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30 records – page 1 of 3.

Analytical Modeling of Lateral Strength and Stiffness of Inclined Self-Tapping Screw Connection

https://research.thinkwood.com/en/permalink/catalogue2651
Topic
Mechanical Properties
Connections
Author
Zhao, Ruihan
Organization
University of Alberta
Topic
Mechanical Properties
Connections
Keywords
Self-Tapping Screws
Lateral Strength
Lateral Stiffness
Withdrawal
Yield
Embedment
Research Status
In Progress
Summary
The objective of this research is to develop models for predicting lateral strength and stiffness of connections containing inclined self-tapping screws, by considering the contribution of the withdrawal and yield properties of the screws and embedment properties of the connecting members.
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Analytical Procedure for Timber-Concrete Composite (TCC) System with Mechanical Connectors

https://research.thinkwood.com/en/permalink/catalogue3119
Year of Publication
2022
Topic
Design and Systems
Material
Timber-Concrete Composite
Application
Floors
Author
Mirdad, Md Abdul Hamid
Khan, Rafid
Chui, Ying Hei
Organization
University of Illinois at Urbana-Champaign
University of Alberta
Editor
Tullini, Nerio
Publisher
MDPI
Year of Publication
2022
Format
Journal Article
Material
Timber-Concrete Composite
Application
Floors
Topic
Design and Systems
Keywords
Mechanical Connectors
Progressive Yielding
Effective Bending Stiffness
Deflection
Vibration
Research Status
Complete
Series
Buildings
Summary
In the construction of modern multi-storey mass timber structures, a composite floor system commonly specified by structural engineers is the timber–concrete composite (TCC) system, where a mass timber beam or mass timber panel (MTP) is connected to a concrete slab with mechanical connectors. The design of TCC floor systems has not been addressed in timber design standards due to a lack of suitable analytical models for predicting the serviceability and safety performance of these systems. Moreover, the interlayer connection properties have a large influence on the structural performance of a TCC system. These connection properties are often generated by testing. In this paper, an analytical approach for designing a TCC floor system is proposed that incorporates connection models to predict connection properties from basic connection component properties such as embedment and withdrawal strength/stiffness of the connector, thereby circumventing the need to perform connection tests. The analytical approach leads to the calculation of effective bending stiffness, forces in the connectors, and extreme stresses in concrete and timber of the TCC system, and can be used in design to evaluate allowable floor spans under specific design loads and criteria. An extensive parametric analysis was also conducted following the analytical procedure to investigate the TCC connection and system behaviour. It was observed that the screw spacing and timber thickness remain the most important parameters which significantly influence the TCC system behaviour.
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Comparison of Theoretical and Laboratory Out-of-Plane Shear Stiffness Values of Cross Laminated Timber Panels

https://research.thinkwood.com/en/permalink/catalogue2177
Year of Publication
2018
Topic
Mechanical Properties
Material
CLT (Cross-Laminated Timber)
Author
Niederwestberg, Jan
Zhou, Jianhui
Chui, Ying-hei
Organization
University of Alberta
University of Northern British Columbia
Publisher
MDPI
Year of Publication
2018
Format
Journal Article
Material
CLT (Cross-Laminated Timber)
Topic
Mechanical Properties
Keywords
Shear Behaviour
Out Of Plane
Shear Stiffness
Timoshenko Theory of Bending
Shear Modulus
Research Status
Complete
Series
Buildings
Summary
The lay-up of cross laminated timber (CLT) leads to significant differences in properties over its cross-section. Particularly the out-of-plane shear behavior of CLT is affected by the changes in shear moduli over the cross-section. Results from laboratory shear tests are used to evaluate the shear stiffness of 3- and 5-layer CLT panels in their major and minor strength direction. The results are compared to calculated shear stiffness values on evaluated single-layer properties as well as commonly used property ratios using the Timoshenko beam theory and the shear analogy method. Differences between the two calculation approaches are pointed out. The shear stiffness is highly sensitive to the ratio of the shear modulus parallel to the grain to the shear modulus perpendicular to the grain. The stiffness values determined from two test measurements are compared with the calculated results. The level of agreement is dependent on the number of layers in CLT and the property axis of the CLT panels.
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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 and Experimental Analysis of Connections for a Panelized Wood Frame Roof System

