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15 records – page 1 of 2.

Analysis of Rotational Stiffness of the Timber Frame Connection

https://research.thinkwood.com/en/permalink/catalogue2763
Year of Publication
2020
Topic
Connections
Material
Glulam (Glue-Laminated Timber)
Application
Frames
Author
Johanides, Marek
Kubíncová, Lenka
Mikolášek, David
Lokaj, Antonín
Sucharda, Oldrich
Mynarcík, Petr
Publisher
MDPI
Year of Publication
2020
Format
Journal Article
Material
Glulam (Glue-Laminated Timber)
Application
Frames
Topic
Connections
Keywords
Rotational Stiffness
Frame Connection
Screw
Numerical Model
FEM
Finite Element Model
Mechanical Fasteners
Language
English
Research Status
Complete
Series
Sustainability
Summary
Initially, timber was considered only as an easily accessible and processable material in nature; however, its excellent properties have since become better understood. During the discovery of new building materials and thanks to new technological development processes, industrial processing technologies and gradually drastically decreasing forest areas, wood has become an increasingly neglected material. Load-bearing structures are made mostly of reinforced concrete or steel elements. However, ecological changes, the obvious problems associated with environmental pollution and climate change, are drawing increasing attention to the importance of environmental awareness. These factors are attracting increased attention to wood as a building material. The increased demand for timber as a building material offers the possibility of improving its mechanical and physical properties, and so new wood-based composite materials or new joints of timber structures are being developed to ensure a better load capacity and stiffness of the structure. Therefore, this article deals with the improvement of the frame connection of the timber frame column and a diaphragm beam using mechanical fasteners. In common practice, bolts or a combination of bolts and pins are used for this type of connection. The subject of the research and its motivation was to replace these commonly used fasteners with more modern ones to shorten and simplify the assembly time and to improve the load capacity and rigidity of this type of frame connection.
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Bending Capacity of Orthogonal and Parallel Glulam T-section Beams

https://research.thinkwood.com/en/permalink/catalogue2476
Year of Publication
2020
Topic
Mechanical Properties
Material
Glulam (Glue-Laminated Timber)
Application
Beams
Bridges and Spans
Author
Wang, Jiejun
Yang, Tao
Ning, Fan
Rao, Zhenyu
Publisher
Eastern Macedonia and Thrace Institute of Technology (EMaTTech)
Year of Publication
2020
Country of Publication
Greece
Format
Journal Article
Material
Glulam (Glue-Laminated Timber)
Application
Beams
Bridges and Spans
Topic
Mechanical Properties
Keywords
Bearing Capacity
Stiffness
Integrity
Strain
Deflection
Ultimate Bearing Capacity
Shear Strength
Finite Element Model
Displacement
Failure Mechanism
Ductility
Language
English
Research Status
Complete
Series
Journal of Engineering Science and Technology Review
ISSN
1791-2377
Online Access
Free
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Development of Mass Timber Wall System Based on Nail Laminated Timber

https://research.thinkwood.com/en/permalink/catalogue2526
Year of Publication
2020
Topic
Design and Systems
Material
NLT (Nail-Laminated Timber)
Application
Walls
Author
Zhang, Chao
Lee, George
Lam, Frank
Organization
Timber Engineering and Applied Mechanics (TEAM) Laboratory
Year of Publication
2020
Country of Publication
Canada
Format
Report
Material
NLT (Nail-Laminated Timber)
Application
Walls
Topic
Design and Systems
Keywords
Shear
Stiffness
Fasteners
Fastener Type
Load
Language
English
Research Status
Complete
Summary
This project studied the feasibility and performance of a mass timber wall system based on Nail Laminated Timber (NLT) for floor/wall applications, in order to quantify the effects of various design parameters. Thirteen 2.4 m × 2.4 m shear walls were manufactured and tested in this phase. Together with another five specimens tested before, a total eighteen shear wall specimens and ten configurations were investigated. The design variables included fastener type, sheathing thickness, number of sheathings, sheathing material, nailing pattern, wall opening, and lumber orientation. The NLT walls were made of SprucePine-Fir (SPF) No. 2 2×4 (38 mm × 89 mm) lumber and Oriented Strand Lumber (OSB) or plywood sheathing. They were tested under monotonic and reverse-cyclic loading protocols, in accordance with ASTM E564-06 (2018) and ASTM E2126-19, respectively. Compared to traditional wood stud walls, the best performing NLT based shear wall had 2.5 times the peak load and 2 times the stiffness at 0.5-1.5% drift, while retaining high ductility. The advantage of these NLT-based wall was even greater under reverse-cyclic loading due to the internal energy dissipation of NLT. The wall with ring nails had higher stiffness than the one with smooth nails. But the performance of ring nails deteriorated drastically under reverse-cyclic loading, leading to a considerably lower capacity. Changing the sheathing thickness from 11 mm to 15 mm improved the strength by 6% while having the same initial stiffness. Adding one more face of sheathing increased the peak load and stiffness by at least 50%. The wall was also very ductile as the load dropped less than 10% when the lateral displacement exceeded 150 mm. The difference created by sheathing material was not significant if they were of the same thickness. Reducing the nailing spacing by half led to a 40% increasing in the peak load and stiffness. Having an opening of 25% of the area at the center, the lateral capacity and stiffness reached 75% or more of the full wall. A simplified method to estimate the lateral resistance of this mass timber wall system was proposed. The estimate was close to the tested capacity and was on the conservative side. Recommendations for design and manufacturing the system were also presented.
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Development of Novel Standardized Structural Timber Elements Using Wood-Wood Connections

