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Analysis and enhancement of the new Eurocode 5 formulations for the lateral elastic deformation of LTF and CLT walls

https://research.thinkwood.com/en/permalink/catalogue3311
Year of Publication
2023
Topic
Mechanical Properties
Design and Systems
Material
CLT (Cross-Laminated Timber)
Author
Aloisio, Angelo
Boggian, Francesco
Sævareid, Håkon Østraat
Bjørkedal, Johan
Tomasi, Roberto
Organization
Norwegian University of Life Sciences
Università degli Studi di Trento
Università degli Studi dell’Aquila
Publisher
Elsevier
Year of Publication
2023
Format
Journal Article
Material
CLT (Cross-Laminated Timber)
Topic
Mechanical Properties
Design and Systems
Keywords
Light Timber Frames
Lateral Deformation
Shear Walls
Eurocode 5
Finite Element Modelling
Research Status
Complete
Series
Structures
Summary
This paper analyses the analytical formulations for the lateral elastic deformation of Light Timber Framed (LTF) and Cross-Laminated Timber (CLT) shear walls according to the new Eurocode 5 (EC5) proposal. Finite Element (FE) models and the Standard predictions are compared by emphasizing the role of each deformation contribution. A total of 1830 comparisons between analytical and numerical estimations are carried out by exploiting the Application Programming Interface of SAP2000 to modify the FE model parameters automatically. The parametric analyses proved that the numerical and analytical predictions are pretty consistent. Furthermore, in both LTF and CLT shear walls, the estimates for in-plane shear and rigid body sliding are in excellent agreement. Conversely, the analytical formulas for kinematic rocking are generally conservative for LTF and monolithic CLT shear walls, with an approximate 18%–19% discrepancy. The analytical expressions of the upcoming EC5 perfectly match the numerical model for segmented CLT shear walls under lateral forces and no vertical load. However, the presence of the vertical load determines a significant bias. Additionally, the predictions for bending deformations are not in good agreement. Therefore, the paper discusses possible enhancements for the equations proposed in the next generation of Eurocodes for the rocking deformation of segmented CLT walls to better conform with FE predictions.
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Analysis Behavior of Openings on Full-Size Cross-Laminated Timber (CLT) Frame Shear Walls Tested Monotonically

https://research.thinkwood.com/en/permalink/catalogue3335
Year of Publication
2023
Topic
Seismic
Material
CLT (Cross-Laminated Timber)
Application
Shear Walls
Author
Dungani, Rudi
Sulistyono
Karliati, Tati
Suhaya, Yoyo
Malik, Jamaludin
Alpian
Supriyati, Wahyu
Organization
Institut Teknologi Bandung
Kuningan University
Palangka Raya University
Publisher
MDPI
Year of Publication
2023
Format
Journal Article
Material
CLT (Cross-Laminated Timber)
Application
Shear Walls
Topic
Seismic
Keywords
Monotonic Test
Seismic Resistance
Wood-Frame
Opening
Research Status
Complete
Series
Forests
Summary
Walls, as components of the lateral-force-resisting system of a building, are defined as shear walls. This study aims to determine the behavior of shear wall panel cross-laminated-timber-based mangium wood (Acacia mangium Willd) (CLT-mangium) in earthquake-resistant prefabricated houses. The earthquake performance of CLT mangium frame shear walls panels has been studied using monotonic tests. The shear walls were constructed using CLT-mangium measuring 2400 mm × 1200 mm × 68 mm with various design patterns (straight sheathing, diagonal sheathing/45°, windowed shear wall with diagonal pattern and a door shear wall with a diagonal pattern). Shear wall testing was carried out using a racking test, and seismic force calculations were obtained using static equivalent earthquake analysis. CLT-mangium sheathing installed horizontally (straight sheathing) is relatively weak compared to the diagonal sheathing, but it is easier and more flexible to manufacture. The diagonal sheathing type is stronger and stiffer because it has triangulation properties, such as truss properties, but is more complicated to manufacture (less flexible). The type A design is suitable for low-intensity zones (2), and types B, D, E1 and E2 are suitable for moderate-intensity zones (3, 4), and type C is suitable for severe-intensity zones (5).
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An Investigation of the Impact of Water on Certain of the Mechanical and Physical Properties of Laminated Veneer Lumber (LVL) as Used in Construction