https://research.thinkwood.com/en/permalink/catalogue3206
Year of Publication
2022
Topic
Mechanical Properties
Material
LSL (Laminated Strand Lumber)
Application
Roofs
Author
Islam, Md Saiful
Chui, Ying Hei
Altaf, Mohammed Sadiq
Organization
University of Alberta
ACQBUILT Inc.
Editor
Nocera, Francesco
Publisher
MDPI
Year of Publication
2022
Format
Journal Article
Material
LSL (Laminated Strand Lumber)
Application
Roofs
Topic
Mechanical Properties
Keywords
Panelized Roof
Home Manufacturing
Wall Framing Stations
Self-tapping screw
Research Status
Complete
Series
Buildings
Summary
This paper presents the results of an experimental study on the short-term mechanical performance of timber screw connections comprising two types of fasteners suitable for a novel panelized roof design process. Thirty-seven specimens of five different connection configurations were tested under quasi-static monotonic loading. The main objective of this study is to provide a preliminary assessment of connection capacity that is key to the successful implementation of a proposed panelized roof design method. It also provides the basis to assist in the development of a numerical model of the novel roof assembly. Additionally, the experimental data are used to check the validity of existing analytical approaches for predicting the strengths of screwed connections comprising engineered wood members. The validation exercise shows that available analytical models can be used to predict the connection capacity of the novel panelized roof.
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Free
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Design and simulation of an automated robotic machining cell for cross-laminated timber panels

https://research.thinkwood.com/en/permalink/catalogue2966
Year of Publication
2021
Topic
Market and Adoption
Material
CLT (Cross-Laminated Timber)
Author
Villanueva, Emanuel Martinez
Mamledesai, Harshavardhan
Martinez, Pablo
Poostchi, Peyman
Ahmad, Rafiq
Organization
University of Alberta
University of Calgary
Publisher
Elsevier
Year of Publication
2021
Format
Conference Paper
Material
CLT (Cross-Laminated Timber)
Topic
Market and Adoption
Keywords
Automation in Construction
Industrial Design
Offsite Construction
Robotic Simulation
Conference
31st CIRP Design Conference 2021
Research Status
Complete
Series
Procedia CIRP
Summary
Cross-laminated timber (CLT) is an innovative construction material that has brought advantages over traditional wood structures, reducing cost and lead time of buildings in recent years; yet CLT benefits primarily from offsite construction methods instead of automation or safety, while keeping the human onsite. The few advancements in automation for CLT panels have been in the implementation of dedicated CNC machines. Nevertheless, using CNC machines for machining CLT panels have disadvantages like clamping batches of massive panels with individual profiles, lacking the flexibility to access all acute machining angles, and struggling with the extraction of dust while the cutting spindle moves through large tight spaces. These disadvantages can be overcome with industrial robots’ help, which the construction industry has not been traditionally favorable on their application, giving then the research gap in this study. This paper explores the introduction of a robotic cell for the machining of cross-laminated timber panels. The robotic cell is designed using 3D modeling and validated through motion simulation in a virtual environment. The proposed cell design is based on a minimum viable product and compared against a minimum throughput benchmarked on the Canadian market. This study aims to research the feasibility of CLT’s automated machining by providing clear production characteristics of the designed robotic cell, such as material and tool utilization rates, lead time, or production efficiency.
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Free
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Development of Innovative MTP-Concrete Composite Floor System with Notched Timber Connection

