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An Experimental Study on Buckling Strength with Laminated Veneer Lumber of Three Wood Species

https://research.thinkwood.com/en/permalink/catalogue1575
Year of Publication
2016
Topic
Mechanical Properties
Material
LVL (Laminated Veneer Lumber)
Author
Kambe, Wataru
Nakamura, Madoka
Year of Publication
2016
Format
Conference Paper
Material
LVL (Laminated Veneer Lumber)
Topic
Mechanical Properties
Keywords
Japanese Larch
Japanese Cypress
Japanese Cedar
Compression Test
Deflection
Strain
Buckling Strength
Slenderness Ratio
Bending Deflection
Maximum Strength
Yield Strength
Conference
World Conference on Timber Engineering
Research Status
Complete
Notes
August 22-25, 2016, Vienna, Austria p. 1698-1706
Summary
In the past study, we conducted compression tests with laminated veneer lumber of Japanese Larch. We observed the deflection and strain behaviour. As a result we could evaluate the bucking strength with Euler’s equation and Tetmajer’s method. For structural design we should expand the versatility of that method. Three wood species for structural members would be selected for these tests. Those were Japanese larch, Japanese cypress and Japanese cedar. For the test parameter, we set the 8types of slenderness ratio for the compression test and we conducted monotonic compression tests with pin-supported on both edges. For the mechanical properties we conducted compression tests with short column members and got yield compression for those materials. In the compression tests, we could see the bending deflection. We would get the ratio the maximum strength and yield strength for distinguish the limited slenderness ratio. As a result it was cleared that the limit slenderness ratio of these wood species was 100. And we could confirm that the Tetmajer’s method is useful for evaluation the yield strength.
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The Bending-Gradient Theory for the Linear Buckling of Thick Plates: Application to Cross-Laminated-Timber Panels

https://research.thinkwood.com/en/permalink/catalogue851
Year of Publication
2016
Topic
Mechanical Properties
Material
CLT (Cross-Laminated Timber)
Author
Perret, Olivier
Lebée, Arthur
Douthe, Cyril
Sab, Karam
Publisher
ScienceDirect
Year of Publication
2016
Format
Journal Article
Material
CLT (Cross-Laminated Timber)
Topic
Mechanical Properties
Keywords
Bending-Gradient theory
Linear Buckling
Critical Load
Research Status
Complete
Series
International Journal of Solids and Structures
Summary
In this paper, the linear buckling of a heterogeneous thick plate is studied using the Bending–Gradient theory which is an extension of the Reissner–Mindlin plate theory to the case of heterogeneous plates. Reference results are taken from a 3D numerical analysis using finite-elements and applied to Cross Laminated Timber panels which are thick and highly anisotropic laminates. First, it is shown that critical buckling loads are close to the material failure load which proves the necessity of a design model for the buckling of Cross Laminated Timber panels. Second, the soft simple support boundary condition is introduced as an opposition to the conventional hard simple support condition. It is shown that this distinction could be taken into account for designing timber structures depending on the accuracy needed. Third, it is observed that for varying plate geometries and arrangements, the Bending–Gradient theory predicts more precisely the critical load of CLT panels than classical lamination and first-order shear deformation theories. Finally, it is demonstrated that one of the suggested projections of the Bending–Gradient on a Reissner–Mindlin model gives very accurate results and could favorably allow the development of engineering recommendations for estimating properly transverse shear effects.
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Bending Tests with Glulam Columns under Eccentric Normal Force Stress