https://research.thinkwood.com/en/permalink/catalogue2747
Year of Publication
2020
Topic
Design and Systems
Connections
Material
CLT (Cross-Laminated Timber)
Author
Gamerro, Julien
Publisher
Lausanne, EPFL
Year of Publication
2020
Format
Thesis
Material
CLT (Cross-Laminated Timber)
Topic
Design and Systems
Connections
Keywords
Timber Construction
Connections
Digital Fabrication
Design for Manufacturing and Assembly
Structural Design
Structural Frameworks
Semi-Rigid Connection
Experimental
Shear Strength
Compression Strength
Wood-Wood Connections
Bending Test
Bending Stiffness
Numerical Model
Load Carrying Capacity
Slip Modulus
Language
English
Research Status
Complete
Summary
Traditional wood-wood connections, widely used in the past, have been progressively replaced by steel fasteners and bonding processes in modern timber constructions. However, the emergence of digital fabrication and innovative engineered timber products have offered new design possibilities for wood-wood connections. The design-to-production workflow has evolved considerably over the last few decades, such that a large number of connections with various geometries can now be easily produced. These connections have become a cost-competitive alternative for the edgewise connection of thin timber panels. Several challenges remain in order to broaden the use of this specific joining technique into common timber construction practice: (1) prove the applicability at the building scale, (2) propose a standardized construction system, (3) develop a convenient calculation model for practice, and (4) investigate the mechanical behavior of wood-wood connections. The first building implementation of digitally produced through-tenon connections for a folded-plate structure is presented in this work. Specific computational tools for the design and manufacture of more than 300 different plates were efficiently applied in a multi-stakeholder project environment. Cross-laminated timber panels were investigated for the first time, and the potential of such connections was demonstrated for different engineered timber products. Moreover, this work demonstrated the feasibility of this construction system at the building scale. For a more resilient and locally distributed construction process, a standardized system using through-tenon connections and commonly available small panels was developed to reconstitute basic housing components. Based on a case-study with industry partners, the fabrication and assembly processes were validated with prototypes made of oriented strand board. Their structural performance was investigated by means of a numerical model and a comparison with glued and nailed assemblies. The results showed that through-tenon connections are a viable alternative to commonly used mechanical fasteners. So far, the structural analysis of such construction systems has been mainly achieved with complex finite element models, not in line with the simplicity of basic housing elements. A convenient calculation model for practice, which can capture the semi-rigid behavior of the connections and predict the effective bending stiffness, was thus introduced and subjected to large-scale bending tests. The proposed model was in good agreement with the experimental results, highlighting the importance of the connection behavior. The in-plane behavior of through-tenon connections for several timber panel materials was characterized through an experimental campaign to determine the load-carrying capacity and slip modulus required for calculation models. Based on the test results, existing guidelines were evaluated to safely apply these connections in structural elements while a finite element model was developed to approximate their performance. This work constitutes a firm basis for the optimization of design guidelines and the creation of an extensive database on digitally produced wood-wood connections. Finally, this thesis provides a convenient design framework for the newly developed standardized timber construction system and a solid foundation for research into digitally produced wood-wood connections.
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Edge Connection Technology for Cross Laminated Timber (CLT) Floor Slabs Promoting Two-Way Action