https://research.thinkwood.com/en/permalink/catalogue3358
Year of Publication
2023
Topic
Moisture
Material
LVL (Laminated Veneer Lumber)
Author
Juciene, Milda
Dobilaite, Vaida
Albrektas, Darius
Organization
Kaunas University of Technology
Publisher
MDPI
Year of Publication
2023
Format
Journal Article
Material
LVL (Laminated Veneer Lumber)
Topic
Moisture
Keywords
Strength
Water Rise Level
Water Absorption
Research Status
Complete
Series
Applied Sciences
Summary
Timber and timber products are renewable materials that, due to their durability and strength properties, meet the requirements of the construction industry, are widely used in buildings. An analysis of the scientific literature has shown that there is a lack of detailed research that fully investigates the influence of the rate of increase of the moisture content of the timber on the mechanical and, especially, the strength properties of the LVL panels. Upon immersion into water of the bottom of the specimen, the water starts rising quite quickly at the edge of the specimen, and the first six hours are the most critical. The levels of water rise inside the LVL specimen were less significant than at the edges. It was found that water significantly affects the bending strength of the panels, which, when the strength of the wet panel compared to the strength of the dry panel, decreases to 45% after one soak cycle and almost to 52% after two soak cycles. The tensile strength of the wet specimens is ~40% less than that of the dry specimens. The strength of the panels that were dried back to their initial state was found to be sufficient again, different from the initial strength only within the error limits; the strength properties of the building structure will not be affected.
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Behavior of cross-laminated timber panels during and after an ISO-fire: An experimental analysis

https://research.thinkwood.com/en/permalink/catalogue3343
Year of Publication
2023
Topic
Fire
Material
CLT (Cross-Laminated Timber)
Author
Vairo, Maurizio
Silva, Valdir Pignatta
Icimoto, Felipe Hideyoshi
Organization
University of Sao Paulo
Publisher
Elsevier
Year of Publication
2023
Format
Journal Article
Material
CLT (Cross-Laminated Timber)
Topic
Fire
Keywords
Charring
ISO-fire
Post-fire Stiffness Reduction
Cooling Phase
Finite Element Analysis
Research Status
Complete
Series
Results in Engineering
Summary
Cross-laminated timber has been used in buildings since the 1990s. In the last years, there has been a growing interest in the use of this technology, especially with the adoption of the product in increasingly taller buildings. Considering that the product is manufactured from a combustible material, wood, authorities that regulate the fire safety in buildings and the scientific community have carried out numerous research and fire tests, aiming to elaborate codes which contemplate the use of cross-laminated timber in tall buildings. This paper discusses the main results obtained from the fire resistance test of a cross-laminated timber slab carried out in the horizontal gas furnace (3.0 m × 4.0 m x 1.5 m) from the University of Sao Paulo. A vertical load of 3 kN/m2 was applied over the slab and the specimens were exposed to the standard fire curve for 30 min. In addition to the 30-min test, the research also evaluated the thermal behavior of the samples during the 24 h after the burners were turned off. Throughout the test, the slab maintained the integrity and the thermal insulation, and no falling-off of the charred layer was observed. However, the 24-h test indicated that it is mandatory to consider the loss of stiffness and strength of timber caused by the thermal wave observed during the decay phase.
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Behavior of Cross-Laminated Timber Panels Made from Fibre-Managed Eucalyptus nitens under Short-Term Serviceability Loads

https://research.thinkwood.com/en/permalink/catalogue3360
Year of Publication
2023
Topic
Mechanical Properties
Serviceability
Material
CLT (Cross-Laminated Timber)
Author
Liang, Yingwei
Taoum, Assaad
Kotlarewski, Nathan
Chan, Andrew
Holloway, Damien
Organization
University of Tasmania
Publisher
MDPI
Year of Publication
2023
Format
Journal Article
Material
CLT (Cross-Laminated Timber)
Topic
Mechanical Properties
Serviceability
Keywords
Hardwood CLT
Serviceability Performance
Eucalyptus nitens
Vibration
Deflection
Modulus of Elasticity
Research Status
Complete
Series
Buildings
Summary
In this study, the preliminary serviceability performance of cross-laminated timber (CLT) panels constructed from fibre-managed Eucalyptus nitens (E. nitens) was investigated via bending and vibration tests. Linear four-point bending tests were performed to determine the stiffness and deflection of all CLT panels under serviceability loads. The dynamic response of CLT panels was tested using a basketball and an accelerometer. The fundamental natural frequencies of all tested panels were above the minimum frequency limit (8 Hz) when extrapolated to spans of up to 4.4 m. The configurations of E. nitens CLT panels were based on different modulus of elasticity (MOE) values for each board. Using higher MOE timber boards as the top and bottom layers can significantly increase the serviceability performance of both bending and vibration tests. The same experiments were carried out on two CLT panels made of strength class C24 Spruce-Pine-Fir to compare the serviceability performance of E. nitens CLT. The results demonstrated that E. nitens is a reliable resource for CLT manufacturing, and exhibits better serviceability performance compared to Spruce CLT. This provides more sustainable options for a species traditionally destined for pulp.
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Bending Properties and Vibration Characteristics of Dowel-Laminated Timber Panels Made with Short Salvaged Timber Elements