https://research.thinkwood.com/en/permalink/catalogue1138
Year of Publication
2015
Topic
Mechanical Properties
Material
Glulam (Glue-Laminated Timber)
Author
Frangi, Andrea
Theiler, Matthias
Organization
ETH Zurich
Year of Publication
2015
Format
Thesis
Material
Glulam (Glue-Laminated Timber)
Topic
Mechanical Properties
Keywords
Load Bearing Capacity
Axial Compression
Buckling Tests
Spruce
Research Status
Complete
Summary
The force-displacement behaviour of structural timber members subjected to axial compression or combined axial compression and bending is distinctively non-linear. This behaviour is caused by the non-linear increase of the deformation due to the increasing eccentricity of the axial load as well as by the non-linear material behaviour of timber when subjected to compression. The present report describes experimental investigations on glued laminated timber members subjected to eccentric compression. The aim of these experimental investigations was to create a data base, which can be used to validate theoretical calculation models and to assess the accurateness of the design approaches given in the design codes for timber structures. The specimens for the main bunch of experiments were produced using lamellas made of Norway spruce grown in Switzerland. For this purpose, a total of 336 lamellas were available. In the first step, non-destructive tests on the lamellas were performed. These tests aimed at the collection of data in order to characterise the raw material. In the second step, the lamellas were strength graded. The aim of the grading process was to select two classes of lamellas for the production of the test specimens. The lamellas were selected so that they were suitable to produce glued laminated timber of strength classes GL24h and GL32h. Within the grading process, visual grading criteria as well as machine grading criteria were used. In the third step, the graded lamellas were used to produce glued laminated timber members. Five tests series were produced. Each of the test series consisted of ten specimens. Three series were made of glued laminated timber GL24h and two series were made of glued laminated timber GL32h. The length of the timber members was varied between the different test series. The lengths were L = 1’400 mm, L = 2’300 mm and L = 3’200 mm respectively. During the production, the setup of the test specimens was recorded. Hence, the position and the orientation of every lamella within the test specimen were documented. Additionally, some non-destructive tests were performed using the test specimens. In the last step, the glued laminated timber members were subjected to buckling tests. The test specimens were loaded with an eccentric compression force up to failure. During the tests, different measurements were carried out in order to document the experimental investigations as accurate as possible. Amongst others, the applied loads as well as horizontal and vertical deformations were recorded. For a subsample of 20 test specimens, additional local deformation measurements were performed using an optical measurement device.
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Buckling of Cross Laminated Timber Walls

https://research.thinkwood.com/en/permalink/catalogue1615
Year of Publication
2016
Topic
Mechanical Properties
Material
CLT (Cross-Laminated Timber)
Application
Walls
Author
Perret, Olivier
Douthe, Cyril
Lebée, Arthur
Sab, Karam
Year of Publication
2016
Format
Conference Paper
Material
CLT (Cross-Laminated Timber)
Application
Walls
Topic
Mechanical Properties
Keywords
Linear Buckling
Finite Element
Buckling Loads
Boundary Conditions
Bending-Gradient theory
Transverse Shear Effects
Conference
World Conference on Timber Engineering
Research Status
Complete
Notes
August 22-25, 2016, Vienna, Austria p. 2360-2367
Summary
In this paper, the linear buckling of Cross Laminated Timber walls is investigated. A 3D numerical study using finite-elements is presented for several Cross Laminated Timber geometries, ply configurations and boundary conditions. First, it is shown that critical buckling loads are close to the material failure load which proves the necessity of a design model for the buckling of Cross Laminated Timber panels. Second, through a comparison between soft simple support boundary conditions and conventional hard simple support conditions, it is shown that this distinction could be taken into account for designing timber structures depending on the accuracy needed. Third, several plate models, particularly the Bending-Gradient theory, are compared to these 3D reference results. It is observed that for varying plate geometries and arrangements, the Bending-Gradient theory predicts more precisely the critical load of CLT panels than classical lamination and first-order shear deformation theories. Finally, it is demonstrated that one of the suggested projections of the Bending-Gradient on a Reissner-Mindlin model gives very accurate results and could favorably allow the development of engineering recommendations to estimate properly transverse shear effects.
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Buckling-restrained Braced Frames for Seismically Resilient Mass Timber Buildings

https://research.thinkwood.com/en/permalink/catalogue2571
Topic
Seismic
Wind
Application
Frames
Organization
University of Utah
Application
Frames
Topic
Seismic
Wind
Keywords
Buckling Restrained Brace Frames
Resilient Building Design
Mass Timber
Energy Dissipation
Monitoring
Research Status
In Progress
Notes
Project contact is Chris Pantelides at the University of Utah
Summary
A mass timber buckling-restrained braced frame is proposed to enhance the seismic resilience of mass timber buildings. Constructed using wood generated from the national forest system, the mass timber buckling-restrained brace will be integrated with a mass timber frame for structural energy dissipation under seismic or wind loads. The team will improve and optimize the design of structural components based on feedback from a real-time health monitoring system. Outcomes include guidelines for a lateral force resisting system of mass timber buildings in high seismic or wind regions.
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Comparing Numerical Results for Seismic Performance of Portal Steel Frames Braced with Steel: HSS Brace, Glulam Timber Brace, and Timber-Steel-BRB

