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Predicting the Human-Induced Vibration of Cross Laminated Timber Floor Under Multi-Person Loadings

https://research.thinkwood.com/en/permalink/catalogue2701
Year of Publication
2021
Topic
Acoustics and Vibration
Material
CLT (Cross-Laminated Timber)
Application
Floors
Author
Wang, Chang
Chang, Wen-Shao
Yan, Weiming
Huang, Haoyu
Publisher
ScienceDirect
Year of Publication
2021
Format
Journal Article
Material
CLT (Cross-Laminated Timber)
Application
Floors
Topic
Acoustics and Vibration
Keywords
Human-Induced Vibration
Multi-Person Loadings
Numerical Modelling
Language
English
Research Status
Complete
Series
Structures
Summary
The vibration of cross laminated timber (CLT) floor is closely related to human-induced loadings. However, research and prediction approaches regarding human-induced vibration of the CLT floor have been mostly limited to a single-person excitation condition. This paper presents new prediction approaches to the vibration response of the CLT floor under multi-person loadings. The effect of multi-person loadings on the vibration performance of a CLT floor was investigated through numerical modelling, experimental testing and analytical investigation. A finite element model was developed through a computational software to perform an accurate analysis of human-induced loadings. An analytical model was established to predict human-induced vibration of the CLT floor under multi-person loadings. Experimental tests were conducted to validate the numerical modelling. Results of both numerical modelling and experimental testing showed that the vibration performance of the CLT floor under multi-person loadings was almost double that under single-person loadings. Thus, multi-person activities are more likely to cause the occupants feelings of discomfort. A method for predicting the human-induced vibration of the CLT floor under multi-person loadings was then developed. The measured response, numerical modelled response, and predicted response were compared using an existing design metric, vibration dose value (VDV). The results were largely consistent. It is therefore concluded that the proposed prediction method will enable engineers to design timber floor systems that consider multi-person loadings.
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Cyclic Response of Insulated Steel Angle Brackets Used for Cross-Laminated Timber Connections

https://research.thinkwood.com/en/permalink/catalogue2765
Year of Publication
2021
Topic
Seismic
Acoustics and Vibration
Connections
Material
CLT (Cross-Laminated Timber)
Application
Walls
Floors
Author
Kržan, Meta
Azinovic, Boris
Publisher
Springer
Year of Publication
2021
Format
Journal Article
Material
CLT (Cross-Laminated Timber)
Application
Walls
Floors
Topic
Seismic
Acoustics and Vibration
Connections
Keywords
Angle Bracket
Sound Insulation
Insulation
Monotonic Test
Cyclic Tests
Wall-to-Floor
Stiffness
Load Bearing Capacity
Shear
Tensile
Language
English
Research Status
Complete
Series
European Journal of Wood and Wood Products
Summary
In cross-laminated timber (CLT) buildings, in order to reduce the disturbing transmission of sound over the flanking parts, special insulation layers are used between the CLT walls and slabs, together with insulated angle-bracket connections. However, the influence of such CLT connections and insulation layers on the seismic resistance of CLT structures has not yet been studied. In this paper, experimental investigation on CLT panels installed on insulation bedding and fastened to the CLT floor using an innovative, insulated, steel angle bracket, are presented. The novelty of the investigated angle-bracket connection is, in addition to the sound insulation, its resistance to both shear as well as uplift forces as it is intended to be used instead of traditional angle brackets and hold-down connections to simplify the construction. Therefore, monotonic and cyclic tests on the CLT wall-to-floor connections were performed in shear and tensile/compressive load direction. Specimens with and without insulation under the angle bracket and between the CLT panels were studied and compared. Tests of insulated specimens have proved that the insulation has a marginal influence on the load-bearing capacity; however, it significantly influences the stiffness characteristics. In general, the experiments have shown that the connection could also be used for seismic resistant CLT structures, although some minor improvements should be made.
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Predicting Fire Resistance Ratings of Timber Structures Using Artificial Neural Networks