https://research.thinkwood.com/en/permalink/catalogue2659
Topic
Connections
Design and Systems
Mechanical Properties
Material
Timber-Concrete Composite
Application
Floors
Author
Zhang, Lei
Organization
University of Alberta
Material
Timber-Concrete Composite
Application
Floors
Topic
Connections
Design and Systems
Mechanical Properties
Keywords
Stiffness
Strength
Notched Connections
Shrinkage
Research Status
In Progress
Summary
The objective of this research is to develop optimum notch profile to achieve maximum connection stiffness and strength properties, characterize notched timber connection MTP-concrete floor systems, including concrete shrinkage and develop floor system details and design procedure.
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Development of Mass Timber Panel-Concrete Composite Floor Span Table

https://research.thinkwood.com/en/permalink/catalogue2660
Topic
Design and Systems
Connections
Material
Timber-Concrete Composite
Application
Floors
Author
Li, Jialin
Organization
University of Alberta
Material
Timber-Concrete Composite
Application
Floors
Topic
Design and Systems
Connections
Keywords
Span Table
Research Status
In Progress
Summary
An increasingly popular composite floor system consists of a Mass Timber Panel (MTP) connected to a concrete slab or topping with mechanical connectors such as Self-Tapping Screws (STS) and a sound insulation layer in between. The concrete topping provides not only structural functions, but also help to enhance acoustic and fire performances. To facilitate the design of these floor systems that meet the criteria of strength, deflection, vibration, acoustics, and fire, pre-determined allowable spans in the format of a table will be beneficial. This report presents the procedure to develop a span table showing allowable spans for specific combinations of timber panel size and grade, concrete thickness, and connection properties.
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Development of Rigging System for Prefabricated Engineered Wood Floor Panels

https://research.thinkwood.com/en/permalink/catalogue2244
Topic
Connections
Site Construction Management
Application
Floors
Organization
University of Alberta
Application
Floors
Topic
Connections
Site Construction Management
Keywords
Prefabrication
Rigging System
Research Status
In Progress
Notes
Project contact is Y.H. Chui at the University of Alberta
Summary
The objective of this research is to develop efficient panel-to-panel connection details, and optimum floor configuration, including rigging details, for handling in the factory and at the construction site. Computer modelling will be conducted to develop preliminary recommendations on panel-to-panel connection details and optimum floor panel configuration. These recommendations will then be validated by a testing program in the laboratory.
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Development of Rotational Fixity Factors for Vibration Design of Cross-Laminated Timber Floors

https://research.thinkwood.com/en/permalink/catalogue2843
Year of Publication
2018
Topic
Acoustics and Vibration
Serviceability
Material
CLT (Cross-Laminated Timber)
Application
Floors
Author
Zhang, Sigong
Zhou, Jianhui
Niederwestberg, Jan
Chui, Ying Hei
Organization
University of Alberta
University of Northern British Columbia
Publisher
Preprints
Year of Publication
2018
Material
CLT (Cross-Laminated Timber)
Application
Floors
Topic
Acoustics and Vibration
Serviceability
Keywords
End Support
Vibration Serviceability
Floor-Wall Connection
Research Status
Complete
Summary
As an emerging building solution, cross-laminated timber (CLT) floors have been increasingly used in mass timber construction. The current vibration design of CLT floors is conservative due to the assumption of simple support conditions in the floor-to-wall connections. It is noted that end fixity occurs as a result of clamping action at the ends, arising from the gravity load applied by the structure above the floor and by the mechanical fasteners. In this paper, the semi-rigid floor-to-wall connections are treated as elastically restrained edges against rotations to account for the effect of partial constraint. A rotational end-fixity factor was first defined to reflect the relative bending stiffness between CLT floors and elastic restraints at the edges. Then, for the design of vibration serviceability of CLT floors as per the Canadian Standard for Engineering Design in Wood (CSA O86), restraint coefficients were defined and their analytical expressions were derived for natural frequencies and the mid-span deflection under a concentrated load, respectively. In particular, a simplified formula of the restraint coefficient for the fundamental frequency was developed to assist engineers in practical design. At last, by comparing with reported experimental data, the proposed design formula showed excellent agreement with test results. In the end, the proposed end fixity factor with their corresponding restraint coefficients is recommended as an effective mechanics-based approach to account for the effect of end support conditions of CLT floors.
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30 records – page 1 of 3.