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1635 records – page 1 of 164.

Ultimate failure load analysis of cross-laminated timber panels subjected to in-plane compression

https://research.thinkwood.com/en/permalink/catalogue3310
Year of Publication
2023
Topic
Mechanical Properties
Material
CLT (Cross-Laminated Timber)
Author
Heinisuo, Markku
Pajunen, Sami
Aspila, Aku
Organization
Tampere University
Publisher
Elsevier
Year of Publication
2023
Format
Journal Article
Material
CLT (Cross-Laminated Timber)
Topic
Mechanical Properties
Keywords
Theory of Layered Beams
Axially Loaded Panel
Ultimate Failure Load Analysis
Research Status
Complete
Series
Structures
Summary
Cross-laminated timber (CLT) panels have proved their efficiency as vertical and horizontal load-carrying structures, and their design methods for serviceability and ultimate limit states are well defined. However, there is a lack of more general and versatile analytical methods for the ultimate load carrying capacity determination of CLT structures. In this paper, the classical layered beam theory is adopted for the ultimate failure load estimation of axially compressed CLT panels. The proposed method retains its accuracy both with an asymmetric layer setup and when the number of CLT layers exceeds five. The presented method is validated by adopting experimental test data from two test series produced by other researchers.
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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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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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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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Life Cycle Analysis of Innovative Technologies: Cold Formed Steel System and Cross Laminated Timber

https://research.thinkwood.com/en/permalink/catalogue3336
Year of Publication
2023
Topic
Environmental Impact
Energy Performance
Material
CLT (Cross-Laminated Timber)
Author
Luorio, Ornella
Gigante, Antonio
Masi, Rosa Francesca De
Organization
University of Leeds
University of Sannio
Publisher
MDPI
Year of Publication
2023
Format
Journal Article
Material
CLT (Cross-Laminated Timber)
Topic
Environmental Impact
Energy Performance
Keywords
Life Cycle Analysis
Cold Formed Steel
Net Zero
Embodied Carbon
Greenhouse Gases
Research Status
Complete
Series
Energies
Summary
Reducing the embodied and operational energy of buildings is a key priority for construction and real estate sectors. It is essential to prioritize materials and construction technologies with low carbon footprints for the design of new buildings. Off-site constructions systems are claimed to have the potential to deliver a low carbon build environment, but at present there are a lack of data about their real environmental impacts. This paper sheds lights on the environmental performance of two offsite technologies: cold formed steel and cross laminated timber. Specifically, the environmental impacts of a CFS technology are discussed according to six standard impact categories, which includes the global warming potential and the total use of primary energy. The study is based on a detailed cradle to gate life cycle analysis of a real case study, and discusses the impacts of both structural and non-structural components of CFS constructions. As a useful frame of reference, this work compares the environmental impacts of 1 m2 of walls and floors of CFS technology with those of cross laminated timber, which is spreading as innovative off-site technology for the development of nearly zero energy buildings, and a conventional reinforced masonry technology, which is largely adopted in the Italian construction sector. The paper concludes with the necessity to optimize structural systems to reduce the overall embodied carbon impacts.
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Innovative solutions to improved sound insulation of CLT floors

https://research.thinkwood.com/en/permalink/catalogue3339
Year of Publication
2023
Topic
Acoustics and Vibration
Material
CLT (Cross-Laminated Timber)
Application
Floors
Author
Ljunggren, Fredrik
Organization
Luleå University of Technology
Publisher
Elsevier
Year of Publication
2023
Format
Journal Article
Material
CLT (Cross-Laminated Timber)
Application
Floors
Topic
Acoustics and Vibration
Keywords
Sound Insulation
Low Frequencies
Impact Sound
Compressed Wood
Research Status
Complete
Series
Developments in the Built Environment
Summary
Building with cross laminated timber (CLT) has gain increased interest over the last years, but in common to other wood-based building systems, inadequate low-frequency sound insulation is seen as a problem. This paper deals with two methods to improve the sound insulation of CLT panels, normally made from spruce: 1) heavy CLT, introducing compressed, i.e. densified, spruce as well as alternative wood species, and 2) elastic layer based upon shear motion. In addition to a series of laboratory measurements, a full-scale CLT floor made of two 60 mm birch panels with a 12 mm elastic layer in between was tested in a two-room test mock-up. The results from the acoustical measurements showed that the floor has about 7 dB greater airborne and impact sound insulation for one-third octave bands, 50–3150 Hz, compared to a standard CLT floor of the same total height.
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Influence of inter-panel connections on vibration response of CLT floors due to pedestrian-induced loading