https://research.thinkwood.com/en/permalink/catalogue2383
Year of Publication
2020
Topic
Fire
Application
Wood Building Systems
Floors
Author
Tung, Pham Thanh
Hung, Pham Thanh
Publisher
National University of Civil Engineering
Year of Publication
2020
Country of Publication
Vietnam
Format
Journal Article
Application
Wood Building Systems
Floors
Topic
Fire
Keywords
Artificial Neural Network
Fire Resistance
Sensitivity Analysis
Wooden Floor Assembly
Language
English
Research Status
Complete
Series
Journal of Science and Technology in Civil Engineering
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Encapsulated Mass Timber Construction Char Rate Analysis

https://research.thinkwood.com/en/permalink/catalogue2387
Year of Publication
2020
Topic
Fire
Material
CLT (Cross-Laminated Timber)
Application
Floors
Walls

Mechanical Experimental Study on Tensile Bolted Connections of Crosslaminated Timber

https://research.thinkwood.com/en/permalink/catalogue2450
Year of Publication
2020
Topic
Connections
Mechanical Properties
Material
CLT (Cross-Laminated Timber)
Application
Walls
Floors
Author
Su, Chenxiao
Xiong, Haibei
Publisher
Tech Science Press
Year of Publication
2020
Country of Publication
United States
Format
Journal Article
Material
CLT (Cross-Laminated Timber)
Application
Walls
Floors
Topic
Connections
Mechanical Properties
Keywords
Monotonic Loading
Cyclic Loading
Deformation
Failure Modes
Wall-to-Wall
Wall-to-Floor
Bolted Connection
Load-Slip
Bearing Capacity
Yielding Point
Stiffness
Ductility
Language
English
Research Status
Complete
Series
Structural Durability & Health Monitoring
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Free
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Design Guide for Timber-Concrete Composite Floors in Canada

https://research.thinkwood.com/en/permalink/catalogue2460
Year of Publication
2020
Topic
Design and Systems
Connections
Acoustics and Vibration
Fire
Material
Timber-Concrete Composite
Application
Floors
Organization
FPInnovations
Year of Publication
2020
Country of Publication
Canada
Format
Book/Guide
Material
Timber-Concrete Composite
Application
Floors
Topic
Design and Systems
Connections
Acoustics and Vibration
Fire
Keywords
Shear Connection
Ultimate Limit States
Vibration
Fire Resistance
Language
English
Research Status
Complete
Summary
As part of its research work on wood buildings, FPInnovations has recently launched a Design Guide for Timber-Concrete Composite Floors in Canada. This technique, far from being new, could prove to be a cost-competitive solution for floors with longer-span since the mechanical properties of the two materials act in complementarity. Timber-concrete systems consist of two distinct layers, a timber layer and a concrete layer (on top), joined together by shear connectors. The properties of both materials are then better exploited since tension forces from bending are mainly resisted by the timber, while compression forces from bending are resisted by the concrete. This guide, which contains numerous illustrations and formulas to help users better plan their projects, addresses many aspects of the design of timber-concrete composite floors, for example shear connection systems, ultimate limit state design, vibration and fire resistance of floors, and much more.
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Calculating the Fire Resistance of Wood Members and Assemblies: Technical Report No. 10

https://research.thinkwood.com/en/permalink/catalogue2492
Year of Publication
2020
Topic
Fire
Design and Systems
Material
CLT (Cross-Laminated Timber)
Application
Columns
Beams
Floors
Walls
Wood Building Systems
Decking

Encapsulation of Mass Timber Floor Surfaces

https://research.thinkwood.com/en/permalink/catalogue2528
Year of Publication
2020
Topic
Design and Systems
Fire
Material
NLT (Nail-Laminated Timber)
Glulam (Glue-Laminated Timber)
CLT (Cross-Laminated Timber)
Application
Floors

