Publication
2022
Topic
Market and Adoption
Material
CLT (Cross-Laminated Timber)
Application
Wood Building Systems
Author
Comnick, Jeff
Rogers, Luke
Wheiler, Kent
Organization
University of Washington
Editor
Lauteri, Marco
Publisher
MDPI
Year of Publication
2022
Format
Journal Article
Material
CLT (Cross-Laminated Timber)
Application
Wood Building Systems
Topic
Market and Adoption
Keywords
Mass Timber
Embodied Carbon
Sustainable Timber Supply
Forest Inventory
Reforestation
Research Status
Complete
Series
Sustainability
Summary
Mass timber products are growing in popularity as a substitute for steel and concrete, reducing embodied carbon in the built environment. This trend has raised questions about the sustainability of the U.S. timber supply. Our research addresses concerns that rising demand for mass timber products may result in unsustainable levels of harvesting in coniferous forests in the United States. Using U.S. Department of Agriculture U.S. Forest Service Forest Inventory and Analysis (FIA) data, incremental U.S. softwood (coniferous) timber harvests were projected to supply a high-volume estimate of mass timber and dimensional lumber consumption in 2035. Growth in reserve forests and riparian zones was excluded, and low confidence intervals were used for timber growth estimates, compared with high confidence intervals for harvest and consumption estimates. Results were considered for the U.S. in total and by three geographic regions (North, South, and West). In total, forest inventory growth in America exceeds timber harvests including incremental mass timber volumes. Even the most optimistic projections of mass timber growth will not exceed the lowest expected annual increases in the nation’s harvestable coniferous timber inventory.
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Large-scale compartment fires to develop a self-extinction design framework for mass timber—Part 1: Literature review and methodology

https://research.thinkwood.com/en/permalink/catalogue2911
Year of Publication
2022
Topic
Fire
Material
CLT (Cross-Laminated Timber)
Application
Wood Building Systems
Author
Xu, Hangyu
Pope, Ian
Gupta, Vinny
Cadena, Jaime
Carrascal, Jeronimo
Lange, David
McLaggan, Martyn
Mendez, Julian
Osorio, Andrés
Solarte, Angela
Soriguer, Diana
Torero, Jose
Wiesner, Felix
Zaben, Abdulrahman
Hidalgo, Juan
Organization
The University of Queesland
University of College London
The University of Edinburgh
Publisher
Elsevier
Year of Publication
2022
Format
Journal Article
Material
CLT (Cross-Laminated Timber)
Application
Wood Building Systems
Topic
Fire
Keywords
Performance-based Design
Compartment Fires
Heat Transfer
Pretection of Wood
Large-scale
Mass Timber
Research Status
Complete
Series
Fire Safety Journal
Summary
Fire safety remains a major challenge for engineered timber buildings. Their combustible nature challenges the design principles of compartmentation and structural integrity beyond burnout, which are inherent to the fire resistance framework. Therefore, self-extinction is critical for the fire-safe design of timber buildings. This paper is the first of a three-part series that seeks to establish the fundamental principles underpinning a design framework for self-extinction of engineered timber. The paper comprises: a literature review introducing the body of work developed at material and compartment scales; and the design of a large-scale testing methodology which isolates the fundamental phenomena to enable the development and validation of the required design framework. Research at the material scale has consolidated engineering principles to quantify self-extinction using external heat flux as a surrogate of the critical mass loss rate, and mass transfer or Damköhler numbers. At the compartment scale, further interdependent, complex phenomena influencing self-extinction occurrence have been demonstrated. Time-dependent phenomena include encapsulation failure, fall-off of charred lamellae and the burning of the movable fuel load, while thermal feedback is time-independent. The design of the testing methodology is described in reference to these fundamental phenomena.
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Design of a novel seismic retrofitting system for RC structures based on asymmetric friction connections and CLT panels