https://research.thinkwood.com/en/permalink/catalogue3359
Year of Publication
2023
Topic
Mechanical Properties
Material
DLT (Dowel Laminated Timber)
Author
Giordano, Lorenzo
Derikvand, Mohammad
Fink, Gerhard
Organization
Aalto University
Publisher
MDPI
Year of Publication
2023
Format
Journal Article
Material
DLT (Dowel Laminated Timber)
Topic
Mechanical Properties
Keywords
Bending Stiffness
Eigenfrequency
Damping Ratio
Salvaged Plywood
Wooden Connectors
Reuse
Circular Economy
Research Status
Complete
Series
Buildings
Summary
Salvaged timber elements often have length limitations, and therefore, their reuse in structural products normally would require additional processing and end-to-end joining. This increases the costs of reusing such materials, which makes them even less attractive to the timber sector. In the presented research, a new approach is proposed for reusing short, salvaged timber elements combined with new (full-scale) timber boards to fabricate dowel-laminated timber (DLT) panels without significant processing or end-to-end joining or gluing. In this approach, salvaged timber elements are pressed in the system in such a way that they can contribute to the bending performance of the DLT panels by resisting compression stress. In order to evaluate the effectiveness, several small-scale and large-scale DLT panels were fabricated. Salvaged plywood tenons were used as connectors. The bending stiffness of the small-scale DLT panels and the first eigenfrequency, damping ratio, bending properties, and failure modes of the large-scale DLT panels were evaluated. The results exhibited that by using the proposed approach, the short, salvaged timber elements can contribute substantially to the bending stiffness of the DLT panels without requiring end-to-end joining or gluing. On average, about a 40% increase in the bending stiffness could be achieved by pressing in the salvaged timber elements, which results in relatively similar stiffness properties compared to conventional DLT panels. One further characteristic is that the failure of the panels, and therefore the panel’s strength, is mainly governed by the quality of the full-scale timber boards instead of the salvaged ones. This can be beneficial for practical use as the qualitative assessment of the strength properties of salvaged timber becomes less critical.
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Birch plywood as gusset plates in glulam frame via mechanical connectors: A combined experimental and numerical study

https://research.thinkwood.com/en/permalink/catalogue3348
Year of Publication
2023
Topic
Connections
Mechanical Properties
Material
Glulam (Glue-Laminated Timber)
Author
Wang, Yue
Wang, Tianxiang
Persson, Pontus
Hedlund, Patrik
Crocetti, Roberto
Wålinder, Magnus
Organization
KTH royal institute of technology
Publisher
Elsevier
Year of Publication
2023
Format
Journal Article
Material
Glulam (Glue-Laminated Timber)
Topic
Connections
Mechanical Properties
Keywords
Birch Plywood
Gusset Plate
Finite Element Method
Research Status
Complete
Series
Journal of Building Engineering
Summary
Birch is a short-lived hardwood species widespread in the Northern Hemisphere. Plywood made from birch has superior mechanical properties compared with that made from most softwoods, which makes it suitable for structural application. In this study, the feasibility of using birch plywood as gusset plates in timber-timber connections is presented. Test frames consisting of birch plywood gussets and glulam beams connected by nails were built and tested. A 2D analytical model based on truss theory and a 3D finite element model were proposed and constructed. Both models showed satisfactory agreements with the test results in terms of stiffness and strength. Tensile failure on the birch plywood gussets along the outermost row of nail holes was observed in the experiment. The observed failure modes and the stress distributions in the 3D numerical model suggest that the spreading angle (Whitmore effective width) theory should be considered in the design phase of birch plywood gusset plates. Besides, a modified spreading angle theory is proposed to both approximate the stress distribution and predict the load-bearing capacity.
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Capacity models for timber under compression perpendicular to grain with screw reinforcement