Flame Spread in Concealed Mass Timber Spaces

https://research.thinkwood.com/en/permalink/catalogue2529
Year of Publication
2020
Topic
Fire
Application
Walls
Floors
Author
Ranger, Lindsay
Dagenais, Christian
Organization
FPInnovations
Year of Publication
2020
Country of Publication
Canada
Format
Report
Application
Walls
Floors
Topic
Fire
Keywords
Floor Voids
Fire Tests
Mid-Rise
Concealed Spaces
Fire Performance
Mass Timber
Language
English
Research Status
Complete
Summary
The overall objective of this work is to expand options for designers of mass timber buildings by reducing the dependence on concrete and gypsum board though the demonstration of adequate fire performance of mass timber assemblies. This work is intended to demonstrate that mass timber surfaces can be left exposed in concealed spaces, under certain conditions, while still performing well to control flame spread; this could result in significant savings in construction. Flame spread testing will be completed to compare the performance of mass timber assemblies and concealed space designs that are currently allowed by the NFPA 13 to be exempt from the installation ofsprinklers. Data is needed to support the use of exposed mass timber in concealed spaces by demonstrating limited flame spread in concealed mass timber void spaces. Flame spread testing has already shown that mass timber has lower flame spread ratings than typically found with thinner wood panels. This will lead the way in allowing unsprinklered 305 mm (12 in.) deep concealed spaces beneath mass timber assemblies or exposed mass timber in other concealed spaces such as hollow wood floor beams. The goal is to generate data to support the use of exposed mass timber in concealed spaces. This data could be used in an Alternative Solution to gain approval for this type of design. Ultimately, this could lead to changing the NBCC to allow exposed mass timber in concealed spaces.
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Influence of Layer Arrangement on Bonding and Bending Performances of Cross-laminated Timber Using Two Different Species

https://research.thinkwood.com/en/permalink/catalogue2591
Year of Publication
2020
Topic
Design and Systems
Mechanical Properties
Material
CLT (Cross-Laminated Timber)
Application
Walls
Floors
Author
Kim, Keon-Ho
Publisher
North Carolina State University
Year of Publication
2020
Format
Journal Article
Material
CLT (Cross-Laminated Timber)
Application
Walls
Floors
Topic
Design and Systems
Mechanical Properties
Keywords
Bonding Performance
Bending Performance
Shear Walls
Face Bonding Test
Three-Point Bending Test
Japanese Larch
Korean Red Pine
Language
English
Research Status
Complete
Series
BioResources
Summary
Cross-laminated timber (CLT) is a wood panel product that can be arranged in different ways. The advantage of utilizing CLT is the ability to use lamination even with low density materials or those that have defects, like knots. This study evaluated the bonding and bending performances of CLT utilizing domestic species in a shear wall or floor via a face bonding test of layers and a three-point bending test. The tests were carried out with three-layered CLT made up of Japanese larch and/or Korean red pine in various configurations. The layer arrangement for lamination was divided according to the species and grade of the wood. The out-of-plane and in-plane bending tests were conducted on the CLT according to the applicable direction in a wooden structure. The results of the bonding test showed that the block shear strength and delamination of all types of CLT met the BS EN 16351 (2015) standard requirements. The results of the bending test based on two wood species showed that the bending strength of the larch CLT was higher than that of the pine CLT in single species combinations. For mixed species combinations, the bending properties of CLT using larch as the major layer was higher than those using pine as the major layer. This demonstrated that the major layer had more influence on the bending properties of CLT and that Korean red pine was more suited for the minor layer of CLT.
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Apparent Sound Insulation in Mass Timber Buildings