https://research.thinkwood.com/en/permalink/catalogue2912
Year of Publication
2022
Topic
Seismic
Material
CLT (Cross-Laminated Timber)
Author
Aloisoio, Angelo
Boggian, Francesco
Tomasi, Roberto
Organization
Università degli Studi dell’Aquila
Università degli Studi di Trento
Norwegian University of Life Science
Publisher
Elsevier
Year of Publication
2022
Format
Journal Article
Material
CLT (Cross-Laminated Timber)
Topic
Seismic
Keywords
Friction-based Device
Seismic Protection
Structural Design
Reinforced-concrete Structures
Research Status
Complete
Series
Engineering Structures
Summary
Friction-based dampers are a valid solution for non-invasive seismic retrofitting interventions of existing structures, particularly reinforced-concrete (RC) structures. The design of friction-based dampers is challenging: underestimating the slip force prevents the full use of the potential of the device, which attains the maximum admissible displacement earlier than expected. By contrast, overestimating the slip force may cause delayed triggering of the device when the structure has suffered extensive damage. Therefore, designing the appropriate slip force is an optimization problem. The optimal slip force guarantees the highest inter-story drift reduction. The authors formulated the optimization problem for designing a specific class of friction-based dampers, the asymmetric friction connection (AFC), devised as part of the ongoing multidisciplinary Horizon 2020 research project e-SAFE (Energy and Seismic AFfordable rEnovation solutions). The seismic retrofitting technology involves the external application of modular prefabricated cross-laminated timber (CLT) panels on existing external walls. Friction dampers connect the CLT panels to the beams of two consecutive floors. The friction depends on the mutual sliding of two metal plates, pressed against each other by preloaded bolts. This study determines the optimal slip force, which guarantees the best seismic performance of an RC structural archetype. The authors investigate the nonlinear dynamic response of a coupled mechanical system (RC frame-friction damper) under a set of strong-motion earthquakes, using non-differential hysteresis models calibrated on the experimental cyclic responses. The solution of the optimization leads to the proposal of a preliminary simplified design procedure, useful for practitioners.
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Comparative life cycle assessment of cross laminated timber building and concrete building with special focus on biogenic carbon

https://research.thinkwood.com/en/permalink/catalogue2913
Year of Publication
2022
Topic
Environmental Impact
Energy Performance
Material
CLT (Cross-Laminated Timber)
Application
Wood Building Systems
Author
Andersen, Julie
Rasmussen, Nana
Ryberg, Morten
Organization
Technical University of Denmark
Publisher
Elsevier
Year of Publication
2022
Format
Journal Article
Material
CLT (Cross-Laminated Timber)
Application
Wood Building Systems
Topic
Environmental Impact
Energy Performance
Keywords
Life-Cycle Assessment
Biogenic Carbon
Forest Transformation
Research Status
Complete
Series
Energy and Buildings
Summary
This study conducted a consequential Life Cycle Assessment (LCA) on two similar mid-rise apartment buildings applying either concrete or cross laminated timber (CLT) as the main structural material. The study further investigated inclusion of biogenic carbon and how this affects environmental impacts related to Global warming. Thus, two assessment scenarios were applied: A Base scenario, without accounting for biogenic carbon and a Biogenic carbon scenario that include a GWPbio factor to account for the use of biogenic carbon. The CLT building had the lowest impact score in 11 of 18 impact categories including Global warming. Operational energy use was the main contributor to the total impact with some variation across impact scores, but closely followed by impacts embodied in materials (incl. End-of-Life). An evaluation of the potential forest transformations required for fulfilling future projections for new building construction in 2060 showed that about 3% of current global forest area would be needed. This share was essentially independent of the selected building material as the main driver for forest transformation was found to be energy use during building operation. Thus, focus should primarily be on reducing deforestation related to energy generation rather than deforestation from production of building materials.
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An experimental and modeling study on apparent bending moduli of cross-laminated bamboo and timber (CLBT) in orthogonal strength directions

