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35 records – page 1 of 4.

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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Bamboo/Wood Composites and Structures Shear and Normal Strain Distributions in Multilayer Composite Laminated Panels under Out-of-Plane Bending

https://research.thinkwood.com/en/permalink/catalogue2769
Year of Publication
2021
Topic
Mechanical Properties
Material
CLT (Cross-Laminated Timber)
Author
Niederwestberg, Jan
Zhou, Jianhui
Chui, Ying Hei
Huang, Dongsheng
Publisher
Hindawi Publishing Corporation
Year of Publication
2021
Format
Journal Article
Material
CLT (Cross-Laminated Timber)
Topic
Mechanical Properties
Keywords
Three Point Bending Test
Shear Test
Digital Image Correlation
Strain
Shear Analogy
Finite Element Modelling
Stress
Research Status
Complete
Series
Advances in Civil Engineering
Summary
Innovative mass timber panels, known as composite laminated panels (CLP), have been developed using lumber and laminated strand lumber (LSL) laminates. In this study, strain distributions of various 5-layer CLP and cross-laminated timber (CLT) were investigated by experimental and two modelling methods. Seven (7) different panel types were tested in third-point bending and short-span shear tests. During the tests, the digital imaging correlation (DIC) technique was used to measure the normal and shear strain in areas of interest. Evaluated component properties were used to determine strain distributions based on the shear analogy method and finite element (FE) modelling. The calculated theoretical strain distributions were compared with the DIC test results to evaluate the validity of strain distributions predicted by the analytical model (shear analogy) and numerical model (FE analysis). In addition, the influence of the test setup on the shear strain distribution was investigated. Results showed that the DIC strain distributions agreed well with the ones calculated by the shear analogy method and FE analysis. Both theoretical methods agree well with the test results in terms of strain distribution shape and magnitude. While the shear analogy method shows limitations when it comes to local strain close to the supports or gaps, the FE analysis reflects these strain shifts well. The findings support that the shear analogy is generally applicable for the stress and strain determination of CLP and CLT for structural design, while an FE analysis can be beneficial when it comes to the evaluation of localized stresses and strains. Due to the influence of compression at a support, the shear strain distribution near the support location is not symmetric. This is confirmed by the FE method.
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Behaviour of Mass Timber Panel-Concrete Connections with Inclined Self-Tapping Screws and Insulation Layer

https://research.thinkwood.com/en/permalink/catalogue1984
Year of Publication
2018
Topic
Mechanical Properties
Connections
Material
Timber-Concrete Composite
CLT (Cross-Laminated Timber)
Application
Floors
Author
Abdul Hamid Mirdad, Md
Chui, Ying Hei
Year of Publication
2018
Format
Conference Paper
Material
Timber-Concrete Composite
CLT (Cross-Laminated Timber)
Application
Floors
Topic
Mechanical Properties
Connections
Keywords
Self-Tapping Screws
Insulation
Mid-Rise
High-Rise
Stiffness
Strength
Conference
World Conference on Timber Engineering
Research Status
Complete
Summary
The Mass Timber Panel-Concrete (MTPC) composite floor system considered in this paper consists of a Mass Timber Panel (MTP) connected to reinforced concrete slab with Self-Tapping Screw (STS) connector and a sound insulation layer in between. This type of composite floor system is intended for mid- to high-rise building applications. Two types of MTPs with normal weight concrete, two insulation thicknesses, two screw embedment lengths and two screw angles were investigated through connection tests to characterize connection stiffness and strength. The main goal of this connection test program was to provide preliminary test data to assist in the development of a model to predict connections lateral stiffness and strength under consideration of insulation thickness, screw angle, withdrawal and embedment properties of screws in MTP. Connection test results show that screws at an insertion angle of 30° have a higher stiffness and strength along with a larger embedment length compared to the screws at a 45° angle and smaller embedment length. Stiffness seemed to be more susceptible to the influence of presence of insulation compared to strength with 40-65% reduction of stiffness and 10-20% reduction of strength were noticed for an insulation thickness of 5 mm. Screws in CLT showed higher strength while screws in CLP showed higher stiffness but the difference is insignificant.
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Bending Properties of Innovative Multi-Layer Composite Laminated Panels