https://research.thinkwood.com/en/permalink/catalogue2616
Year of Publication
2020
Topic
Acoustics and Vibration
Design and Systems
Material
CLT (Cross-Laminated Timber)
NLT (Nail-Laminated Timber)
DLT (Dowel Laminated Timber)
Application
Floors
Walls
Author
Mahn, Jeffrey
Quirt, David
Mueller-Trapet, Markus
Hoeller, Christoph
Organization
National Research Council of Canada. Construction
Publisher
National Research Council of Canada. Construction
Year of Publication
2020
Country of Publication
Canada
Format
Report
Material
CLT (Cross-Laminated Timber)
NLT (Nail-Laminated Timber)
DLT (Dowel Laminated Timber)
Application
Floors
Walls
Topic
Acoustics and Vibration
Design and Systems
Keywords
Airborne Sound Transmission
Apparent Sound Transmission Class
Sound Transmission
Adhesive
Language
English
Research Status
Complete
Summary
This Report presents the results from experimental studies of the airborne sound transmission of mass timber assemblies, together with an explanation of the calculation procedures to predict the apparent sound transmission class (ASTC) rating between adjacent spaces in a building constructed of mass timber assemblies. The experimental data which is the foundation for this Report includes the laboratory measured sound transmission loss of wall and floor assemblies constructed of Cross Laminated Timber (CLT), Nail-Laminated Timber (NLT) and Dowel-Laminated Timber (DLT), and the laboratory measured vibration reduction index between assemblies of junctions between CLT assemblies. The presentation of the measured data is combined with the presentation of the appropriate calculation procedures to determine the ASTC rating in buildings comprised of such assemblies along with numerous worked examples. Several types of CLT constructions are commercially available in Canada, but this study focused on CLT assemblies with an adhesive applied between the faces of the timber elements in adjacent layers, but no adhesive bonding between the adjacent timber elements within a given layer. These CLT assemblies could be called “Face-Laminated CLT Assemblies” but are simply referred to as CLT assemblies in this Report. Another form of CLT assemblies does have adhesive applied between the faces of the timber elements in adjacent layers as well as adhesive to bond the adjacent timber elements within a given layer. These assemblies are referred to as “Fully-Bonded CLT Assemblies” in this Report. Because fully-bonded CLT assemblies have different properties than face-laminated CLT assemblies, the sound transmission data and predictions in this Report do not apply to fully-bonded CLT assemblies.
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Acoustically-Tested Mass Timber Assemblies

https://research.thinkwood.com/en/permalink/catalogue2639
Year of Publication
2020
Topic
Acoustics and Vibration
Material
CLT (Cross-Laminated Timber)
NLT (Nail-Laminated Timber)
Glulam (Glue-Laminated Timber)
MPP (Mass Plywood Panel)
Application
Floors
Walls

Performance of Notched Connectors for CLT-Concrete Composite Floors

https://research.thinkwood.com/en/permalink/catalogue2656
Year of Publication
2020
Topic
Mechanical Properties
Connections
Material
CLT (Cross-Laminated Timber)
Timber-Concrete Composite
Application
Floors
Author
Van Thai, Minh
Ménard, Sylvain
Elachachi, Sidi Mohammed
Galimard, Philippe
Publisher
MDPI
Year of Publication
2020
Format
Journal Article
Material
CLT (Cross-Laminated Timber)
Timber-Concrete Composite
Application
Floors
Topic
Mechanical Properties
Connections
Keywords
Notched Connections
Finite Element Model
Connectors
Deconstructable Connections
Screw
Language
English
Research Status
Complete
Series
Buildings
Summary
CLT-concrete composite floor systems are a solution for timber buildings with a long-span floor. It yields a reduction of carbon footprint and even eco-friendly structure at the end of its service life. This study will evaluate the structural performance of notched connectors in the CLT-concrete composite floor, comprised of the serviceability stiffness, maximum load, and behavior at failure. The parameters of the test plan are the loaded edge length, the notch depth, the concrete thickness, and the screw length. Other secondary variables are also assessed, such as different loading sequences, speed of test, and timber moisture content. Experimental results prove that the performance of the connector depends significantly but not linearly on the notch depth and the length of the loaded edge. The connector with a deeper notch and a shorter heel will be stiffer and more robust, but it also tends to have a brittle rupture. The test results also help validate a solution for deconstructable connector systems. A nonlinear finite element model of the connector is built and validated versus the experimental results. It yields reasonably good predictions in terms of resistance and can capture the load-slip relationship.
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Effect of Design Parameters on Mass Timber Floor Vibration Performance