https://research.thinkwood.com/en/permalink/catalogue2914
Year of Publication
2022
Topic
Mechanical Properties
Material
CLT (Cross-Laminated Timber)
Author
Li, Hao
Wang, Brad
Wang, Libin
Wei, Yang
Organization
Nanjing Forestry University
Southwest Forestry University
Publisher
Elsevier
Year of Publication
2022
Format
Journal Article
Material
CLT (Cross-Laminated Timber)
Topic
Mechanical Properties
Keywords
Bending Performance
Modeling Analysis
Cross-laminated Bamboo and Timber
Research Status
Complete
Series
Case Study in Construction Materials
Summary
In this paper, the bending properties of a 3-ply cross-laminated bamboo and timber (CLBT), prefabricated with the bamboo mat-curtain panel and hem-fir lumber, were examined in the major and minor strength directions, and a 3-ply hem-fir cross-laminated timber (CLT) was taken as a control group. The analytical model for the sum of the orthogonal apparent bending moduli with the two types of layer classifications were proposed, and the two kinds of contribution models were developed to analyze the apparent bending modulus variation behavior of the CLBT and CLT panels in the major and minor strength directions. The experimental results showed that since the CLBT group had more internal orthogonal structures, its difference in the bending properties between the major and minor strength directions was lower than that of the CLT group. Furthermore, the proposed contribution models quantitatively analyzed the relationship between the apparent bending moduli of the CLBT and CLT panels and the corresponding composition layer characteristics. The contribution model to characterize the apparent bending modulus in major and minor strength directions demonstrated good agreement with the test results. Based on this model interpreted by three-dimensional figures, the contribution variation characteristics in the major and minor strength directions were revealed.
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What Is the Impact of Mass Timber Utilization on Climate and Forests?

https://research.thinkwood.com/en/permalink/catalogue2921
Year of Publication
2022
Topic
Environmental Impact
Material
CLT (Cross-Laminated Timber)
Application
Wood Building Systems
Author
Pasternack, Rachel
Wishnie, Mark
Clarke, Caitlin
Wang, Yangyang
Belair, Ethan
Marshall, Steve
Gu, Hongmei
Nepal, Prakash
NDolezal, Franz
Lomax, Guy
Johnston, Craig
Felmer, Gabriel
Morales-Vera, Rodrigo
Puettmann, Maureen
Huevel, Robyn
Organization
USDA Forest Service Forest Products Laboratory
University of Exeter
Universidad de Chile
Universidad Católica del Maule
Editor
Ganguly, Indroneil
Publisher
MDPI
Year of Publication
2022
Format
Journal Article
Material
CLT (Cross-Laminated Timber)
Application
Wood Building Systems
Topic
Environmental Impact
Keywords
Life-Cycle Assessment
Climate Change
Embodied Carbon
Carbon Storage
Research Status
Complete
Series
Sustainability
Summary
As the need to address climate change grows more urgent, policymakers, businesses, and others are seeking innovative approaches to remove carbon dioxide emissions from the atmosphere and decarbonize hard-to-abate sectors. Forests can play a role in reducing atmospheric carbon. However, there is disagreement over whether forests are most effective in reducing carbon emissions when left alone versus managed for sustainable harvesting and wood product production. Cross-laminated timber is at the forefront of the mass timber movement, which is enabling designers, engineers, and other stakeholders to build taller wood buildings. Several recent studies have shown that substituting mass timber for steel and concrete in mid-rise buildings can reduce the emissions associated with manufacturing, transporting, and installing building materials by 13%-26.5%. However, the prospect of increased utilization of wood products as a climate solution also raises questions about the impact of increased demand for wood on forest carbon stocks, on forest condition, and on the provision of the many other critical social and environmental benefits that healthy forests can provide. A holistic assessment of the total climate impact of forest product demand across product substitution, carbon storage in materials, current and future forest carbon stock, and forest area and condition is challenging, but it is important to understand the impact of increased mass timber utilization on forests and climate, and therefore also on which safeguards might be necessary to ensure positive outcomes. To thus assess the potential impacts, both positive and negative, of greater mass timber utilization on forests ecosystems and emissions associated with the built environment, The Nature Conservancy (TNC) initiated a global mass timber impact assessment (GMTIA), a five-part, highly collaborative research program focused on understanding the potential benefits and risks of increased demand for mass timber products on forests and identifying appropriate safeguards to ensure positive outcomes.
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A Lifecycle Assessment of a Low-Energy Mass-Timber Building and Mainstream Concrete Alternative in Central Chile