https://research.thinkwood.com/en/permalink/catalogue3372
Year of Publication
2023
Topic
Mechanical Properties
Author
Aloisio, Angelo
Ussher, Ebenezer
Fragiacomo, Massimo
Tomasi, Roberto
Organization
Università degli Studi dell’Aquila
Norwegian University of Life Sciences
Publisher
Springer
Year of Publication
2023
Format
Journal Article
Topic
Mechanical Properties
Keywords
Compression Perpendicular to the Grain
Failure Mode
Capacity Model
Eurocode Model
Research Status
Complete
Series
European Journal of Wood and Wood Products
Summary
This paper compares the performance of probabilistic and deterministic capacity models for reinforced timber members under compression perpendicular to the grain. A database collecting approximately 60 test results has been compiled by reviewing research papers and master’s and doctoral theses from the past twenty years. The capacity model proposed for the next generation of Eurocodes assesses the capacity as the minimum between the values associated with two failure modes, one at the contact plate and one at the screw tips. The main drawbacks of the model are the excessive elaborateness, given its limitation in accuracy and the fallacy in predicting the observed failure modes. In detail, the failure by the screw tips seldom occurs, although it was expected in more than half of the selected specimens. The authors attempted to simplify the capacity equation by proposing a generalized expression corresponding to the failure mode at the contact plate, corrected by a factor including the effects of load and screw arrangement and geometric details of the specimen. A deterministic mechanical model obtained by multiplying the timber strength by the contact area with a given coefficient performs better than the Eurocode model, which attempts to include the effect of load diffusion (R suitable fitting (R 2 ˜ 0.27 ). A constant factor equal to 2 yields a 2 ˜ 0.76 ). The best performance is achieved with a four-term polynomial, with adimensional addends, leading to an optimum fitting (R 2 ˜ 0.82).
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Comparative CO2 emissions of concrete and timber slabs with equivalent structural performance

https://research.thinkwood.com/en/permalink/catalogue3345
Year of Publication
2023
Topic
Environmental Impact
Material
CLT (Cross-Laminated Timber)
Timber-Concrete Composite
Author
Oh, Jae-Won
Park, Keum-Sung
Kim, Hyeon Soo
Kim, Ik
Pang, Sung-Jun
Ahn, Kyung-Sun
Oh, Jung-Kwon
Organization
Seoul National University
Korea Institute of Civil Engineering and Building Technology
Publisher
Elsevier
Year of Publication
2023
Format
Journal Article
Material
CLT (Cross-Laminated Timber)
Timber-Concrete Composite
Topic
Environmental Impact
Keywords
Carbon Dioxide
Reinforced Concrete
Structural Performance
Environmental Product Declaration
Research Status
Complete
Series
Energy and Buildings
Summary
Comparing the environmental impacts of building materials at the building level can be biased because a building design is optimized for a primary structural material. To achieve objective comparisons, this study compares the environmental impact of reinforced concrete (RC), cross-laminated timber (CLT), and timber-concrete composite (TCC) at the component level with equivalent structural performance. A slab was selected as the target structure member because its design does not consider lateral forces. Equivalent structural performance was defined as the minimum quantity of slab materials for comparable span and live load conditions. The functional unit for this study was defined as a 1 m2 slab. The system boundary covered the cradle-to-gate perspective, including raw material extraction, transportation, and manufacturing. The structural design method and material design values followed the Korean building code and standards. Environmental product declaration data developed in Korea were used to evaluate the carbon footprint. The CLT emitted 75 % less carbon dioxide, the primary greenhouse gases responsible for anthropogenic climate change, compared with RC regardless of conditions, while the TCC emitted 65 % less CO2, and its environmental impact improved as the span lengthened. The results also indicated that timber slabs are thinner than concrete slabs and can be structurally rational.
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Comparative study on connection properties of shear bolt and screw of thin cross-laminated timber panel

https://research.thinkwood.com/en/permalink/catalogue3379
Year of Publication
2023
Topic
Mechanical Properties
Material
CLT (Cross-Laminated Timber)
Author
Zhang, Daiyuan
Shen, Liming
Zhu, Xudong
Zhang, Sujun
Gong, Meng
Gao, Yuewen
Organization
Nanjing Forestry University
University of New Brunswick
Year of Publication
2023
Format
Journal Article
Material
CLT (Cross-Laminated Timber)
Topic
Mechanical Properties
Keywords
Connection Properties
Bolt
Screw
Research Status
Complete
Series
BioResources
Summary
Cross-laminated timber (CLT), a wood product with excellent shear resistance, is often used in modern timber constructions. Using the standards ASTM D1761-12 (2020) and NDS-2012 (2012), this study investigated the connection properties of shear bolts and screws in CLT panels. The specimens were made from spruce-pine-fir lumber and installed on a test platform using one high-strength bolt or eight screws, and then an upward load was applied to the top of the specimen. The results showed that the bolt connection provided a higher ultimate bearing capacity and elastic stiffness. The bolt exhibited virtually no deformation, and the CLT panel did not noticeably deteriorate when the connection was damaged. The distance between the bolt hole and the bottom of the CLT specimen and the angle between the outer-layer grain direction of the CLT panel and the load direction were both measured. Changes in the ductility coefficient value had an obvious effect on the connection performance of the shear bolts when the outer-layer grain direction of the CLT panel was consistent with the load direction. Contrastingly, when the outer-layer grain direction of the CLT panel was perpendicular to the load direction, the effect was negligible, and the yield load was nearly unchanged.
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Deep Learning Methods for Wood Composites Failure Predication