https://research.thinkwood.com/en/permalink/catalogue2683
Year of Publication
2020
Topic
Acoustics and Vibration
Design and Systems
Material
DLT (Dowel Laminated Timber)
Application
Floors
Author
Hu, Lin
Organization
FPInnovations
Year of Publication
2020
Country of Publication
Canada
Format
Report
Material
DLT (Dowel Laminated Timber)
Application
Floors
Topic
Acoustics and Vibration
Design and Systems
Keywords
Concrete Topping
Plywood
Vibration Performance
Bending Stiffness
Language
English
Research Status
Complete
Summary
Mass timber is a generic name for a broad range of thick and heavy wood products such as cross-laminated timber (CLT), dowel-laminated timber (DLT), nail-laminated timber (NLT), and gluelaminated timber (GLT), among others. So far, vibration-controlled design methods have been developed mostly for CLT floors.
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Effet des Paramètres de Conception Sur la Performance Vibratoire des Planchers Massifs en Bois

https://research.thinkwood.com/en/permalink/catalogue2684
Year of Publication
2020
Topic
Acoustics and Vibration
Energy Performance
Material
DLT (Dowel Laminated Timber)
Application
Floors
Author
Hu, Lin
Organization
FPInnovations
Year of Publication
2020
Country of Publication
Canada
Format
Report
Material
DLT (Dowel Laminated Timber)
Application
Floors
Topic
Acoustics and Vibration
Energy Performance
Keywords
Concrete Topping
Plywood
Vibration Performance
Bending Stiffness
Language
French
Research Status
Complete
Summary
La construction massive en bois est un terme générique qui englobe une grande variété de produits du bois épais et lourds, notamment le bois lamellé-croisé (CLT), le bois lamellé-goujonné (DLT), le bois lamellé-cloué et le bois lamellé-collé (GLT). À ce jour, les méthodes de conception à vibrations contrôlées ont surtout été élaborées pour les planchers en CLT.
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Design and Performance of High-Rise Structure using Ultra-Lightweight Cross Laminated Timber Floor System

https://research.thinkwood.com/en/permalink/catalogue2698
Year of Publication
2020
Topic
Mechanical Properties
Serviceability
Material
CLT (Cross-Laminated Timber)
Application
Floors
Author
Ahmed, Danish
Ayadat, Tahar
Asiz, Andi
Publisher
ISEC Press
Year of Publication
2020
Format
Conference Paper
Material
CLT (Cross-Laminated Timber)
Application
Floors
Topic
Mechanical Properties
Serviceability
Keywords
Tall Timber Buildings
Lateral Load
Lateral Deflections
Floor Diaphragm
Language
English
Conference
International Structural Engineering and Construction Conference
Research Status
Complete
Series
Proceedings of International Structural Engineering and Construction
Summary
The main objective of this paper is to study the structural performance of a high-rise structure when alternative lightweight material known as cross-laminated timber was used as a slab in floor system in lieu of conventional reinforced concrete slab. A numerical case study was conducted using a highly irregular RC frame building with its two 60-story towers joined at the top. Three major analyses were considered. First, modeling and analyzing the building with an RC slab was conducted to determine the design reference. Second, substituting the RC slab with the CLT slab was performed using the same building skeleton. Third, redesigning and optimizing the building skeleton with that CLT to observe skeleton material saving obtained using the same structural performance criteria. Major lateral loads applicable in the Eastern Province of Saudi Arabia were inputted. Strengths and serviceability requirements for floor diaphragm and lateral load resisting system were checked first before performing a comparative analysis between traditional RC and CLT slabs as floor diaphragm. The structural performance criteria to be used for comparative study between RC and CLT slabs included total drift, inter-story drift due to lateral loads, and base reactions. Structural periods and acceleration responses for each floor were investigated and contrasted with the existing building code. The foundation demand was also investigated based on the structural weight and reactions generated from the RC and CLT floor systems.
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High Performance Connections to Mitigate Seismic Damage in Cross Laminated Timber (CLT) Structures