https://research.thinkwood.com/en/permalink/catalogue3163
Year of Publication
2022
Topic
Seismic
Material
Glulam (Glue-Laminated Timber)
Application
Frames
Author
Sabbagh-Yazdi, Saeed-Reza
Mirzazadah, Ainullah
Organization
Toosi University of Technology
Editor
Branco, Jorge
Publisher
Hindawi
Year of Publication
2022
Format
Journal Article
Material
Glulam (Glue-Laminated Timber)
Application
Frames
Topic
Seismic
Keywords
Portal Steel Frames
Seismic Analyses
Buckling Restrained Brace
Energy Dissipation
Research Status
Complete
Series
Advances in Civil Engineering
Summary
This study involves the application of timber-based bracings elements. For this purpose, seismic analyses are performed on special portal steel frames without the brace and diagonally braced with Glued Laminated Timber (glulam) and Timber-Steel Buckling Restrained Brace (TS-BRB), and the results are compared with the same configuration using steel Hollow Structural Sections (HSS) bracing, using OpenSees structural analyzer. First, to verify the accuracy of the modeling, the numerical results are compared with experimental measurements on several types of elements: (a) diagonally braced frame with steel Hollow Structural Sections with a concentrically steel braced frame which was tested by the quasi-static method under cyclic loading protocol by previous researchers, (b) diagonally glulam braced frame with results of shake table tests on single-story timber braced frames, and (c) Timber-Steel Buckling Restrained Brace (TS-BRB) frame with experimental results of Heavy Timber Buckling-Restrained Braced Frame (HT-BRB). In the second step, the aforementioned timber base bracing alternatives (glulam, TS-BRB) are applied in the special portal steel frame, then the seismic performance of the frame is investigated under pushover, cyclic, time history, and incremental dynamic analysis (IDA), and then the results are compared with the behavior of similar portal frame in two conditions without the brace and diagonally braced with the steel-HSS brace. Results showed that steel-HSS, glulam, and timber-steel buckling restrained braces have significant roles in energy dissipation, increasing shear capacity, decreasing interstory drift, and decreasing weight and cost of estimation of the structure.
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Design of Timber Members Subjected to Axial Compression or Combined Axial Compression and Bending Based on 2nd Order Theory

https://research.thinkwood.com/en/permalink/catalogue115
Year of Publication
2015
Topic
Design and Systems
Mechanical Properties
Material
Glulam (Glue-Laminated Timber)
Application
Columns
Author
Frangi, Andrea
Steiger, René
Theiler, Matthias
Organization
International Network on Timber Engineering Research (INTER)
Year of Publication
2015
Format
Conference Paper
Material
Glulam (Glue-Laminated Timber)
Application
Columns
Topic
Design and Systems
Mechanical Properties
Keywords
Bending
Buckling
Codes
Compression
Deformation
Monte Carlo
Simulation
Structural
Testing
Conference
INTER 2015
Research Status
Complete
Notes
August 24-27, 2015, Sibenik, Croatia
Summary
The paper examines the behaviour of structural timber members subjected to axial compression or combined axial compression and bending. Based on experimental and numerical investigations, the accuracy of the existing approach in Eurocode 5 for the design of timber members subjected to axial compression or combined axial compression and bending is assessed and modifications are suggested. By means of extensive experimental investigations, a data base was created for the validation of calculation models and for the assessment of design concepts. In order to assess the behaviour of timber members subjected to axial compression or combined axial compression and bending, strain-based calculation models were developed. The investigations indicate that the existing approach of Eurocode 5 based on 2nd order analysis can lead to an overestimation of the load-bearing capacity. Hence, a modified design approach was developed which agrees with the results of the Monte Carlo simulations very well and thus ensures a safe and economical design of timber members subjected to compression or combined compression and bending.
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Development of Timber Buckling-Restrained Braces for Mass Timber Braced Frames