https://research.thinkwood.com/en/permalink/catalogue3361
Year of Publication
2023
Material
Glulam (Glue-Laminated Timber)
Author
Yang, Bin
Wu, Xinfeng
Hao, Jingxin
Liu, Tuoyu
Xie, Lisheng
Liu, Panpan
Li, Jinghao
Organization
Central South University of Forestry and Technology
Washington University in St. Louis
Editor
Krišták, Luboš
Publisher
MDPI
Year of Publication
2023
Format
Journal Article
Material
Glulam (Glue-Laminated Timber)
Keywords
Deep Learning
Wood Failure Percentage
UNet Model
Research Status
Complete
Series
Polymers
Summary
For glulam bonding performance assessment, the traditional method of manually measuring the wood failure percentage (WFP) is insufficient. In this paper, we developed a rapid assessment approach to predicate the WFP based on deep-learning (DL) techniques. bamboo/Larch laminated wood composites bonded with either phenolic resin (PF) or methylene diphenyl diisocyanate (MDI) were used for this sample analysis. Scanning of bamboo/larch laminated wood composites that have completed shear failure tests using an electronic scanner allows a digital image of the failure surface to be obtained, and this image is used in the training process of a deep convolutional neural networks (DCNNs).The result shows that the DL technique can predict the accurately localized failures of wood composites. The findings further indicate that the UNet model has the highest values of MIou, Accuracy, and F1 with 98.87%, 97.13%, and 94.88, respectively, compared to the values predicted by the PSPNet and DeepLab_v3+ models for wood composite failure predication. In addition, the test conditions of the materials, adhesives, and loadings affect the predication accuracy, and the optimal conditions were identified. The predicted value from training images assessed by DL techniques with the optimal conditions is 4.3%, which is the same as the experimental value measured through the traditional manual method. Overall, this advanced DL method could significantly facilitate the quality identification process of the wood composites, particularly in terms of measurement accuracy, speed, and stability, through the UNet model.
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Dimensional behavior of nail-laminated timber-concrete composite caused by changes in ambient air, and correlation among temperature, relative humidity, and strain

https://research.thinkwood.com/en/permalink/catalogue3374
Year of Publication
2023
Topic
Moisture
Material
NLT (Nail-Laminated Timber)
Timber-Concrete Composite
Author
Hwang, Sung-Wook
Chung, Hyunwoo
Lee, Taekyeong
Ahm, Kyung-Sun
Pang, Sung-Jun
Kim, Ji Yong
Bang, Junsik
Jung, Minjung
Oh, Jung-Kwon
Kwak, Hyo Won
Yeo, Hwanmyeong
Organization
Seoul National University
Year of Publication
2023
Format
Journal Article
Material
NLT (Nail-Laminated Timber)
Timber-Concrete Composite
Topic
Moisture
Keywords
Correlation
Dimensional Change
Moisture Content
Monitoring
Research Status
Complete
Series
BioResources
Summary
A timber-concrete composite (TCC) slab composed of nail-laminated timber (NLT) and topping concrete (TC) was developed for flooring applications. The NLT was laminated alternately with lumber and plywood. To investigate the dimensional behavior of the TCC slab, the temperature, relative humidity (RH), and dimensional changes of the slab exposed to outdoor air were monitored for 205 days. Temperature change was directly transmitted to both components, and RH change was gradually transmitted to the NLT. Concrete pouring caused a sharp increase in NLT width, which was the laminating direction of the nails. This resulted from swelling of the wood because of the moisture in the concrete mixture and loosening of the nail lamination. The member composition for the nail-laminating system, fastener type, and concrete volume help to secure the dimensional stability of the NLT. Cracks in the TC caused width deformation, which was recovered by drying shrinkage of the TC. Correlation analysis among temperature, RH, and strain indicated that dimensional changes in NLT correlated strongly with RH, while those in TC correlated strongly with temperature. The correlation between longitudinal strain in the TC and strain in the three directions of the NLT was attributed to the notches designed for mechanical connection.
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Does expanding wood use in construction and textile markets contribute to climate change mitigation?