https://research.thinkwood.com/en/permalink/catalogue2707
Year of Publication
2020
Topic
Connections
Seismic
Material
CLT (Cross-Laminated Timber)
Application
Floors
Walls
Author
Smiroldo, Francesco
Gaspari, Andrea
Viel, Davide
Piazza, Maurizio
Year of Publication
2020
Format
Conference Paper
Material
CLT (Cross-Laminated Timber)
Application
Floors
Walls
Topic
Connections
Seismic
Keywords
Finite Element Modelling
Non-linear Analysis
Seismic Engineering
Earthquake
Connection Systems
Language
English
Conference
World Conference on Earthquake Engineering
Research Status
Complete
Summary
The present study proposes a new connection system for Cross Laminated Timber (CLT) structures in earthquake prone areas. The system is suitable for creating wall-floor-wall and wall-foundation connections, where each connection device can transfer both shear and tension forces, thus replacing the role of traditional “hold downs” and “angle brackets”, and eliminating possible uncertainty on the load paths and on the force-transfer mechanism. For design earthquakes intensity, the proposed system is designed to remain elastic without accessing the inelastic resources, avoiding in this way permanent deformations in both structural and non-structural elements. However, in case of unforeseen events of exceptional intensity, the system exhibits a pseudo-ductile behaviour, with significant deformation capacity. Furthermore, in the proposed system the vertical forces are directly transferred through the contact between wall panels, avoiding compressions orthogonal to the grain of the floor panels. In this research, the connection system was analysed via finite element modelling based on numerical strategies with different levels of refinements. Nonlinear analyses were performed in order to investigate the response of the connection to shear, tension and a combination of such forces. The numerical responses were compared with those of full-scale experimental tests performed on the proposed connection subjected to different kind of loading configuration. The results appear as promising, suggesting that the proposed connection system could represent a viable solution to build medium-rise seismic-resistant CLT structures, that minimise damage to structural and non-structural elements and the cost of repair.
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Effects of Heavy Topping on Vibrational Performance of Cross-Laminated Timber Floor Systems

https://research.thinkwood.com/en/permalink/catalogue2708
Year of Publication
2020
Topic
Acoustics and Vibration
Material
CLT (Cross-Laminated Timber)
Application
Floors
Author
Schwendy, Benjamin
Publisher
Clemson University
Year of Publication
2020
Country of Publication
United States
Format
Thesis
Material
CLT (Cross-Laminated Timber)
Application
Floors
Topic
Acoustics and Vibration
Keywords
Vibration Serviceability
Concrete Topping
Panels
Insulation
Language
English
Research Status
Complete
Summary
Cross-Laminated Timber (CLT) is gaining momentum as a competitor to steel and concrete in the construction industry. However, with CLT being relatively new to North America, it is being held back from realizing its full potential by a lack of research in various areas, such as vibration serviceability. This has resulted in vague design guidelines, leading to either overly conservative designs, hurting profit margins, or leading to overly lenient designs, resulting in occupancy discomfort. Eliminating these design inefficiencies is paramount to expanding the use of CLT and creating a more sustainable construction industry. This thesis focuses on the effect of a heavy topping, in this case 2" of concrete over a layer of rigid insulation, on a CLT floor. To this end, modal analysis was performed on two spans of three CLT panels in the Andy Quattlebaum Outdoor Education Center at Clemson University. By performing a series of instrumented heel-drop tests with a roving grid of accelerometers, the natural frequencies, mode shapes, frequency response functions, and damping coefficients were determined. By comparing the results to several different numerical models, the most appropriate model was selected for use in future design. In addition, a walking excitation test was performed to calculate the root mean square acceleration of the floor for comparison to current design standards. This study found that, with a layer of rigid insulation separating the topping and the panel, the system behaved predictably like a non-composite system. The resultant mode shapes also verified that the boundary conditions behaved very close to “hinged” and showed that the combination of the surface splines and the continuous topping provide significant transverse continuity in terms of response to vibrations. Lastly, the results of the walking excitation test showed that, with some further study, the current design standards for steel vibration serviceability can be applied to great effect to CLT systems.
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Dynamic Response of Cross Laminated Timber Floors Subject to Internal Loads