https://research.thinkwood.com/en/permalink/catalogue1985
Year of Publication
2018
Topic
Mechanical Properties
Material
LSL (Laminated Strand Lumber)
OSL (Oriented Strand Lumber)
Application
Beams
Author
Zhou, Jianhui
Niederwestberg, Jan
Chui, Ying Hei
Gong, Meng
Year of Publication
2018
Format
Conference Paper
Material
LSL (Laminated Strand Lumber)
OSL (Oriented Strand Lumber)
Application
Beams
Topic
Mechanical Properties
Keywords
Bending Stiffness
Shear Stiffness
Moment Capacity
Failure Modes
Three Point Bending Test
Modal Test
Conference
World Conference on Timber Engineering
Research Status
Complete
Summary
An innovative multi-layer (3 and 5) composite laminated panel (CLP) with various layups were developed using sawn lumber and structural composite lumber (SCL) to address the rolling shear and gap issues of cross laminated timber (CLT). The bending properties including apparent and effective bending stiffness, shear stiffness, moment capacities and failure modes of CLPs were evaluated by a combination of modal tests and third-point bending tests of beam specimens cut from the panels. The static bending test results showed that the apparent bending stiffness values of 3-layer and 5-layer CLPs were up to 20% and 43% higher than the corresponding values of 3-layer and 5-layer generic CLT, respectively. The bending moment capacity values of 3-layer and 5-layer CLPs were up to 37% and 87% higher than the corresponding values of 3-layer and 5-layer generic CLT, respectively. The use of SCL in transverse layers eliminated the potential rolling shear failure in CLT and increased the stiffness properties. The apparent and effective bending stiffness predicted by shear analogy method had a good agreement with corresponding values measured by bending tests and/or modal tests. The prediction of bending moment capacity using shear analogy method cannot be validated due to the rolling shear failure and tension failure modes observed in certain groups.
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Characterizing Influence of Laminate Characteristics on Elastic Properties of Cross Laminated Timber

https://research.thinkwood.com/en/permalink/catalogue221
Year of Publication
2014
Topic
Mechanical Properties
Material
CLT (Cross-Laminated Timber)
Author
Niederwestberg, Jan
Chui, Ying Hei
Year of Publication
2014
Format
Conference Paper
Material
CLT (Cross-Laminated Timber)
Topic
Mechanical Properties
Keywords
Modal Testing
Laminates
Conference
World Conference on Timber Engineering
Research Status
Complete
Notes
August 10-14, 2014, Quebec City, Canada
Summary
Properties of CLT panels are influenced by the properties of their layers and the layer properties are in turn influenced by the structural characteristics of the laminate material. In order to realize the mechanical property potential of CLT panels it is necessary to understand the effects of laminate properties on the performance of the final product. This paper presents the approach and outcomes of an on-going study dealing with the evaluation of material and structural characteristics of laminates and their effects on overall characteristics of CLT using modal testing. Characteristics of “homogenised” layers and CLT panels were evaluated using modal and static testing. The suitability of test methods was established for single-layer panels and CLT panels. Relationships between overall single-layer properties and laminate characteristics were established. Differences in CLT properties calculated by different calculation models were discussed.
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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)

Cross-Laminated Timber Shear Walls in Balloon Construction: Seismic Performance of Steel Connections

https://research.thinkwood.com/en/permalink/catalogue2413
Year of Publication
2019
Topic
Seismic
Connections
Material
CLT (Cross-Laminated Timber)
Application
Walls

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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Design Method for Controlling Vibrations of Wood-Concrete Composite Floors Systems

https://research.thinkwood.com/en/permalink/catalogue1689
Year of Publication
2016
Topic
Acoustics and Vibration
Design and Systems
Mechanical Properties
Material
Timber-Concrete Composite
Application
Floors
Author
Hu, Lin
Cuerrier-Auclair, Samuel
Chui, Ying Hei
Ramzi, Redouane
Gagnon, Sylvain
Mohammad, Mohammad
Ni, Chun
Popovski, Marjan
Year of Publication
2016
Format
Conference Paper
Material
Timber-Concrete Composite
Application
Floors
Topic
Acoustics and Vibration
Design and Systems
Mechanical Properties
Keywords
Natural Frequencies
Deflection
Bending Stiffness
Conference
World Conference on Timber Engineering
Research Status
Complete
Notes
August 22-25, 2016, Vienna, Austria p. 4237-4245
Summary
Wood-concrete composite slab floors provide a promising solution for achieving long spans and shallow wood-based floor systems for large and tall wood buildings. In comparison with conventional wood floor systems, such long span and heavy floors have a lower fundamental natural frequency, which challenges the floor vibration controlled design. A laboratory study, including subjective evaluation and measurement of the natural frequencies and one-kN static deflections, was conducted on wood-concrete composite floors. Method of calculation of the composite bending stiffness of the wood-concrete composite floor is proposed. The design criterion for human comfort was derived from the subjective evaluation results using the calculated fundamental natural frequency and 1 kN static deflection of one meter wide strip of the composite floor. The equation to directly determine the vibration controlled spans from the stiffness and mass was derived. Limited verification was performed. Further verification is needed when more field wood-concrete composite floors become available.
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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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35 records – page 1 of 4.