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38 records – page 1 of 4.

The Analysis of Bending Stiffness and Strength of Glue Laminated Nigerian Timber

https://research.thinkwood.com/en/permalink/catalogue2579
Year of Publication
2020
Topic
Mechanical Properties
Material
Glulam (Glue-Laminated Timber)
Author
Okafor, Kingsley
Ezeagu, Celestine
Publisher
Europa Publishing
Year of Publication
2020
Format
Journal Article
Material
Glulam (Glue-Laminated Timber)
Topic
Mechanical Properties
Keywords
Flexural Strength
Polyurethane
PUR
Adhesive
Timber
Research Status
Complete
Series
European Journal of Engineering Research & Science
Summary
An analysis into the flexural strength of solid and laminated timber specimens under working conditions was conducted. Five hardwoods and five softwoods were investigated, namely: Mansonia, Mahogany, Orji, Ukpi, Ufi mmanu, White Afara, Owen, Melina, Akpu and Ubia. The dimensions of the wood specimens are 100mm×50mm×20mm. The wood samples were tested for flexural strength using a Universal Testing Tensile Machine. The results obtained shows that Owen has the highest ultimate wood strength of 46.806N/mm² for the softwood glulam. Ukpi has the highest wood strength of 73.375N/mm² for the hardwood glulam, and highest MOE at 2412.93N/mm². Akpu recorded the weakest sample with bending strength values for glulam at 11.929 N/mm². Comparisons of strength were made to their respective solid timbers. Failure modes were analyzed. The study therefore demonstrates that the timber species used can be engineered to load bearing glulam structural elements using polyurethane adhesive glue without severe loss of strength.
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Comparison of Various Glulam in Physical Properties and Flexural Behaviors

https://research.thinkwood.com/en/permalink/catalogue642
Year of Publication
2013
Topic
Mechanical Properties
Material
Glulam (Glue-Laminated Timber)
Author
Qiu, Jing
Tong, Jianhong
Hui Chen, Li
Publisher
Scientific.net
Year of Publication
2013
Format
Journal Article
Material
Glulam (Glue-Laminated Timber)
Topic
Mechanical Properties
Keywords
Douglas-Fir
Flexural Behavior
Physical Properties
Larch
Modulus of Rupture
Pine
Poplar
Research Status
Complete
Series
Applied Mechanics and Materials
Summary
The glulam is determined by, and therefore a representation of, a new kind of ecological structural materials. The aim of this study was to summarize the mechanical performance especially the flexural behavior of various kinds of glulam and the physical properties of their relevant original timbers including pseudotsuga menziesii, larch, Yi poplar, poplar, China fir, mongolian scotch pine and camphor. And then it established and analyzed the relationship between the two to contrast those timber species so as to provide engineers with some reference in selecting timber glulam.
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Cross Laminated Timber Reinforced with Carbon Fibre

https://research.thinkwood.com/en/permalink/catalogue2661
Topic
Mechanical Properties
Material
CLT (Cross-Laminated Timber)
Author
Cao, Xinlei
Organization
University of Alberta
Material
CLT (Cross-Laminated Timber)
Topic
Mechanical Properties
Keywords
Carbon Fiber
Flexural Stiffness
Stress Distribution
Analytical Model
Finite Element Method (FEM)
Research Status
In Progress
Summary
Although engineered wood products such as glued laminated timber (glulam) and cross-laminated timber (CLT) have successfully eliminated the flaws inherently exist in conventional wood products, they are still not comparable with steel and concrete in terms of strength and stiffness. Among all different options for reinforcement, Carbon Fibre is relatively popular due to its high tensile strength, low weight, and easy installation. This study presents an analysis of flexural stiffness and stress distributions of CLT panels reinforced with carbon fibre mats, based on an analytical method and finite element method (FEM).
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Design Methodology Analysis of Cross-Laminated Timber Elements Subjected to Flexure

https://research.thinkwood.com/en/permalink/catalogue7
Year of Publication
2014
Topic
Mechanical Properties
Material
CLT (Cross-Laminated Timber)
Application
Ceilings
Floors
Walls
Author
Vilguts, Aivars
Serdjuks, Dmitrijs
Mierinš, Imants
Publisher
Kaunas University of Technology
Year of Publication
2014
Format
Journal Article
Material
CLT (Cross-Laminated Timber)
Application
Ceilings
Floors
Walls
Topic
Mechanical Properties
Keywords
Design
Flexural
FEM method
Testing
Panels
Research Status
Complete
Series
Journal of Sustainable Architecture and Civil Engineering
Summary
Cross-laminated timber is a structural material, which successfully used for structural purposes during the last years. The material is environmentally friendly and decreases CO2 emissions. Cross-laminated timber possesses a decreased level of anisotropy in comparison with solid and glued timber. It is significant for structural units working in bending. So, cross-laminated timber panels are considered as an object of investigation. Design methodology for cross-laminated timber panels subjected to flexure was presented. The methodology is based on LVS EN1995-1-1 and laminated plate theory. The presented methodology was tested experimentally and analytically. Behavior and mechanical properties of cross-laminated timber are analyzed for case of static loading. Two panels with thickness 95mm consisting from three layers were tested in laboratory. Freely supported panels with span equal to 2m, which is loaded by the uniformly distributed load was a design scheme of considered panels. The panel’s width was equal to 1m. Analytical FEM design method, which is based on the using of computational program ANSYSv14 and RFEM5.0, was checked by the experiment. The comparison of stresses acting in the edge fibers and vertical displacements shows that the considered design methodology can be used for engineering calculations. The result difference changes in limits to 30%.
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The Design of a Semi-Prefabricated LVL-Concrete Composite Floor