https://research.thinkwood.com/en/permalink/catalogue2922
Year of Publication
2022
Topic
Environmental Impact
Material
CLT (Cross-Laminated Timber)
Application
Wood Building Systems
Author
Felmer, Gabriel
Morales-Vera, Rodrigo
Astroza, Rodrigo
González, Ignacio
Puettmann, Maureen
Wishnie, Mark
Organization
Universidad de Chile
Universidad Católica del Maule
Universidad Bernardo O’Higgins
Universidad de los Andes
Editor
Caggiano, Antonio
Publisher
MDPI
Year of Publication
2022
Format
Journal Article
Material
CLT (Cross-Laminated Timber)
Application
Wood Building Systems
Topic
Environmental Impact
Keywords
Life-Cycle Assessment
Mid-Rise
Carbon Storage
Passive Zero Carbon Housing
Research Status
Complete
Series
Sustainability
Summary
While high-rise mass-timber construction is booming worldwide as a more sustainable alternative to mainstream cement and steel, in South America, there are still many gaps to overcome regarding sourcing, design, and environmental performance. The aim of this study was to assess the carbon emission footprint of using mass-timber products to build a mid-rise low-energy residential building in central Chile (CCL). The design presented at a solar decathlon contest in Santiago was assessed through lifecycle analysis (LCA) and compared to an equivalent mainstream concrete building. Greenhouse gas emissions, expressed as global warming potential (GWP), from cradle-to-usage over a 50-year life span, were lower for the timber design, with 131 kg CO2 eq/m2 of floor area (compared to 353 kg CO2 eq/m2) and a biogenic carbon storage of 447 tons of CO2 eq/m2 based on sustainable forestry practices. From cradle-to-construction, the embodied emissions of the mass-timber building were 42% lower (101 kg CO2 eq/m2) than those of the equivalent concrete building (167 kg CO2 eq/m2). The embodied energy of the mass-timber building was 37% higher than that of its equivalent concrete building and its envelope design helped reduce space-conditioning emissions by as much as 83%, from 187 kg CO2 eq/m2 as estimated for the equivalent concrete building to 31 kg CO2 eq/m2 50-yr. Overall, provided that further efforts are made to address residual energy end-uses and end-of-life waste management options, the use of mass-timber products offers a promising potential in CCL for delivering zero carbon residential multistory buildings.
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Life Cycle Assessment of Cross-Laminated Timber Transportation from Three Origin Points

https://research.thinkwood.com/en/permalink/catalogue2923
Year of Publication
2022
Topic
Environmental Impact
Material
CLT (Cross-Laminated Timber)
Author
Hemmati, Mahboobeh
Messadi, Tahar
Gu, Hongmei
Organization
University of Arkansas
USDA Forest Service Forest Products Laboratory
Editor
D’Acierno, Luca
Publisher
MDPI
Year of Publication
2022
Format
Journal Article
Material
CLT (Cross-Laminated Timber)
Topic
Environmental Impact
Keywords
Life-Cycle Assessment
Mass Timber
Global Warming Potential
Transportation
Research Status
Complete
Series
Sustainability
Summary
Cross-laminated timber (CLT) used in the U.S. is mainly imported from abroad. In the existing literature, however, there are data on domestic transportation, but little understanding exists about the environmental impacts from the CLT import. Most studies use travel distances to the site based on domestic supply origins. The new Adohi Hall building at the University of Arkansas campus, Fayetteville, AR, presents the opportunity to address the multimodal transportation with overseas origin, and to use real data gathered from transporters and manufacturers. The comparison targets the environmental impacts of CLT from an overseas transportation route (Austria-Fayetteville, AR) to two other local transportation lines. The global warming potential (GWP) impact, from various transportation systems, constitutes the assessment metric. The findings demonstrate that transportation by water results in the least greenhouse gas (GHG) emission compared with freight transportation by rail and road. Transportation by rail is the second most efficient, and by road the least environmentally efficient. On the other hand, the comparison of the life cycle assessment (LCA) tools, SimaPro (Ecoinvent database) and Tally (GaBi database), used in this research, indicate a remarkable difference in GWP characterization impact factors per tonne.km (tkm), primarily due to the different database used by each software.
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2177 records – page 1 of 218.