https://research.thinkwood.com/en/permalink/catalogue2718
Year of Publication
2020
Topic
Connections
Material
CLT (Cross-Laminated Timber)
Application
Floors
Author
Asselstine, Julian
Publisher
University of British Columbia
Year of Publication
2020
Country of Publication
Canada
Format
Thesis
Material
CLT (Cross-Laminated Timber)
Application
Floors
Topic
Connections
Keywords
Bending
Two-Way
Self-Tapping Screws
Stiffness
Modulus of Elasticity
Language
English
Research Status
Complete
Summary
Cross-laminated timber (CLT) is a class of engineered wood product with the ability to act as a flat plate floor system transferring loads in two-directions due to the orthogonally crossed layers. Currently, dimensional limitations from manufacturing and transportation limit the minor span to about 3.0 m. This results in under utilization of the bending properties of the cross-layers or the choice of a different product because of the common use of one-way bending support conditions such as drop beams simply supporting the ends of the longer span. This study investigates the performance of a newly developed edge connection system to maintain continuity in the minor direction span of CLT and promote two-way bending action. Three connections utilizing a tension splice fastened to the underside of the panel edges with self-tapping screws are investigated, with experimental results showing promise to maintain a high level of stiffness. This connection system was placed in the maximum moment location of the minor span - attaining a connected span modulus of elasticity up to 1.17 times the intact span modulus of elasticity, indicating a reinforcing effect created by the connection. Further, the minor direction span is additionally stiffened through the use of parallel-strand lumber rim beams fixed to the edges of the CLT in the minor direction span and hidden within the cross-section of the CLT. ANSYS finite element modelling calibrated and validated from the experimental results show the potential of this flat-plate system using 5-layer CLT to reach column spacing of 6.0 m by 6.0 m limited by deflection under a serviceability limit state uniformly distributed load of 3.25 kPa. This claim maintains a high degree of conservatism, as the boundary stress obtained from the minimum observed failure load is greater than 6 times the maximum stress at an ultimate limit state load of 4.67 kPa. This system has the ability to expand the flexibility for designers to utilize CLT more efficiently and create large open floor spaces uninhibited by drop-beams.
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Effect of Design Parameters on Mass Timber Floor Vibration Performance

https://research.thinkwood.com/en/permalink/catalogue2683
Year of Publication
2020
Topic
Acoustics and Vibration
Design and Systems
Material
DLT (Dowel Laminated Timber)
Application
Floors
Author
Hu, Lin
Organization
FPInnovations
Year of Publication
2020
Country of Publication
Canada
Format
Report
Material
DLT (Dowel Laminated Timber)
Application
Floors
Topic
Acoustics and Vibration
Design and Systems
Keywords
Concrete Topping
Plywood
Vibration Performance
Bending Stiffness
Language
English
Research Status
Complete
Summary
Mass timber is a generic name for a broad range of thick and heavy wood products such as cross-laminated timber (CLT), dowel-laminated timber (DLT), nail-laminated timber (NLT), and gluelaminated timber (GLT), among others. So far, vibration-controlled design methods have been developed mostly for CLT floors.
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Effet des Paramètres de Conception Sur la Performance Vibratoire des Planchers Massifs en Bois

https://research.thinkwood.com/en/permalink/catalogue2684
Year of Publication
2020
Topic
Acoustics and Vibration
Energy Performance
Material
DLT (Dowel Laminated Timber)
Application
Floors
Author
Hu, Lin
Organization
FPInnovations
Year of Publication
2020
Country of Publication
Canada
Format
Report
Material
DLT (Dowel Laminated Timber)
Application
Floors
Topic
Acoustics and Vibration
Energy Performance
Keywords
Concrete Topping
Plywood
Vibration Performance
Bending Stiffness
Language
French
Research Status
Complete
Summary
La construction massive en bois est un terme générique qui englobe une grande variété de produits du bois épais et lourds, notamment le bois lamellé-croisé (CLT), le bois lamellé-goujonné (DLT), le bois lamellé-cloué et le bois lamellé-collé (GLT). À ce jour, les méthodes de conception à vibrations contrôlées ont surtout été élaborées pour les planchers en CLT.
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Experimental Research on Structural Behaviors of Glulam I-Beam with a Special-Shaped Section

https://research.thinkwood.com/en/permalink/catalogue2447
Year of Publication
2020
Topic
Design and Systems
Mechanical Properties
Material
Glulam (Glue-Laminated Timber)
Application
Beams
Author
Yang, Ruyuan
Hong, Chaokun
Zhang, Xiaofeng
Yuan, Quan
Sun, Youfu
Publisher
Tech Science Press
Year of Publication
2020
Country of Publication
United States
Format
Journal Article
Material
Glulam (Glue-Laminated Timber)
Application
Beams
Topic
Design and Systems
Mechanical Properties
Keywords
Flange Thickness
Shear Pan Ratio
Stiffener
Stiffness
Bending
Failure
Language
English
Research Status
Complete
Series
Journal of Renewable Materials
Online Access
Free
Resource Link
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Flexural Strengthening of Composite Bridge Glued Laminated Timber Beams-Concrete Plate Using CFRP Layers