https://research.thinkwood.com/en/permalink/catalogue103
Year of Publication
2012
Topic
Design and Systems
Material
LVL (Laminated Veneer Lumber)
Timber-Concrete Composite
Application
Floors
Author
Yeoh, David
Fragiacomo, Massimo
Publisher
Hindawi Publishing Corporation
Year of Publication
2012
Format
Journal Article
Material
LVL (Laminated Veneer Lumber)
Timber-Concrete Composite
Application
Floors
Topic
Design and Systems
Keywords
Flexural Stiffness Method
Prefabrication
Research Status
Complete
Series
Advances in Civil Engineering
Summary
This paper describes the design of a novel semi-prefabricated LVL-concrete composite floor that has been developed in New Zealand. In this solution, the floor units made from LVL joists and plywood are prefabricated in the factory and transported to the building site. The units are then lifted onto the supports and connected to the main frames of the building and to the adjacent units. Finally, a concrete topping is poured on top of the units in order to form a continuous slab connecting all the units. Rectangular notches cut from the LVL joists and reinforced with coach screws provide the composite action between the concrete slab and the LVL joists. This system proved to be an effective modular solution that ensures rapid construction. A design procedure based on the use of the effective flexural stiffness method, also known as the “gamma method” is proposed for the design of the composite floor at ultimate and serviceability limit states, in the short and long term. By comparison with the experimental results, it is shown that the proposed method leads to conservative design. A step-by-step design worked example of this novel semi-prefabricated composite floor concludes the paper.
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Displacement Design Procedure for Cross Laminated Timber (CLT) Rocking Walls with Sacrificial Dampers

https://research.thinkwood.com/en/permalink/catalogue395
Year of Publication
2015
Topic
Design and Systems
Seismic
Material
CLT (Cross-Laminated Timber)
Application
Walls
Author
Gu, Mengzhe
Pang, Weichiang
Schiff, Scott
Organization
Structures Congress
Publisher
American Society of Civil Engineers
Year of Publication
2015
Format
Conference Paper
Material
CLT (Cross-Laminated Timber)
Application
Walls
Topic
Design and Systems
Seismic
Keywords
Energy Dissipation
Ductile Behavior
U-Shaped Flexural Plates
Self-centering Mechanism
Conference
Structures Congress 2015
Research Status
Complete
Notes
April 23–25, 2015, Portland, Oregon, USA
Summary
This paper presents the preliminary design of a rocking Cross-laminated Timber (CLT) wall using a displacement-based design procedure. The CLT wall was designed to meet three performance expectations: immediate occupancy (IO), life safety (LS), and collapse prevention (CP). Each performance expectation is defined in terms of an inter-story drift limit with a predefined non-exceedance probability at a given hazard level. U-shape flexural plates were used to connect the vertical joint between the CLT panels to obtain a ductile behavior and adequate energy dissipation during seismic motion. A design method for ensuring self-centering mechanism is also presented.
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Durability of Structural Lumber Products after Exposure at 82C and 80% Relative Humidity

https://research.thinkwood.com/en/permalink/catalogue784
Year of Publication
2005
Topic
Mechanical Properties
Moisture
Material
LSL (Laminated Strand Lumber)
LVL (Laminated Veneer Lumber)
Solid-sawn Heavy Timber
Author
Green, David
Evans, James
Hatfield, Cherilyn
Byrd, Pamela
Organization
Forest Products Laboratory
Year of Publication
2005
Format
Report
Material
LSL (Laminated Strand Lumber)
LVL (Laminated Veneer Lumber)
Solid-sawn Heavy Timber
Topic
Mechanical Properties
Moisture
Keywords
Aspen
Douglas-Fir
Modulus of Elasticity
Modulus of Rupture
Southern Pine
Poplar
Relative Humidity
SPF
Temperature
Flexural Properties
Research Status
Complete
Summary
Solid-sawn lumber (Douglas-fir, southern pine, Spruce– Pine–Fir, and yellow-poplar), laminated veneer lumber (Douglas-fir, southern pine, and yellow-poplar), and laminated strand lumber (aspen and yellow-poplar) were heated continuously at 82°C (180°F) and 80% relative humidity (RH) for periods of up to 24 months. The lumber was then reconditioned to room temperature at 20% RH and tested in edgewise bending. Little reduction occurred in modulus of elasticity (MOE) of solid-sawn lumber, but MOE of composite lumber products was somewhat reduced. Modulus of rupture (MOR) of solid-sawn lumber was reduced by up to 50% after 24 months exposure. Reductions in MOR of up to 61% were found for laminated veneer lumber and laminated strand lumber after 12 months exposure. A limited scope study indicated that the results for laminated veneer lumber in edgewise bending are also applicable to flatwise bending. Comparison with previous results at 82°C (180°F)/25% RH and at 66°C (150°F)/20% RH indicate that differences in the permanent effect of temperature on MOR between species of solid-sawn lumber and between solid-sawn lumber and composite lumber products are greater at high humidity levels than at low humidity levels. This report also describes the experimental design of a program to evaluate the permanent effect of temperature on flexural properties of structural lumber, with reference to previous publications on the immediate effect of temperature and the effect of moisture content on lumber properties.
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Effect of Notches on the Performance of Cross-Laminated Timber

