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14 records – page 1 of 2.

Bending Tests on Glulam-CLT Beams connected with Double-Sided Punched Metal Plate Fasteners and Inclined Screws

https://research.thinkwood.com/en/permalink/catalogue320
Year of Publication
2015
Topic
Connections
Mechanical Properties
Material
CLT (Cross-Laminated Timber)
Glulam (Glue-Laminated Timber)
Application
Beams
Floors
Author
Jacquier, Nicolas
Organization
Luleå University of Technology
Year of Publication
2015
Format
Report
Material
CLT (Cross-Laminated Timber)
Glulam (Glue-Laminated Timber)
Application
Beams
Floors
Topic
Connections
Mechanical Properties
Keywords
Bending Test
Shear Connections
Double-sided Punched Metal Plate
Inclined Screws
Research Status
Complete
Summary
This report presents bending tests performed on composite beams made from glulam beams and cross laminated timber (CLT) panels. The composite beam, with a T-cross section, represents a section of a floor element in a multi-storey CLT construction system. The shear connections used were made either of doublesided punched metal plate fasteners, either of inclined screws, or of a combination of both fastener types. The screws are used to secure the shear connection with double-sided nail plates with respect to possible separation forces between the glulam and the CLT. An additional test with a screw glued connection was made for comparison as the upper bound case in terms of composite action. The results show the beams with double-sided nail plates (with or without screws) achieved a very high level of composite action and an overall satisfactory behaviour. Almost full composite action was achieved for the screw-glued composite beam. A detailed design example of the beam element according to the Eurocode 5 and Finnish National Annex is presented.
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Development and Evaluation of Mechanical Joints for Composite Floor Elements with Cross Laminated Timber

https://research.thinkwood.com/en/permalink/catalogue208
Year of Publication
2015
Topic
Connections
Mechanical Properties
Material
CLT (Cross-Laminated Timber)
Glulam (Glue-Laminated Timber)
Timber-Concrete Composite
Application
Floors
Author
Jacquier, Nicolas
Organization
Luleå University of Technology
Year of Publication
2015
Format
Thesis
Material
CLT (Cross-Laminated Timber)
Glulam (Glue-Laminated Timber)
Timber-Concrete Composite
Application
Floors
Topic
Connections
Mechanical Properties
Keywords
Fasteners
Metal Plate
Strength
Stiffness
Double-sided Nail Plates
Research Status
Complete
Summary
This thesis focuses on the development of composite floor solutions where Cross Laminated Timber (CLT) panels are used as a base element. Preliminary investigations on shear connections between prefabricated concrete beams and CLT panels were performed. The focus is on investigations on glulam-CLT composite beam elements, and the mechanical shear connectors used to achieve composite action. The new shear connections system evaluated in this thesis for glulam-CLT floor elements consists of double-sided punched metal plate fasteners. In order to secure the shear connection made with double-sided nail plates and to improve the shear behaviour of the joint, a combination with inclined self-tapping screws was evaluated through a shear test programme. It was found that the double-sided punched metal plate fasteners and inclined screws can effectively be combined.
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Diaphragm shear and diagonal compression testing of cross-laminated timber

https://research.thinkwood.com/en/permalink/catalogue2858
Year of Publication
2021
Topic
Mechanical Properties
Material
CLT (Cross-Laminated Timber)
Application
Floors
Walls
Author
Sharifi, Jonas
Sharifi, Zahra
Berg, Sven
Ekevad, Mats
Organization
Luleå University of Technology
Publisher
Springer
Year of Publication
2021
Format
Journal Article
Material
CLT (Cross-Laminated Timber)
Application
Floors
Walls
Topic
Mechanical Properties
Keywords
Diagonal Compression Test
Diaphragm Shear Test
Shear Modulus
Research Status
Complete
Series
SN Applied Sciences
Summary
To learn the characteristics of a cross-laminated timber (CLT) panel, it is crucial to perform experimental tests. This study presents two experimental test methods to measure the in-plane shear modulus of CLT panels. This characteristic can be measured by multiple methods such as the picture frame test, the diagonal compression test, and the diaphragm shear test. In this study, the same CLT panels are tested and evaluated in the diaphragm shear test and the diagonal compression test to see if more reliable results can be achieved from the diaphragm shear test. This evaluation is done by experimental tests and finite element simulations. The theoretical pure shear simulation is used as a reference case. Finite element simulations are made for both edge glued and non-edge glued CLT panels. Nine CLT panels are tested in the diaphragm shear test and the diagonal compression test. During ideal conditions (uniform material properties and contact conditions), all three simulated methods result in an almost equal shear modulus. During the experimental testing, the diagonal compression test gives more coherent results with the expected shear modulus based on finite element simulations. Based on the diaphragm shear test results, the CLT panels behave like edge glued, but this situation is dismissed. However, during ideal conditions, the diaphragm shear test is seen as a more reliable method due to the higher proportion of shear in the measured area.
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Engineers’ Views on Serviceability in Timber Buildings

