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608 records – page 1 of 61.

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
Country of Publication
China
Canada
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
Language
English
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
Country of Publication
United States
China
Format
Journal Article
Material
CLT (Cross-Laminated Timber)
Topic
Environmental Impact
Keywords
Mass Timber
Embodied Carbon
Climate Change
Built Environment
Life Cycle Analysis
Language
English
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
Country of Publication
United States
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
Language
English
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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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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Analysis of Cost Comparison and Effects of Change Orders During Construction: Study of a Mass Timber and a Concrete Building Project

https://research.thinkwood.com/en/permalink/catalogue2730
Year of Publication
2021
Topic
Cost
Material
CLT (Cross-Laminated Timber)
Author
Ahmed, Shafayet
Arocho, Ingrid
Publisher
ScienceDirect
Year of Publication
2021
Format
Journal Article
Material
CLT (Cross-Laminated Timber)
Topic
Cost
Keywords
Concrete Building
Cost Assessment
Change Orders
Construction
Cost Comparative Analysis
Language
English
Research Status
Complete
Series
Journal of Building Engineering
Summary
In recent years, timber has been considered as an alternative source of building material because of its sustainability and design efficiency. However, the cost competitiveness of timber buildings is still under study due to the lack of available cost information. This paper presents a comprehensive cost comparative analysis of a mass timber building mainly developed with cross-laminated timber (CLT). The actual construction cost of the project is compared with the modeled cost of the same building designed as a concrete option. The result shows that the construction cost of timber building is 6.43% higher than the modeled concrete building. The study further investigated the change orders associated with the project and found that the total cost of change orders contributed 5.62% to the final construction cost of mass timber building. The study is helpful to provide insight into the construction cost of typical mass timber buildings. It also can be used as a guide for the project owners to make decisions regarding their initial investments on a mass timber project.
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Variations of Moisture Content in Manufacturing CLT-Concrete Composite Slab Using Wet Construction Method

https://research.thinkwood.com/en/permalink/catalogue2732
Year of Publication
2021
Topic
Moisture
Material
CLT (Cross-Laminated Timber)
Application
Hybrid Building Systems
Author
Song, Yo-Jin
Baek, Seong-Yeob
Lee, In-Hwan
Hong, Soon-Il
Publisher
North Carolina State University
Year of Publication
2021
Country of Publication
United States
Format
Journal Article
Material
CLT (Cross-Laminated Timber)
Application
Hybrid Building Systems
Topic
Moisture
Keywords
Wet Construction Method
Moisture Content
Teak
Composite
Adhesive
Delamination
Language
English
Research Status
Complete
Series
BioResources
Summary
Construction of eco-friendly high-rise buildings using cross-laminated timber (CLT)-concrete composite (CCC) slabs is increasing. CLT and concrete, which are major component materials of the CCC slab, are significantly affected by moisture. In particular, the moisture content of concrete in the production process affects the quality of both materials. In this study, the effects of the wet construction method on CLT and concrete component materials are examined by monitoring the behavior of the CCC slab during curing time (28 d) and by evaluating the quality of the concrete and CLT after curing. When manufacturing the CCC using the wet construction method, moisture penetration from the concrete into the CLT during the curing time is suppressed by the shear bonding between the concrete and the CLT when an adhesive is used. This minimizes the effect of the moisture on both component materials, consequently yielding uniform compressive strength to the concrete after curing and preventing the deterioration of the CLT’s delamination performance. Therefore, the shear bonding method using an adhesive is expected to minimize the quality deterioration observed in concrete and CLT after curing.
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Structural Capacity of One-Way Spanning Large-Scale Cross-Laminated Timber Slabs in Standard and Natural Fires