https://research.thinkwood.com/en/permalink/catalogue2559
Topic
Mechanical Properties
Material
CLT (Cross-Laminated Timber)
Organization
Forest Products Laboratory
Mississippi State University
Material
CLT (Cross-Laminated Timber)
Topic
Mechanical Properties
Keywords
Notches
Notched Connections
Bending Properties
Flexural Properties
Research Status
In Progress
Notes
Project contacts are Robert J. Ross at the Forest Products Laboratory and Rubin Shmulsky at Mississippi State University
Summary
Notches, particularly when incorporated on the tensile face, influence the ultimate capacity of members, such as beams and floor panels. Understanding and quantification of failure modes, ductility, and strength of notched CLT floor panels can allow the safe application of notches on building construction. Despite wood’s ductility, notches are known areas of stress concentration. The 2018 International Residential Code for one- and two-family dwellings (International Code Council 2017) restricts the use of notches on engineered wood products by requiring structural calculations instead of elucidating the ways notches might be used. To employ CLT to its maximum potential, there is a current and pressing need for better knowledge regarding the influence of notches on flexural performance. This research seeks to review the literature regarding notches in solid and engineered beams, review typical CLT design details that employ or utilized notched panels, and conduct pilot-scale testing of notched CLT panels.
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Effects of Reinforcement Geometry on Strength and Stiffness in Adhesively Bonded Steel-Timber Flexural Beams

https://research.thinkwood.com/en/permalink/catalogue898
Year of Publication
2012
Topic
Mechanical Properties
Material
Steel-Timber Composite
Application
Beams
Author
Alam, Parvez
Ansell, Martin
Smedley, Dave
Publisher
MDPI
Year of Publication
2012
Format
Journal Article
Material
Steel-Timber Composite
Application
Beams
Topic
Mechanical Properties
Keywords
Finite Element Model
Yield Strength
Volume Fraction
Flexural Properties
Research Status
Complete
Series
Buildings
Summary
A finite element model is developed to analyse, as a function of volume fraction, the effects of reinforcement geometry and arrangement within a timber beam. The model is directly validated against experimental equivalents and found to never be mismatched by more than 8% in respect to yield strength predictions. Yield strength increases linearly as a function of increasing reinforcement volume fraction, while the flexural modulus follows more closely a power law regression fit. Reinforcement geometry and location of reinforcement are found to impact both the flexural properties of timber-steel composite beams and the changes due to an increase in volume fraction.
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Experimental Behaviour of Structural Size Glued Laminated Guadua Bamboo Members

https://research.thinkwood.com/en/permalink/catalogue528
Year of Publication
2014
Topic
Mechanical Properties
Material
Other Materials
Application
Beams
Columns
Author
Correal, Juan
Echeverry, Juan
Yamin, Luis
Ramírez, Fernando
Year of Publication
2014
Format
Conference Paper
Material
Other Materials
Application
Beams
Columns
Topic
Mechanical Properties
Keywords
Bending Strength
Flexural Tests
Compression Tests
Conference
World Conference on Timber Engineering
Research Status
Complete
Notes
August 10-14, 2014, Quebec City, Canada
Summary
This study presents the experimental evaluation of the behaviour of beams and columns made of Glued Laminated Guadua (GLG) bamboo. Flexural tests were conducted on structural size beams of various span lengths and two lamination orientations (horizontal and vertical) in order to evaluate the different capacities achieved according to the predominant induced stresses, bending or shear. Experimental results indicated a reduction of bending strength as the member’s size increased whereas lamination in the vertical direction presented 12% higher values of modulus of rupture (MOR), and 9% higher values of modulus of elasticity (MOE) compared to equivalent results for lamination in the horizontal direction. Additionally, compression tests were performed on structural size columns with various slenderness ratios and two lamination orientations. Although minor differences were found for lamination orientation, lower capacities were observed as the slenderness ratio increased. This experimental data is expected to be used in order to propose adjustment factors for structural size beams as well as the determination of the column stability factor.
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38 records – page 1 of 4.