https://research.thinkwood.com/en/permalink/catalogue858
Year of Publication
2015
Topic
Serviceability
Application
Wood Building Systems
Author
Näslund, Ida
Organization
Luleå University of Technology
Year of Publication
2015
Format
Report
Application
Wood Building Systems
Topic
Serviceability
Keywords
Stabilisation
Stiffness
Deformation
Serviceability Limit State
Mid-Rise
Dynamic Properties
Research Status
Complete
Summary
Higher timber buildings are produced around the world. The interest for higher timber buildings has increased. Design in ultimate limit state is well known, but little focus has been put on serviceability limit state especially on higher timber buildings. In this report result from interviews with structural engineers/designers, timber frame suppliers, and development managers are presented. The focus has been on serviceability limit state in mid-rise timber buildings. The experience and knowledge with the respondents varies, which has given a wide perspective of the area
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Experimental Analysis of Passively and Actively Reinforced Glued-laminated Timber with Focus on Ductility

https://research.thinkwood.com/en/permalink/catalogue2823
Year of Publication
2021
Topic
Mechanical Properties
Material
Glulam (Glue-Laminated Timber)
Application
Beams
Author
Livas, Charalampos
Ekevad, Mats
Öhman, Micael
Organization
Luleå University of Technology
Publisher
Taylor&Francis Online
Year of Publication
2021
Format
Journal Article
Material
Glulam (Glue-Laminated Timber)
Application
Beams
Topic
Mechanical Properties
Keywords
Reinforcement
Ductility
Bending Test
Steel
Research Status
Complete
Series
Wood Material Science & Engineering
Summary
When glued-laminated timber are subjected to bending moment, they usually fail in a brittle way in the tension zone before the compressive zone reaches the compressive strength of wood. This means that the compression strength of wood is not fully exploited. By reinforcing the tension zone, the failure mode of glued-laminated timber can be changed from tensile to compressive. As a result, by utilizing the higher compressive strength, reinforced glued-laminated timber become stronger and the failure mode becomes compressive and ductile. This paper presents experimental results of the effect of steel reinforcements in the tension zone of glued-laminated timber. Four passively reinforced beams, four actively reinforced beams, and seven unreinforced beams were tested to failure in four-point bending tests. The experimental results confirmed the brittle tension failure in the unreinforced beams as well as the ductile and compressive failure in the reinforced beams. Furthermore, the experiments revealed the increase of the passively and the actively reinforced glued-laminated timber relative to the reference beams for strengths (26% and 39%) and stiffnesses (30% and 11%). Ductilities were increased from 7.7% for the reference beams to 90% and 75% for the passively and the actively reinforced glued-laminated timber, respectively.
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Experimental Testing of Anchoring Devices for Bottom Rail in Partially Anchored Timber Frame Shear Walls with Two-Sided Sheathing

https://research.thinkwood.com/en/permalink/catalogue400
Year of Publication
2012
Topic
Connections
Material
Light Frame (Lumber+Panels)
Application
Shear Walls
Author
Caprolu, Giuseppe
Organization
Luleå University of Technology
Year of Publication
2012
Format
Report
Material
Light Frame (Lumber+Panels)
Application
Shear Walls
Topic
Connections
Keywords
Failure Modes
Sheathing
Research Status
Complete
Summary
Källsner and Girhammar [1] have presented a new plastic design method for wood-framed shear walls at ultimate limit state. This method allows the designer to calculate the load-carrying capacity of shear walls partially anchored, where the leading stud is not fully anchored against uplift. The parameters varied are the size of the washer and the orientation of the pith. The bottom rail was subjected to loading perpendicular to grain through two-sided sheathing. In this report the different set of series are presented. Five sets were conducted depending on the size of the washer and in each set the pith was placed upwards and downwards.
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Experimental Testing of Hold Down Devices for Timber Frame Shear Walls

https://research.thinkwood.com/en/permalink/catalogue401
Year of Publication
2012
Topic
Connections
Material
Light Frame (Lumber+Panels)
Application
Shear Walls
Author
Caprolu, Giuseppe
Organization
Luleå University of Technology
Year of Publication
2012
Format
Report
Material
Light Frame (Lumber+Panels)
Application
Shear Walls
Topic
Connections
Keywords
Hold-Down
Strength
Stiffness
Research Status
Complete
Summary
Källsner and Girhammar [1] have presented a new plastic design method for wood-framed shear walls at ultimate limit state. This method allows the designer to calculate the load-carrying capacity of partially anchored shear walls, where the leading stud is not anchored against uplift. In this report hold downs have been experimentally studied with respect to the strength and stiffness of the connection. Four different types of hold downs have been tested. The specimen was subjected to tension load applied to the stud. Four tests series are presented. Each series was divided into different sets according to the type of fastener used with the hold down device. The results show that the failure load is higher when hold downs with anchor bolts are used, up to ten times higher than the anchorage that uses only screws or nails. The failure mode vary with the type of hold down and the type of fasteners used. The tests showed three primary failure modes: failure of the stud when a bolt is used as the fastener between hold down device and stud, failure due to pull-out of the screws or nails from the rail and failure due to failure or pull-out of screws or nails from stud. Also, failure of the stud itself occurred in some tests caused by some defect of the timber.
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Feasibility of portable NIR spectrometer for quality assurance in glue-laminated timber production