https://research.thinkwood.com/en/permalink/catalogue2734
Year of Publication
2021
Topic
Fire
Mechanical Properties
Material
CLT (Cross-Laminated Timber)
Application
Floors
Ceilings
Author
Wiesner, Felix
Bartlett, Alastair
Mohaine, Siyimane
Robert, Fabienne
McNamee, Robert
Mindeguia, Jean-Christophe
Bisby, Luke
Organization
University of Queensland
The University of Edinburgh
CERIB Fire Testing Centre
Brandskyddslaget
University of Bordeaux
Publisher
Springer
Year of Publication
2021
Country of Publication
Australia
United Kingdom
France
Sweden
Format
Journal Article
Material
CLT (Cross-Laminated Timber)
Application
Floors
Ceilings
Topic
Fire
Mechanical Properties
Keywords
Deflection
Temperature
Load Bearing Capacity
Ventilation
Fire Safety
Language
English
Research Status
Complete
Series
Fire Technology
Summary
This paper describes selected observations, measurements, and analysis from a series of large-scale experiments on cross-laminated timber (CLT) slabs that were exposed to fire from below, using four different heating scenarios, with a sustained mechanical loading of 6.3 kN m per metre width of slab. The deflection response and in-depth timber temperatures are used to compare the experimental response against a relatively simple structural fire model to assess the load bearing capacity of CLT elements in fire, including during the decay phase of natural fires. It is demonstrated that the ventilation conditions in experiments with a fixed fuel load are important in achieving burnout of the contents before structural collapse occurs. A mechanics-based structural fire model is shown to provide reasonably accurate predictions of structural failure (or lack thereof) for the experiments presented herein. The results confirm the importance of the ventilation conditions on the fire dynamics, burning duration, and the achievement of functional fire safety objectives (i.e. maintaining stability and compartmentation), in compartments with exposed CLT.
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Experimental Investigation on the Long-Term Behaviour of Prefabricated Timber-Concrete Composite Beams with Steel Plate Connections

https://research.thinkwood.com/en/permalink/catalogue2741
Year of Publication
2021
Topic
Connections
Serviceability
Material
Timber-Concrete Composite
Application
Beams
Author
Shi, Benkai
Liu, Weiqing
Yang, Huifeng
Publisher
ScienceDirect
Year of Publication
2021
Format
Journal Article
Material
Timber-Concrete Composite
Application
Beams
Topic
Connections
Serviceability
Keywords
TCC
Prefabrication
Steel Plate
Long-term Behaviour
Interface Slip
Loading
Shear Connections
Deflection
Temperature
Humidity
Language
English
Research Status
Complete
Series
Construction and Building Materials
Summary
This paper presents the results of long-term experiments performed on three timber-concrete composite (TCC) beams. An innovative fabricated steel plate connection system, which consists of screws and steel plates embedded in concrete slabs, was adopted in the TCC beam specimens. The adopted shear connection can provide dry-type connection for TCC beams. Steel plates were embedded in concrete slabs while the concrete slab was constructed in factories. The timber beam and concrete slab can be assembled together using screws at the construction site. In this experimental programme, the beam specimens were subjected to constant loading for 613 days in indoor uncontrolled environments. The influence of long-term loading levels and the number of shear connections on the long-term performance of TCC beams was investigated and discussed. The mid-span deflection, timber strain, and interface relative slip at the positions of both connections and beam-ends were recorded throughout the long-term tests. It was found the long-term deflection of the TCC beam increased by approximately 60% while the long-term loads were doubled. Under the influence of the variable temperature and humidity, the TCC specimens with 8 shear connections showed slighter fluctuations compared with the TCC beam with 6 shear connections. In the 613-day observation period, the maximum deflection increment recorded was 6.56 mm for the specimen with eight shear connections and 20% loading level. A rheological model consisting of two Kelvin bodies was employed to fit the curves of creep coefficients. The final deflections predicted of all specimens at the end of 50-year service life were 2.1~2.7 times the initial deflections caused by the applied loads. All beam specimens showed relative small increments in mid-span deflection, strain and relative slip over time without any degradations, demonstrating the excellent long-term performance of TCC beams using the innovative steel plate connection system, which is also easily fabricated.
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Structural Performance of a Hybrid Timber Wall System for Emergency Housing Facilities