https://research.thinkwood.com/en/permalink/catalogue3337
Year of Publication
2023
Topic
Environmental Impact
Author
Hurmekoski, Elias
Kunttu, Janni
Heinonen, Tero
Pukkala, Timo
Peltola, Heli
Organization
University of Helsinki
University of Eastern Finland
Publisher
Elsevier
Year of Publication
2023
Format
Journal Article
Topic
Environmental Impact
Keywords
Substitution
Climate Change Mitigation
Textile Markets
Construction Markets
Avoided Fossil Emissions
Wood Products
Life Cycle Assessment
Research Status
Complete
Series
Renewable and Sustainable Energy Reviews
Summary
Wood use is expanding to new markets, driven by the need to substitute fossil-intensive products and energy. Wood products can contribute to climate change mitigation, if they have a lower fossil footprint than alternative products serving the same function. However, the climate change mitigation potential is contingent on the net fossil and biogenic emissions over time, as well as the realism of the counterfactual scenario and market assumptions. This study aims to improve the consistency of assessing the avoided fossil emissions attributed to changes in wood use, and to estimate the additional mitigation potential of increased wood use in construction and textile markets based on wood harvested in Finland. The results show that, compared to baseline, an increase in the market share of wood leads to an increase in atmospheric CO2 concentration by 2050. Thus, the substitution impacts of wood use are not large enough to compensate for the reduction in forest carbon sinks in the short and medium term. This outcome is further aggravated, considering the decarbonization of the energy sector driven by the Paris Agreement, which lowers the fossil emissions of competing sectors more than those of the forest sector. The expected decarbonization is a highly desirable trend, but it will further lengthen the carbon parity period associated with an increase in wood harvest. This creates a strong motive to pursue shifts in wood uses instead of merely expanding all wood uses.
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Dynamic testing and numerical modelling of a pedestrian timber bridge at different construction stages

https://research.thinkwood.com/en/permalink/catalogue3344
Year of Publication
2023
Topic
Acoustics and Vibration
Material
Glulam (Glue-Laminated Timber)
Application
Bridges and Spans
Author
Bergenudd, Jens
Battini, Jean-Marc
Crocetti, Roberto
Pacoste, Costin
Organization
KTH royal institute of technology
Publisher
Elsevier
Year of Publication
2023
Format
Journal Article
Material
Glulam (Glue-Laminated Timber)
Application
Bridges and Spans
Topic
Acoustics and Vibration
Keywords
Pedestrian Bridge
Railings
Asphalt
Dynamic Analysis
Finite Element Modelling
Research Status
Complete
Series
Engineering Structures
Summary
This article studies the dynamic properties of a single span pedestrian timber bridge by in-situ testing and numerical modelling. The in-situ dynamic tests are performed at four different construction stages: (1) on only the timber structure, (2) on the timber structure with the railings, (3) on the timber structure with railings and an asphalt layer during warm conditions and (4) same as stage 3 but during cold conditions. Finite element models for the four construction stages are thereafter implemented and calibrated against the experimental results. The purpose of the study is to better understand how the different parts of the bridge contribute to the overall dynamic properties. The finite element analysis at stage 1 shows that longitudinal springs must be introduced at the supports of the bridge to get accurate results. The experimental results at stage 2 show that the railings contributes to 10% of both the stiffness and mass of the bridge. A shell model of the railings is implemented and calibrated in order to fit with the experimental results. The resonance frequencies decrease with 10–20% at stage 3 compared to stage 2. At stage 3 it is sufficient to introduce the asphalt as an additional mass in the finite element model. For that, a shell layer with surface elements is the best approach. The resonance frequencies increase with 15–30% between warm (stage 3) and cold conditions (stage 4). The stiffness of the asphalt therefore needs to be considered at stage 4. The continuity of the asphalt layer could also increase the overall stiffness of the bridge. The damping ratios increase at all construction stages. They are around 2% at warm conditions and around 2.5% at cold conditions for the finished bridge.
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Effects of building height on the sound transmission in cross-laminated timber Buildings – Airborne sound insulation

https://research.thinkwood.com/en/permalink/catalogue3342
Year of Publication
2023
Topic
Acoustics and Vibration
Material
CLT (Cross-Laminated Timber)
Application
Wood Building Systems
Author
Nilsson, Erik
Ménard, Sylvain
Bard, Delphine
Hagberg, Klas
Organization
University of Québec at Chicoutimi
Publisher
Elsevier
Year of Publication
2023
Format
Journal Article
Material
CLT (Cross-Laminated Timber)
Application
Wood Building Systems
Topic
Acoustics and Vibration
Keywords
Building Height
Viscoelastic Interlayer
Airborne Sound Insulation
Research Status
Complete
Series
Building and Environment
Summary
Buildings constructed with cross-laminated timber (CLT) are increasing in interest in several countries. Since CLT is a sustainable product, it can help the building industry to reduce greenhouse gas emissions. Furthermore, buildings constructed with CLT are increasing in building height, thereby increasing the load on the junctions and structural building elements further down in the building. Several studies have investigated how the load impacts the sound transmission between apartments. The majority found that an increasing load could have a negative effect on the vertical sound insulation. However, the findings are limited to a few measurements or building elements, and the studies only investigate junctions with resilient interlayers. This article aims to investigate if the building height, and thereby the load, affect the vertical airborne sound insulation between apartments on different stories in different cross-laminated timber buildings, with or without the presence of viscoelastic interlayers, and to quantify the effect. Four CLT buildings with different building systems, building heights, and the presence of viscoelastic interlayers in the junctions were measured. The airborne sound insulation between different apartment rooms was measured vertically for stories on the lower and higher levels. The difference in airborne sound insulation was calculated separately for each building, and the measurements indicate that the vertical airborne sound insulation reduces further down in the buildings. Therefore, results show that increasing load, by an increasing number of stories, has a negative effect on the vertical airborne sound insulation.
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Effects of fastener type, end distance, layer arrangement, and panel strength direction on lateral resistance of single shear lap joints in cross-laminated timber (CLT)