https://research.thinkwood.com/en/permalink/catalogue2962
Year of Publication
2021
Topic
Mechanical Properties
Material
Glulam (Glue-Laminated Timber)
Author
Sandak, Jakub
Niemz, Peter
Hänsel, Andreas
Mai, Juana
Sandak, Anna
Organization
University of Primorska
ETH Zurich
Bern University of Applied Sciences
Luleå University of Technology
Saxon University of Cooperative Education
Publisher
Elsevier
Year of Publication
2021
Format
Journal Article
Material
Glulam (Glue-Laminated Timber)
Topic
Mechanical Properties
Keywords
Near Infrared Spectroscopy
Delamination
Quality Assurance
Research Status
Complete
Series
Construction and Building Materials
Summary
The feasibility of a portable NIR sensor for off-line determination of diverse wood quality aspects relevant in the production of glue-laminated timber was demonstrated. The best performance was noticed for assessing wood moisture content, with a lower capacity to estimate wood density and mechanical properties. NIR spectroscopy was modestly capable of predicting surface roughness. However, the traceability of the raw resources and the automatic classification of diverse wood defects were successfully demonstrated. The developed chemometric model could predict the total delamination and detailed delamination length. Finally, recommendations regarding further system development were provided with the aim of implementation and integration of the NIR measurement into glue-laminated timber production plants.
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Finite element analysis of alternative load paths to prevent disproportionate collapse in platform-type CLT floor systems

https://research.thinkwood.com/en/permalink/catalogue2901
Year of Publication
2021
Topic
Design and Systems
Material
CLT (Cross-Laminated Timber)
Application
Floors
Author
Huber, Johannes
Bita, Hercend
Tannert, Thomas
Berg, Sven
Organization
Luleå University of Technology
University of Northern British Columbia
Publisher
Elsevier
Year of Publication
2021
Format
Journal Article
Material
CLT (Cross-Laminated Timber)
Application
Floors
Topic
Design and Systems
Keywords
Mass Timber
Structural Robustness
High Fidelity Model
Progressive Collapse
Structural Integrity
Component Model
Research Status
Complete
Series
Engineering Structures
Summary
Multi-storey buildings require mitigation of consequences of unexpected or accidental events, to prevent disproportionate collapse after an initial damage. Cross-laminated timber (CLT) in platform-type construction is increasingly used for multi-storey buildings, however, the collapse behaviour and alternative load paths (ALPs) are not fully understood. A 3D non-linear component-based finite element model was developed for a platform-type CLT floor system to study the ALPs after an internal wall loss, in a pushdown analysis. The model, which accounted for connection failure, timber crushing and large displacements, was calibrated to experimental results and then adapted for boundary conditions corresponding to typical residential and office buildings. Subsequently, five parameters (floor span, connection type, vertical location of the floor, tying level, horizontal wall stiffness) were varied, to study their effects on the ALPs in 80 models. The results showed that three ALPs occurred, of which catenary action was the most dominant. Collapse resistance was mainly affected by the floor span, followed by the axial strength, stiffness and ductility of the floor-to-floor connection, the weight of the level above and the floor panel thickness. This study provides an approach to model ALPs in a platform-type CLT floor system to design disproportionate collapse resistant multi-storey CLT buildings.
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From file to factory: Innovative design solutions for multi-storey timber buildings applied to project Zembla in Kalmar, Sweden

https://research.thinkwood.com/en/permalink/catalogue3055
Year of Publication
2019
Topic
Design and Systems
Author
Kaiser, Alex
Larsson, Magnus
Girhammar, Ulf Arne
Organization
Luleå University of Technology
Publisher
Elsevier
Year of Publication
2019
Format
Journal Article
Topic
Design and Systems
Keywords
Multi-Storey Timber Building
File-to-factory
Modular Systems
Grid Shells
Slotting
Living Capsules
Research Status
Complete
Series
Frontiers of Architectural Research
Summary
A “file-to-factory” process of computer technology is a way to both maximise efficiency throughout the building process, increase a building s performance, and be able to add interesting architectural possibilities throughout the design phase. The authors investigate a novel approach that produces a set of building trajectories rather than a set of buildings, yet yields a series of build-able examples of those trajectories. This paper evaluates how this series of stacked multi-storey timber buildings can be both incorporated within a file-to-factory process, and give rise to creating new innovative solutions throughout the entire design and manufacturing process. This process is applied to a real Swedish project called Zembla. It redefines the notion of sprawl, turning it into a progressive tactics for linking the city fabric to rural areas. It is a post-sustainable file-to-factory-produced timber ground-scraper; soaring above ground and water, suggesting a new way of making city-sized buildings for the future. A plug-in grid-shell structure is designed to contain a minimal amount of timber elements, beams make up the lattice, cross-laminated panels add structural support, surfaces come together to form the living capsules. Having the structure undulate across the topography and touching the ground in as few places as possible uses the dichotomy between landscape and urbanism, bringing the city to the people living in less densified areas. Each living unit is customised to its topological conditions within the grid.
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14 records – page 1 of 2.