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212 records – page 1 of 22.

Adhesive Bonding of Structural Hardwood Elements

https://research.thinkwood.com/en/permalink/catalogue75
Year of Publication
2015
Topic
Mechanical Properties
Serviceability
Moisture
Material
Glulam (Glue-Laminated Timber)
CLT (Cross-Laminated Timber)
Author
Hassani, Mohammad
Organization
ETH Zurich
Year of Publication
2015
Country of Publication
Switzerland
Format
Thesis
Material
Glulam (Glue-Laminated Timber)
CLT (Cross-Laminated Timber)
Topic
Mechanical Properties
Serviceability
Moisture
Keywords
Abaqus
Adhesives
Beech
Bonding
Delamination
Finite Element Model
Fracture
Long-term
Model
Hardwood
Language
English
Research Status
Complete
Summary
The current research investigated the delamination process of adhesively bonded hardwood (European beech) elements subject to changing climatic conditions. For the study of the long-term fracture mechanical behavior of gluedlaminated components under varying moisture content, the role of moisture development, time- and moisture-dependent responses are absolutely crucial. For this purpose, a 3D orthotropic hygro-elastic, plastic, visco-elastic, mechano-sorptive wood constitutive model with moisture-dependent material constants was presented in this work. Such a comprehensive material model is capable to capture the true historydependent stress states and deformations which are essential to achieve reliable design of timber structures. Besides the solid wood substrates, the adhesive material also influences the interface performance considerably. Hence, to gain further insight into the stresses and deformations generated in the bond-line, a general hygro-elastic, plastic, visco-elastic creep material model for adhesive was introduced as well. The associated numerical algorithms developed on the basis of additive decomposition of the total strain were formulated and implemented within the Abaqus Finite Element (FE) package. Functionality and performance of the proposed approach were evaluated by performing multiple verification simulations of wood components, under different combinations of mechanical loading and moisture variation. Moreover, the generality and efficiency of the presented approach was further demonstrated by conducting an application example of a hybrid wood element.
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Air-Borne Sound Transmission through Triple-Leaf Walls

https://research.thinkwood.com/en/permalink/catalogue2235
Year of Publication
2015
Topic
Acoustics and Vibration
Material
Light Frame (Lumber+Panels)
Application
Walls
Author
Eslami, Armin
Organization
Carleton University
Year of Publication
2015
Country of Publication
Canada
Format
Thesis
Material
Light Frame (Lumber+Panels)
Application
Walls
Topic
Acoustics and Vibration
Keywords
Mid-Rise
Airborne Sound
Model
Sound Transmission
Sound Insulation
Language
English
Research Status
Complete
Online Access
Free
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Air-Coupled Ultrasound Propagation and Novel Non-Destructive Bonding Quality Assessment of Timber Composites

https://research.thinkwood.com/en/permalink/catalogue13
Year of Publication
2012
Topic
Mechanical Properties
Material
Glulam (Glue-Laminated Timber)
Author
Martín, Sergio
Organization
ETH Zurich
Year of Publication
2012
Country of Publication
Switzerland
Format
Thesis
Material
Glulam (Glue-Laminated Timber)
Topic
Mechanical Properties
Keywords
Adhesives
Bonding
Delamination
Failure
Non-Destructive Testing
Air-coupled Ultrasound (ACU)
Finite-Difference Time-Domain (FDTD) model
Language
English
Research Status
Complete
Summary
Glued laminated timber (glulam) is manufactured by gluing and stacking timber lamellas, which are sawn and finger-jointed parallel to the wood grain direction. This results in a sustainable and competitive construction material in terms of dimensional versatility and load-carrying capacity. With the proliferation of glued timber constructions, there is an increasing concern about safety problems related to adhesive bonding. Delaminations are caused by manufacturing errors and in service climate variations simultaneously combined with long-sustained loads (snow, wind and gravel filling on flat roofs). Several recent building collapses were related to bonding failure, which should be prevented in the future with a timely defect detection. As an outlook, the feasibility of air-coupled ultrasound tomography was demonstrated with numerical tests and preliminary experiments on glulam. The FDTD wave propagation model was excited by the difference of the time-reversed sound fields transmitted through a test and a reference (defect-free) glulam cross-section. Both datasets were obtained with the same SLT setup. Wave convergences then provided a map of bonding defects along the height and width of the inspected glulam cross-sections. Further research is envisaged in this direction
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An Algorithm for Numerical Modelling of Cross-Laminated Timber Structures