https://research.thinkwood.com/en/permalink/catalogue3312
Year of Publication
2023
Topic
Mechanical Properties
Material
CLT (Cross-Laminated Timber)
Author
Abdoli, Farshid
Rashidi, Maria
Rostampour-Haftkhani, Akbar
Layeghi, Mohammad
Organization
University of Tarbiat Modares
Western Sydney University
University of Mohaghegh Ardabili
University of Tehran
Publisher
Elsevier
Year of Publication
2023
Format
Journal Article
Material
CLT (Cross-Laminated Timber)
Topic
Mechanical Properties
Keywords
Lateral Resistance
End Distance
Layer Arrangement
Nails
Research Status
Complete
Series
Case Studies in Construction Materials
Summary
This research investigated the effects of the fastener type, end distance, layer arrangement, and panel strength direction on the lateral resistance of nailed and screwed single shear lap joints in CLT panels. Three-ply CLT panels were made out of poplar wood (Populus alba) with two layer arrangements: 0/90/0 ° and 0/45/0 °. The lateral resistance of nine types of fasteners with end distances of one, two, and three centimeters in two major and minor strength directions of CLT panels was measured by Instron (model 4486) testing machine. The major axis of CLT panels with the 0/45/0° arrangement showed the highest lateral resistance; however, its minor axis showed the lowest one. Among fasteners, Lag screws (10 mm) had the highest lateral resistance, while steel nails had the weakest. In all CLT samples, by changing the fastener type, end distance, layer arrangement, and panel strength direction, the lateral resistance changed 155.8 %, 72.1 %, 3.3 %, and 19.6 %, respectively. Furthermore, changing the failure mode of the fasteners from Im to IV, and CLT members from shear to bearing mode due to the increase in the end distance enhanced lateral resistance, leading to ductile behavior. The NDS, Eurocode 5, and CSA 086 theoretical models were applied to predict the yield lateral loads of the connections. The results showed that Eurocode 5, and CSA 086 better predicted the lateral load of connections with MAPE of 33.8 % and 34.24 %.
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Free
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Environmental Impact of a Mono-Material Timber Building Envelope with Enhanced Energy Performance

https://research.thinkwood.com/en/permalink/catalogue3395
Year of Publication
2023
Topic
Energy Performance
Author
Bucklin, Oliver
Bari, Roberta Di
Amtsberg, Felix
Menges, Achim
Organization
University of Stuttgart
Publisher
MDPI
Year of Publication
2023
Format
Journal Article
Topic
Energy Performance
Keywords
Computional Design
Digital Fabrication
Sustainable Construction
Building Physics
Research Status
Complete
Series
Sustainability
Summary
Broader adoption of timber construction is a strategy for reducing negative greenhouse gas (GHG) emissions created by the construction industry. This paper proposes a novel solid timber building envelope that uses computational design and digital fabrication to improve buildings’ energy performance. Timber beams are sawn with deep slits that improve thermal insulation and are milled with various joints for airtight, structural connections. To minimize embedded energy and to simplify disposal, the envelope is assembled without adhesives or metal fasteners. The building envelope is evaluated for thermal resistance and airtightness, and fabrication is evaluated for duration and power output during sawing. Finally, a Lifecycle Assessment (LCA) is carried out. The Global Warming Potential (GWP) is compared to that of other wood envelope systems with similar thermal conductance. Compared to other timber constructions with similar building physics properties, the proposed system showed lower GWP values (-15.63 kg CO2 eq./m² construction). The development and analysis demonstrate the potential to use digitally controlled subtractive manufacturing for improving the quality of solid timber to achieve higher environmental performance in building envelopes. However, further design and fabrication optimizations may be necessary to reduce required materials and production energy.
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Free
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Experimental analysis of timber-concrete composite behaviour with synthetic fibres