https://research.thinkwood.com/en/permalink/catalogue2745
Year of Publication
2021
Topic
Design and Systems
Seismic
Material
CLT (Cross-Laminated Timber)
Application
Walls
Hybrid Building Systems
Author
Casagrande, Daniele
Sinito, Ester
Izzi, Matteo
Pasetto, Gaia
Polastri, Andrea
Publisher
ScienceDirect
Year of Publication
2021
Format
Journal Article
Material
CLT (Cross-Laminated Timber)
Application
Walls
Hybrid Building Systems
Topic
Design and Systems
Seismic
Keywords
Prefabrication
Modular
Emergency Housing
Temporary Building
Hybrid Timber Frame
Seismic Behaviour
Language
English
Research Status
Complete
Series
Journal of Building Engineering
Summary
This paper presents an innovative and sustainable timber constructive system that could be used as an alternative to traditional emergency housing facilities. The system proposed in this study is composed of prefabricated modular elements that are characterized by limited weight and simple assembly procedures, which represent strategic advantages when it comes facing a strong environmental disaster (e.g. an earthquake). The complete dismantling of structural elements and foundations is granted thanks to specific details and an innovative connection system called X-Mini, capable of replacing traditional anchoring devices (i.e. hold downs and angle brackets) by resisting both shear and tension loads. This constructive system, denoted as Hybrid Timber Frame (HTF), takes advantage of the strong prefabrication, reduced weight of light-frame timber systems, and of the excellent strength properties of the Cross Laminated Timber (CLT) panels. Specifically, the solid-timber members typically used in the structural elements of light-frame systems are replaced by CLT linear elements. The results of experimental tests and numerical simulations are critically presented and discussed, giving a detailed insight into the performance of the HTF under seismic conditions.
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Nonlinear Static Seismic Response of a Building Equipped with Hybrid Cross-Laminated Timber Floor Diaphragms and Concentric X-Braced Steel Frames

https://research.thinkwood.com/en/permalink/catalogue2761
Year of Publication
2021
Topic
Seismic
Material
CLT (Cross-Laminated Timber)
Steel-Timber Composite
Application
Floors
Author
Roncari, Andrea
Gobbi, Filippo
Loss, Cristiano
Organization
University of British Columbia
University of Trento
Publisher
MDPI
Year of Publication
2021
Country of Publication
Canada
Italy
Format
Journal Article
Material
CLT (Cross-Laminated Timber)
Steel-Timber Composite
Application
Floors
Topic
Seismic
Keywords
Seismic Design
Hybrid Structures
Lateral Resistance
Semi-rigid Diaphragms
Load Distribution
Seismic Performance
Pushover Analysis
Nonlinear Static Analysis
Finite Element Model
Language
English
Research Status
Complete
Series
Buildings
Summary
Simplified seismic design procedures mostly recommend the adoption of rigid floor diaphragms when forming a building’s lateral force-resisting structural system. While rigid behavior is compatible with many reinforced concrete or composite steel-concrete floor systems, the intrinsic stiffness properties of wood and ductile timber connections of timber floor slabs typically make reaching a such comparable in-plane response difficult. Codes or standards in North America widely cover wood-frame construction, with provisions given for both rigid and flexible floor diaphragms designs. Instead, research is ongoing for emerging cross-laminated-timber (CLT) and hybrid CLT-based technologies, with seismic design codification still currently limited. This paper deals with a steel-CLT-based hybrid structure built by assembling braced steel frames with CLT-steel composite floors. Preliminary investigation on the performance of a 3-story building under seismic loads is presented, with particular attention to the influence of in-plane timber diaphragms flexibility on the force distribution and lateral deformation at each story. The building complies with the Italian Building Code damage limit state and ultimate limit state design requirements by considering a moderate seismic hazard scenario. Nonlinear static analyses are performed adopting a finite-element model calibrated based on experimental data. The CLT-steel composite floor in-plane deformability shows mitigated effects on the load distribution into the bracing systems compared to the ideal rigid behavior. On the other hand, the lateral deformation always rises at least 17% and 21% on average, independently of the story and load distribution along the building’s height.
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608 records – page 1 of 61.