https://research.thinkwood.com/en/permalink/catalogue2362
Year of Publication
2015
Topic
Design and Systems
Material
CLT (Cross-Laminated Timber)
Application
Wood Building Systems
Author
D'Aronco, Gabriele
Publisher
Università di Padova
Year of Publication
2015
Country of Publication
Italy
Format
Thesis
Material
CLT (Cross-Laminated Timber)
Application
Wood Building Systems
Topic
Design and Systems
Keywords
Connections
Panels
Model
Language
English
Research Status
Complete
Summary
Cross-laminated timber, also known as X-Lam or CLT, is well established in Europe as a construction material. Recently, implementation of X-Lam products and systems has begun in countries such as Canada, United States, Australia and New Zealand. So far, no relevant design codes for X-Lam construction were published in Europe, therefore an extensive research on the field of cross-laminated timber is being performed by research groups in Europe and overseas. Experimental test results are required for development of design methods and for verification of design models accuracy. This thesis is part of a large research project on the development of a software for the modelling of CLT structures, including analysis, calculation, design and verification of connections and panels. It was born as collaboration between Padua University and Barcelona"s CIMNE (International Centre for Numerical Methods in Engineering). The research project started with the thesis “Una procedura numerica per il progetto di edifici in Xlam” by Massimiliano Zecchetto, which develops a software, using MATLAB interface, only for 2D linear elastic analysis. Follows the phase started in March 2015, consisting in extending the 2D software to a 3D one, with the severity caused by modelling in three dimensions. This phase is developed as a common project and described in this thesis and in “Pre-process for numerical analysis of Cross Laminated Timber Structures” by Alessandra Ferrandino. The final aim of the software is to enable the modelling of an X-Lam structure in the most efficient and reliable way, taking into account its peculiarities. Modelling of CLT buildings lies into properly model the connections between panels. Through the connections modelling, the final aim is to enable the check of preliminarily designed connections or to find them iteratively, starting from hypothetical or random connections. This common project develops the pre-process and analysis phases of the 3D software that allows the automatic modelling of connections between X-Lam panels. To achieve the goal, a new problem type for GiD interface and a new application for KRATOS framework have been performed. The problem type enables the user to model a CLT structure, starting from the creation of the geometry and the assignation of numeric entities (beam, shell, etc.) to geometric ones, having defined the material, and assigning loads and boundary conditions. The user does not need to create manually the connections, as conversely needs for all commercial FEM software currently available; he just set the connection properties to the different sides of the panels. The creation of the connections is made automatically, keeping into account different typologies of connections and assembling of Cross-Lam panels. The problem type is special for XLam structures, meaning that all features are intentionally studied for this kind of structures and the software architecture is planned for future developments of the postprocess phase. It can be concluded that sound bases for the pre-process and analysis phases of the software have been laid. However, future research is required to develop the postprocess and verification phases of the research project.
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Analysis of Military Protective Structures: A Framework for Quantifying Cost-Benefit of Existing and New Protective Systems

https://research.thinkwood.com/en/permalink/catalogue1432
Year of Publication
2018
Topic
Design and Systems
Cost
Material
CLT (Cross-Laminated Timber)
Author
Crofoot, Henry
Organization
Colorado School of Mines
Year of Publication
2018
Country of Publication
United States
Format
Thesis
Material
CLT (Cross-Laminated Timber)
Topic
Design and Systems
Cost
Keywords
Protection
Military
Language
English
Research Status
Complete
Summary
The United States military is constantly evolving into an organization equipped by the latest technology and seeking the greatest protection per cost ratio for its members in harm’s way. While new protection methods are steadily produced by the Engineering Research and Development Command, most protective structure options fall into either very expensive or very labor-intensive structures with widely varying degrees of reusability and transportability. Furthermore, there is currently no widely accepted quantitative approach to help the decision-making process when choosing which system to use in a specific condition. This study will seek to create a framework which can be used to aid the decision-making process based on quantitative calculation of cost benefit of various protective systems. The framework will encompass resource metrics of man-hours, machine hours, and monetary cost. The calculations and assessments will also be affected by quantitative evaluations of military situations which can increase or decrease each value of resource metric. This study will also investigate the potential of using a mass timber product, namely Cross Laminated Timber (CLT) panels, as a protective structure that may be useful in certain military situations. While not designed to replace other systems, it is another option for military commanders and staffs to consider when choosing the most efficient and economical protection method for their soldiers.
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Analysis of the Timber-Concrete Composite Systems with Ductile Connection