https://research.thinkwood.com/en/permalink/catalogue2587
Year of Publication
2020
Topic
Design and Systems
Material
Glulam (Glue-Laminated Timber)
Application
Bridges and Spans
Author
Mujiman, M
Igustiany, F
Hakiki, R
Publisher
IOP Publishing Ltd
Year of Publication
2020
Format
Journal Article
Material
Glulam (Glue-Laminated Timber)
Application
Bridges and Spans
Topic
Design and Systems
Keywords
CFRP
Carbon Fiber Reinforced Polymer
Flexural Strength
Stiffness
Ductility
Reinforcement
Language
English
Research Status
Complete
Series
IOP Conference Series: Materials Science and Engineering
Summary
The timber bridge design although economical, often has difficulty producing enough rigidity so that a solution is needed to solve it. The use of CFRP (Carbon Fiber Reinforced Polymer) as a reinforcement of structural elements if properly designed and implemented can produce an effective and efficient composite structure. The experimental study aims to analyse the strength, stiffness and ductility of flexural strengthening composite bridge glued laminated timber beams-concrete plates using CFRP layers. The dimensions of the composite glued laminated timber beams 100/180 mm and concrete plate 75/300 mm with a length of 2,480 mm. The number of specimens is 3 composite glued laminated timber beams-concrete plate consisting of 1 test beam without CFRP reinforcement, 1 test beam with one layer CFRP reinforcement, and 1 test beam with three layer CFRP reinforcement. Experimental testing of flexural loads is done with two load points where each load is placed at 1/3 span length. The test results show that the strength of composite laminated timber beams glued - concrete plates BN; BL-1; BL-2 in a row 81.32; 82.82; 82.69 kN/mm; stiffness in a row 7.51; 8.22; 6.32 kN/mm and successive ductility of 16.67; 28.83; 20.21.
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Influence of Openings on the Shear Strength and Stiffness of Cross Laminated Timber (CLT) Panels

https://research.thinkwood.com/en/permalink/catalogue2710
Year of Publication
2020
Topic
Mechanical Properties
Material
CLT (Cross-Laminated Timber)
Application
Walls
Shear Walls
Author
Aljuhmani, Ahmad
Ogasawawra, A.
Atsuzawa, E.
Alwashali, Hamood
Shegay, A. V.
Tafheem, Zasiah
Maeda, Masaki
Year of Publication
2020
Format
Conference Paper
Material
CLT (Cross-Laminated Timber)
Application
Walls
Shear Walls
Topic
Mechanical Properties
Keywords
Diagonal Compression Test
Openings
Lateral Strength
In-Plane Shear Stiffness
Panels
Language
English
Conference
World Conference on Earthquake Engineering
Research Status
Complete
Summary
In the last decade, cross laminated timber (CLT) has been receiving increasing attention as a promising construction material for multi-storey structures in areas of high seismicity. In Japan, application of CLT in building construction is still relatively new; however, there is increasing interest in CLT from researchers as well as construction companies. Furthermore, the Japanese government is providing construction cost subsidies for new CLT structures as it is a carbon neutral and sustainable material. The high shear and compressive strength of CLT makes it a good candidate for use as shear walls in mid-rise buildings. One important aspect of CLT walls, and one that is presently poorly understood, is the influence of openings on the shear carrying capacity. Openings are often necessary in CLT panels either in form of windows, doors, lift shaft openings or installation of building services. Concerning this aspect, the code regulations in Japan are relatively strict, such that if openings exceeded certain prescribed limits, the entire CLT panel is considered as a non-structural element, and its contribution to lateral strength is totally ignored. Furthermore, as the maximum opening size is usually governed by edge distance constraints, the size of openings that designers can use is inevitably limited by the standard sizes supplied by the manufacturers. As a result, designers are obligated to adopt very small opening size. This is thought to be a very conservative approach. The main purpose of this paper is to experimentally evaluate the influence of openings on seismic capacity; strength and stiffness reduction, as well as failure mode with changing opening size and opening aspect ratio. In addition, check the validity of the Japanese code regulations with regards to openings in CLT panels. In this study, six 5-layer CLT panels containing different openings were tested. The parameters considered include the size and layout of the opening. The panels were specifically designed with openings that would render them ineffective in resisting lateral loads according to the Japanese standard. However, in addition to the six panels, one panel without openings and one panel with openings that meet the Japanese standard was designed. All the CLT panels were tested in uniaxial diagonal compression in order to simulate pure shear loading. The CLT panels and the loading setup were designed such that the resulting failure mode will be governed by a shear mechanism. The main focus of the experiment was to relate the deterioration of the lateral strength and stiffness of the panels to the size and layout of the opening. The results showed that the panels with openings with the same area have relatively different failure direction and reduction factors for panel shear strength and stiffness, and that is due to the shear weak and strong direction that CLT panels have. Also, the effect of openings on the reduction of stiffness for CLT panels was found to be greater than their effect on the reduction of shear strength. The prescribed equation in the Japanese CLT Guidebook underpredicts stiffness reduction, and has discrepancies with regard to strength as the difference of panel strengths in weak and strong directions are not considered.
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15 records – page 1 of 2.