https://research.thinkwood.com/en/permalink/catalogue2716
Year of Publication
2020
Topic
Design and Systems
Mechanical Properties
Material
CLT (Cross-Laminated Timber)
Application
Floors
Author
Skoglund, Jacob
Publisher
Lund University
Year of Publication
2020
Format
Thesis
Material
CLT (Cross-Laminated Timber)
Application
Floors
Topic
Design and Systems
Mechanical Properties
Keywords
Internal Loads
Finite Element Method (FEM)
Panels
Seven-Layer Model
Modal Analysis
3D Model
2D Model
Language
English
Research Status
Complete
Summary
The deregulation of timber for use in large scale constructions has seen the addition of new innovative timber-based products to a category of products referred to as engineered wood products. A now well established addition to these products is cross laminated timber, or CLT for short. CLT products use a form of orthogonal layering, where several parallel wooden boards are arranged in a number of layers, each layer being orthogonal to the previous. The use of orthogonal layering allows for increased stiffness in the two plane directions, resulting in a lightweight construction product with high load bearing capacity and stiffness. To evaluate the dynamic behaviour of structures, engineers commonly apply the finite element method, where a system of equations are solved numerically. Given a sufficient amount of computational power and time, the finite element method can help to solve most dynamical problems. For sufficiently large or complex structures the amount of resources needed may be outside the scope of possibility or feasibility for many. Therefore, evaluating the usage of certain design simplifications, such as omitting to models aspects of the geometry, or alternative forms of analysis for CLT panels may help to reduce the time and resources required for an analysis. In this Master's dissertation, a seven-layer CLT-panel has been created. In the model, each individual board and the gaps between the boards are modelled. The seven-layer model is used as a reference to evaluate the possibility of using less detailed alternative models. The alternative models are created as a layered 3D model and a composite 2D model, both models omit the modelling of the individual laminations, resulting in the layers being solid. The results show small errors for the alternative models when using modal analysis. Concluding that the modal behaviour and dynamic response of a CLT panel can be evaluated using a composite 2D model or a less-detailed layered 3D model. This significantly reduces the amount of time and computational power needed for an analysis, and clearly indicates the benefit of using alternative less detailed models.
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Edge Connection Technology for Cross Laminated Timber (CLT) Floor Slabs Promoting Two-Way Action

https://research.thinkwood.com/en/permalink/catalogue2718
Year of Publication
2020
Topic
Connections
Material
CLT (Cross-Laminated Timber)
Application
Floors
Author
Asselstine, Julian
Publisher
University of British Columbia
Year of Publication
2020
Country of Publication
Canada
Format
Thesis
Material
CLT (Cross-Laminated Timber)
Application
Floors
Topic
Connections
Keywords
Bending
Two-Way
Self-Tapping Screws
Stiffness
Modulus of Elasticity
Language
English
Research Status
Complete
Summary
Cross-laminated timber (CLT) is a class of engineered wood product with the ability to act as a flat plate floor system transferring loads in two-directions due to the orthogonally crossed layers. Currently, dimensional limitations from manufacturing and transportation limit the minor span to about 3.0 m. This results in under utilization of the bending properties of the cross-layers or the choice of a different product because of the common use of one-way bending support conditions such as drop beams simply supporting the ends of the longer span. This study investigates the performance of a newly developed edge connection system to maintain continuity in the minor direction span of CLT and promote two-way bending action. Three connections utilizing a tension splice fastened to the underside of the panel edges with self-tapping screws are investigated, with experimental results showing promise to maintain a high level of stiffness. This connection system was placed in the maximum moment location of the minor span - attaining a connected span modulus of elasticity up to 1.17 times the intact span modulus of elasticity, indicating a reinforcing effect created by the connection. Further, the minor direction span is additionally stiffened through the use of parallel-strand lumber rim beams fixed to the edges of the CLT in the minor direction span and hidden within the cross-section of the CLT. ANSYS finite element modelling calibrated and validated from the experimental results show the potential of this flat-plate system using 5-layer CLT to reach column spacing of 6.0 m by 6.0 m limited by deflection under a serviceability limit state uniformly distributed load of 3.25 kPa. This claim maintains a high degree of conservatism, as the boundary stress obtained from the minimum observed failure load is greater than 6 times the maximum stress at an ultimate limit state load of 4.67 kPa. This system has the ability to expand the flexibility for designers to utilize CLT more efficiently and create large open floor spaces uninhibited by drop-beams.
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262 records – page 1 of 14.