https://research.thinkwood.com/en/permalink/catalogue3396
Year of Publication
2023
Topic
Mechanical Properties
Material
Timber-Concrete Composite
Application
Floors
Author
Buka-Vaivade, K
Serdjuks, D
Zvirina, D
Pakrastins, L
Organization
Riga Technical University
Publisher
IOP Publishing
Year of Publication
2023
Format
Conference Paper
Material
Timber-Concrete Composite
Application
Floors
Topic
Mechanical Properties
Keywords
Synthetic Fibre
Bending Test
Conference
5th International Conference: Innovative Materials, Structures and Technologies (IMST 2022)
Research Status
Complete
Series
Journal of Physics: Conference Series
Summary
With the growing importance of the principles of sustainable construction, the use of load-bearing timber-concrete composite structures is becoming increasingly popular. Timber-concrete composite offers wider possibilities for the use of timber in construction, especially for large-span structures. The most significant benefit from combining these materials can be obtained by providing a rigid connection between the timber and concrete layers, which can be obtained by the adhesive timber-to-concrete connection produced by the proposed stone chips method. A sustainable solution involves the abandonment of steel longitudinal reinforcement. The use of such a solution in practice is often associated with fears of a fragile collapse. Therefore, the issue of how to increase the safety factor of the proposed material is topical now. The experimental investigation is made to determine the effect of synthetic fibre use on timber-concrete composite behaviour by testing a series of timber-concrete composite specimens with and without fibres in the concrete layer. The obtained results show that adding 0.5 % of synthetic macro fibres allows to abandon the use of longitudinal steel reinforcement and prevents the formation of large cracks in concrete and the disintegration of the concrete layer in case of collapse.
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Free
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Experimental and theoretical investigation on shear performances of glued-in perforated steel plate connections for prefabricated timber–concrete composite beams

https://research.thinkwood.com/en/permalink/catalogue3373
Year of Publication
2023
Topic
Mechanical Properties
Material
Timber-Concrete Composite
Application
Beams
Floors
Author
Yang, Huifeng
Lu, Yan
Ling, Xiu
Tao, Haotian
Shi, Benkai
Organization
Nanjing Tech University
Southeast University
Publisher
Elsevier
Year of Publication
2023
Format
Journal Article
Material
Timber-Concrete Composite
Application
Beams
Floors
Topic
Mechanical Properties
Keywords
Glued-in Perforated Steel Plate
Prefabricated Concrete Slab
Slip Modulus
Experimental Study
Research Status
Complete
Series
Case Studies in Construction Materials
Summary
Glued-in perforated steel plate (GIPSP) connections demonstrate significant shear strength and high slip modulus. Consequently, they indicate substantial potential for application in timber–concrete composite (TCC) structures according to the emerging tendencies in high-storey and large-span buildings. However, the application pattern in prefabricated TCC structures and the theoretical analysis of the shear performances of GIPSP connections are highly deficient. This hinders the application of this type of shear connection. In this study, the shear performances of GIPSP connections were evaluated using push-out tests. Ten groups of push-out specimens with different steel plate numbers, steel plate lengths, and concrete slab types were tested. The concrete slab types investigated in the experiments included a prefabricated concrete slab and cast-in-situ concrete slab. The experimental results were discussed in terms of the failure mode, load-carrying capacity, and slip modulus. The theoretical models for the load-carrying capacity related to the associate failure mode were discussed based on an analysis of the failure mechanisms. In addition, design proposals with regard to the load-carrying capacity and slip modulus of the GIPSP connection were presented. The research results can provide design guidance for TCC beams using GIPSP connections and prefabricated concrete slabs.
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Free
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Experimental investigation of hygrothermal behavior of wooden-frame house under real climate conditions

https://research.thinkwood.com/en/permalink/catalogue3338
Year of Publication
2023
Topic
Moisture
Author
Rahim, Mourad
Djedjig, Rabah
Wu, Dongxia
Bennacer, Rachid
Ganaoui, Mohammed EL
Organization
University of Lorraine
University of Paris-Saclay
Publisher
Elsevier
Year of Publication
2023
Format
Journal Article
Topic
Moisture
Keywords
Hygrothermal Behavior
Heat and Mass Transfer
Bio-based Building Envelope
Research Status
Complete
Series
Energy and Built Environment
Summary
This paper deals with the experimental investigation of hygrothermal behavior of wooden-frame building envelope. The experiment was based on in-situ monitoring of a full size experimental monozone house built at the University of Lorraine. Variations in temperature and relative humidity inside and outside the envelope were logged simultaneously with local meteorological data. Results showed the high coupling between temperature and relative humidity variations within the envelope materials. An overall hygrothermal response of the wall highlighted an interesting hygrothermal dynamic behavior of the envelope which may contribute to mitigate variations of relative humidity inside the building. Nevertheless, relative humidity evolves within a range of values that can lead to mold growth at a certain position which may alter wooden envelope life.
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Free
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