https://research.thinkwood.com/en/permalink/catalogue2199
Year of Publication
2019
Topic
Seismic
Material
LVL (Laminated Veneer Lumber)
PSL (Parallel Strand Lumber)
Glulam (Glue-Laminated Timber)
MPP (Mass Plywood Panel)
Application
Wood Building Systems
Author
Murphy, Colton
Pantelides, Chris
Blomgren, Hans-Erik
Rammer, Douglas
Year of Publication
2019
Format
Conference Paper
Material
LVL (Laminated Veneer Lumber)
PSL (Parallel Strand Lumber)
Glulam (Glue-Laminated Timber)
MPP (Mass Plywood Panel)
Application
Wood Building Systems
Topic
Seismic
Keywords
Lateral Force Resisting System
Buckling Restrained Brace Frames
Conference
INTER
Research Status
Complete
Summary
Buckling Restrained Brace Frames (BRBF) are a proven and reliable method to provide an efficient lateral force resisting system for new and existing structures in earthquake prone regions. The fuse-type elements in this system facilitate stable energy dissipation at large load deformation levels. Currently, the new trend towards mass timber vertical...
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Development of Timber Buckling Restrained Braces for Mass Timber Braced Frames

https://research.thinkwood.com/en/permalink/catalogue2544
Year of Publication
2019
Topic
Seismic
Design and Systems
Application
Frames
Author
Murphy, Colton
Pantelides, Chris
Blomgren, Hans-Erik
Rammer, Douglas
Year of Publication
2019
Format
Conference Paper
Application
Frames
Topic
Seismic
Design and Systems
Keywords
Brace
Buckling
Damping
Fuse
Seismic
Structure
Timber
Conference
International Network on Timber Engineering Research
Research Status
Complete
Summary
Buckling Restrained Brace Frames (BRBF) are a proven and reliable method to provide an efficient lateral force resisting system for new and existing structures in earthquake prone regions. The fuse-type elements in this system facilitate stable energy dissipation at large load deformation levels. Currently, the new trend towards mass timber vertical structures creates a need for a lightweight compatible lateral force resisting system. A Buckling Restrained Brace (BRB) component is possible to construct and feasible to implement when combining a steel core with a mass timber casing herein named the Timber-Buckling Restrained Brace (T-BRB). T-BRBs when combined with mass timber beam and column elements can create a system that will have advantages over the current steel framed BRBF system when considering recyclability, sustainability, framing compatibility, and performance. This paper presents findings on small scale testing of candidate engineered wood products for the T-BRB casing and testing of six full scale 12 ft long 60 kip braces according to code prescribed loading protocols and acceptance criteria.
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Discrete Bracing of Timber Beams Subjected to Gravity Loads

https://research.thinkwood.com/en/permalink/catalogue683
Year of Publication
2014
Topic
Mechanical Properties
Material
Glulam (Glue-Laminated Timber)
Application
Beams
Author
Klasson, Anders
Crocetti, Roberto
Hansson, Eva
Year of Publication
2014
Format
Conference Paper
Material
Glulam (Glue-Laminated Timber)
Application
Beams
Topic
Mechanical Properties
Keywords
Gravity Loads
Buckling Strength
Brace Forces
Conference
World Conference on Timber Engineering
Research Status
Complete
Notes
August 10-14, 2014, Quebec City, Canada
Summary
Slender timber beams subjected to gravity loads may buckle in the out-of-plane direction. Normally, the same bracing system that is used to prevent lateral movements of the beams, caused by external transversal loading, also serve to increase the buckling strength of the beams. For the idealized case of a perfectly straight beam with full-bracing there is no force in the braces even at buckling because there is no displacement at the brace points. However, in real beams brace forces do develop during loading. This paper describes experimental and analytical studies performed on slender glulam beams subjected to gravity loads laterally stiffened by means of discrete bracing. In particular, the influence of relevant parameters such as i) brace stiffness, ii) brace position, iii) shape and magnitude of initial imperfections on the brace force were investigated.
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20 records – page 1 of 2.