https://research.thinkwood.com/en/permalink/catalogue3340
Year of Publication
2023
Topic
Connections
Acoustics and Vibration
Material
CLT (Cross-Laminated Timber)
Application
Floors
Author
Milojevic, Marija
Racic, Vitomir
Marjanovic, Miroslav
Nefovska-Danilovic, Marija
Organization
University of Belgrade
Publisher
Elsevier
Year of Publication
2023
Format
Journal Article
Material
CLT (Cross-Laminated Timber)
Application
Floors
Topic
Connections
Acoustics and Vibration
Keywords
Walking Forces
Human-induced Vibrations
Single Surface Spline
Half-lapped Joint
Research Status
Complete
Series
Engineering Structures
Summary
Long-span cross-laminated timber (CLT) floors are typically an assembly of prefabricated CLT panels connected together on the site. The actual connections are commonly neglected in design calculations. Hence, a CLT floor is modelled either as a monolith slab or more frequently as a set of CLT panels with no connections at all. This paper presents a numerical study designed to examine the influence of two most common inter-panel connections, i.e. single surface spline and half-lapped joint, on vibration modes and vibration responses of a range of different CLT floors due to pedestrian-induced loading. Although the inter-panel connections are relatively complex in reality, they are modelled here as an equivalent 2D elastic strip between the CLT panels. This relatively simple yet robust model can be used with ease in design practice, regardless finite element (FE) software used to extract vibration modes of a CLT floor. The corresponding monolith floors and floors without inter-panel connections are studied for the comparison of the results. Vertical vibration responses are simulated for low-frequency and high-frequency floors using the corresponding walking force models given in a popular design guideline for footfall induced vibrations of civil engineering structures. Vibration responses were calculated for single pedestrian occupants and their walking paths parallel and perpendicular to the line of connection. The results showed that including the inter-panel connections in a FE model resulted in up to 2.5 higher RMS acceleration levels. Hence, the common practice of modelling CLT floors as monolith slabs or as a set of panels without connections should be left behind.
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Mechanical properties of fast-growing poplar glulam columns reinforced with steel plate

https://research.thinkwood.com/en/permalink/catalogue3341
Year of Publication
2023
Topic
Mechanical Properties
Material
Glulam (Glue-Laminated Timber)
Application
Columns
Author
Wang, Yuzhou
Liang, Chen
Zhang, Bingjie
Qu, Shuang
Gao, Ying
Zhang, Xiao
Organization
Shandong Xiehe University
Key Laboratory of Building Structural Retrofitting and Underground Space Engineering
Shandong Jianzhu University
Southeast University
Publisher
Elsevier
Year of Publication
2023
Format
Journal Article
Material
Glulam (Glue-Laminated Timber)
Application
Columns
Topic
Mechanical Properties
Keywords
Fast-growing Poplar
Steel Reinforced Glulam
Compression Test
Research Status
Complete
Series
Case Studies in Construction Materials
Summary
Fast-growing poplar with characteristics of fast growth, convenient processing, and strong adaptability is widely planted all over the world, but it is difficult to be directly used as structural timber due to its loose fibers and low strength. In order to enhance mechanical properties of fast-growing poplar, a new type of steel plate reinforced glulam fast-growing poplar is developed. Nine columns are tested including one fast-growing poplar column, two glued-laminated timber (glulam) columns and six steel plate reinforced glulam columns. The influencing factors include the steel plate thickness and eccentricity. Based on test results, axial stiffness, failure mode, load-displacement and load-strain relationships were investigated. Test results indicate that ultimate load and axial stiffness of steel plate reinforced glulam columns were respectively increased by 134.5–177.5% and 168.5–244.1% compared to fast-growing poplar column. With the increase of steel plate thickness and decrease of eccentricity, ultimate load increased by 10.9–18.3% and 27.2–92.3%, respectively. It was found that steel plate thickness and eccentricity have great impacts on bearing capacity of steel plate reinforced glulam columns. In addition, bearing capacity equation for steel plate reinforced glulam columns was established and test results coincide quite well with calculated results with difference of less than 5%.
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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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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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1635 records – page 1 of 164.