https://research.thinkwood.com/en/permalink/catalogue113
Year of Publication
2013
Topic
Mechanical Properties
Material
Timber-Concrete Composite
Author
Zhang, Chao
Organization
University of Toronto
Year of Publication
2013
Country of Publication
Canada
Format
Thesis
Material
Timber-Concrete Composite
Topic
Mechanical Properties
Keywords
Bending
Ductility
Model
Load Deflection
Tension
Shear Connection
Language
English
Research Status
Complete
Summary
In timber-concrete composite systems, timber and concrete are inherently brittle materials that behave linearly elastic in both tension and bending. However, the shear connection between the members can exhibit significant ductility. It is therefore possible to develop timber-concrete composite systems with ductile connection that behave in a ductile fashion. This study illustrates the use of an elastic-perfectly plastic analytical approach to this problem. In addition, the study proposes an incremental method for predicting the nonlinear load-deflection response of the composite system. The accuracy of the analytical model is confirmed with a computer model, and numerical solutions of the analytical model are compared to experimental results from the bending tests conducted by previous researchers. Reasonable agreement is found from the comparisons, which validates the capacity of the analytical model in predicting the structural behaviour of the timber-concrete composite systems in both elastic and post-elastic stages.
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Free
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An Exploration into Tornado Resistant Residential CLT Structures

https://research.thinkwood.com/en/permalink/catalogue2111
Year of Publication
2019
Topic
Wind
Design and Systems
Mechanical Properties
Material
CLT (Cross-Laminated Timber)
Glulam (Glue-Laminated Timber)
Application
Wood Building Systems

Application of Ductile Yield Link in Glulam Moment Connections

https://research.thinkwood.com/en/permalink/catalogue2313
Year of Publication
2018
Topic
Connections
Design and Systems
Material
Glulam (Glue-Laminated Timber)
Application
Columns
Beams
Author
Almousawi, Sayed Husain
Publisher
Virginia Tech
Year of Publication
2018
Country of Publication
United States
Format
Thesis
Material
Glulam (Glue-Laminated Timber)
Application
Columns
Beams
Topic
Connections
Design and Systems
Keywords
Beam Column Connection
Moment Frame Connection
Self-Tapping Screws
Reinforcement
Language
English
Research Status
Complete
Online Access
Free
Resource Link
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Assessing the Fire Integrity Performance of Cross-Laminated Timber Floor Panel-To-Panel Joints

https://research.thinkwood.com/en/permalink/catalogue185
Year of Publication
2016
Topic
Connections
Fire
Material
CLT (Cross-Laminated Timber)
Application
Floors
Author
Dagenais, Christian
Organization
Carleton University
Year of Publication
2016
Country of Publication
Canada
Format
Thesis
Material
CLT (Cross-Laminated Timber)
Application
Floors
Topic
Connections
Fire
Keywords
Finite Element Model
Thickness
Codes
Panel-to-Panel
Joints
Canada
US
Fire Resistance
Language
English
Research Status
Complete
Summary
During the past few years, a relatively new technology has emerged in North America and changed the way professionals design and build wood structures: Cross-laminated Timber (CLT). CLT panels are manufactured in width ranging from 600 mm to 3 m. As such, fastening them together along their major strength axis is required in order to form a singular structural assembly resisting to in-plane and out-of-plane loading. Typical panel-to-panel joint details of CLT assemblies may consist of internal spline(s), single or double surface splines or half-lapped joints. These tightly fitted joint profiles should provide sufficient fire-resistance, but have yet to be properly evaluated for fire-resistance in CLT assemblies. The experimental portion of the study consisted at conducting ten (10) intermediate-scale fire-resistance tests of CLT floor assemblies with four (4) types of panel-to-panel joints and three (3) CLT thicknesses. The data generated from the intermediate-scale fire tests were used to validate a finite element heat transfer model, a coupled thermal-structural model and a simplified design model. The latter is an easy-to-use design procedure for evaluating the fire integrity resistance of the four commonly-used CLT floor assemblies and could potentially be implemented into building codes and design standards. Based on the test data and models developed in this study, joint coefficient values were derived for the four (4) types of CLT panel-to-panel joint details. Joint coefficients are required when assessing the fire integrity of joints using simple design models, such as the one presented herein and inspired from Eurocode 5: Part 1-2. The contribution of this study is to increase the knowledge of CLT exposed to fire and to facilitate its use in Canada and US by complementing current fire-resistance design methodologies of CLT assemblies, namely with respect to the fire integrity criterion. Being used as floor and wall assemblies, designers should be capable to accurately verify both the load-bearing and separating functions of CLT assemblies in accordance with fire-related provisions of the building codes, which are now feasible based on the findings of this study.
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Assessment and Optimisation of CFRP Reinforced Glulam Beams - A Feasibility Study in Design Stage Reinforcement Configurations for Pedestrian Bridge Applications

https://research.thinkwood.com/en/permalink/catalogue2458
Year of Publication
2019
Topic
Mechanical Properties
Material
Glulam (Glue-Laminated Timber)
Application
Bridges and Spans

212 records – page 1 of 22.