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33 records – page 1 of 4.

A Composite System Using Ultra High-Performance Fibre-Reinforced Concrete and Cross-Laminated Timber

https://research.thinkwood.com/en/permalink/catalogue1420
Year of Publication
2016
Topic
Mechanical Properties
Acoustics and Vibration
Connections
Material
CLT (Cross-Laminated Timber)
Timber-Concrete Composite
Application
Floors
Author
Chen, Mengyuan
Organization
University of Toronto
Year of Publication
2016
Format
Thesis
Material
CLT (Cross-Laminated Timber)
Timber-Concrete Composite
Application
Floors
Topic
Mechanical Properties
Acoustics and Vibration
Connections
Keywords
Ultra-High-Performance Fibre-Reinforced Concrete
Push-Out Tests
Glued-In Rods
Bending Tests
Vibration Tests
Span Limits
Research Status
Complete
Summary
The application of cross-laminated timber (CLT) as floor panels is limited by excessive deflection and vibration. A composite system combining CLT and ultra high-performance fibre-reinforced concrete (UHPFRC) was developed to extend span limits. Push-off tests were conducted on different connectors, and a glued-in rod connector was chosen and further refined for the proposed system. Static bending tests and free vibration tests were conducted on bare CLT panels and two composite specimens. By comparing the results, it is concluded that the proposed system considerably extend the span limits of CLT panels.
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Developing a Large Span Timber-based Composite Floor System for Highrise Office Buildings

https://research.thinkwood.com/en/permalink/catalogue2549
Topic
Design and Systems
Material
CLT (Cross-Laminated Timber)
Application
Floors
Hybrid Building Systems
Material
CLT (Cross-Laminated Timber)
Application
Floors
Hybrid Building Systems
Topic
Design and Systems
Keywords
Large Span
Prefabrication
High-Rise
Office Buildings
Tall Timber Buildings
Research Status
In Progress
Notes
Project contact is Frank Lam at the University of British Columbia
Summary
The objective of this project is to develop a large span timber-based composite floor system for the construction of highrise office buildings. This prefabricated floor system could span over 10 m under regular office occupation load, and its use will expedite the construction significantly, converting to multi-million financial savings in a typical 40+ story project, besides the impact on reducing carbon footprint and enhancing living experience.
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Developing a Large Span Timber-based Composite Floor System for Highrise Office Buildings Phase I

https://research.thinkwood.com/en/permalink/catalogue2803
Year of Publication
2021
Topic
Design and Systems
Material
CLT (Cross-Laminated Timber)
LVL (Laminated Veneer Lumber)
LSL (Laminated Strand Lumber)
Glulam (Glue-Laminated Timber)
Application
Floors
Author
Zhang, Chao
Lee, George
Lam, Frank
Organization
University of British Columbia
Year of Publication
2021
Format
Report
Material
CLT (Cross-Laminated Timber)
LVL (Laminated Veneer Lumber)
LSL (Laminated Strand Lumber)
Glulam (Glue-Laminated Timber)
Application
Floors
Topic
Design and Systems
Keywords
Box Girder
Timber Composite Floor
Span
High-Rise
Tall Wood Buildings
Stiffness
Composite Action
Research Status
Complete
Summary
This project proposes a timber-based composite floor that can span 12 m and be used in the construction of 40+ story office buildings. This floor system integrates timber panels and timber beams to form a continuous box girder structure. The timber panels function as the flanges and the timber beams as the web. The beams are spaced and connected to the flange panels so that sufficient bending stiffness of a 12 m span can be achieved via the development of composite action. The current phase of this project studied the performance of the connections between timber elements in the proposed composite member. Six types of connections using different flange material and connection techniques were tested: Cross Laminated Timber (CLT), Laminated Strand Lumber (LSL), Laminated Veneer Lumber (LVL), and Post Laminated Veneer Lumber (PLVL). Glulam was used as the web. The majority of the connections used self-tapping wood screws except one had notches. The load-carrying capacity, stiffness, and ductility of the connections were measured. The stiffness of CLT, LSL, and PLVL connections was in the same range, 19-20 kN/mm per screw. Amongst the three, LSL had the highest peak load and PLVL had the highest proportional limit. The stiffness of the two LVL screw connections was around 13 kN/mm. The notched LVL connection had significantly higher stiffness than the rest, and its peak load was in the same range as LSL, but the failure was brittle. LVL was used to manufacture the full scale timber composite floor element. With a spacing of 400 mm, the overall stiffness reached 33689 N
mm2×109, which was 2.5 times the combined stiffness of two Glulam beams. The predicted overall stiffness based on Gamma method was within 5% of the tested value, and the estimated degree of composite action was 68%. From both the test results and analytical modeling, the number of screws may be further reduced to 50% or less of the current amount, while maintaining a high level of stiffness. Future work includes testing the composite floor under different screw spacings, investigating the effect of concrete topping, and the connections between floor members and other structural elements.
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Development of a Slab-on-Girder Wood-Concrete Composite Highway Bridge

https://research.thinkwood.com/en/permalink/catalogue1421
Year of Publication
2012
Topic
Design and Systems
Material
Glulam (Glue-Laminated Timber)
Application
Bridges and Spans
Author
Lehan, Andrew
Organization
University of Toronto
Year of Publication
2012
Format
Thesis
Material
Glulam (Glue-Laminated Timber)
Application
Bridges and Spans
Topic
Design and Systems
Keywords
Ultra-High-Performance Fibre-Reinforced Concrete
Girder
Post-Tensioning
Prefabrication
Durability
Span-to-Depth Ratio
Research Status
Complete
Summary
This thesis examines the development of a superstructure for a slab-on-girder wood-concrete composite highway bridge. Wood-concrete composite bridges have existed since the 1930's. Historically, they have been limited to spans of less than 10 m. Renewed research interest over the past two decades has shown great potential for longer span capabilities. Through composite action and suitable detailing, improvements in strength, stiffness, and durability can be achieved versus conventional wood bridges. The bridge makes use of a slender ultra-high performance fibre-reinforced concrete (UHPFRC) deck made partially-composite in longitudinal bending with glued-laminated wood girders. Longitudinal external unbonded post-tensioning is utilized to increase span capabilities. Prefabrication using double-T modules minimizes the need for cast-in-place concrete on-site. Durability is realized through the highly impermeable deck slab that protects the girders from moisture. Results show that the system can span up to 30 m while achieving span-to-depth ratios equivalent or better than competing slab-on-girder bridges.
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Development of Evaluation Methodology for Rolling Shear Properties in Cross Laminated Timber (CLT)

https://research.thinkwood.com/en/permalink/catalogue137
Year of Publication
2013
Topic
Mechanical Properties
Material
CLT (Cross-Laminated Timber)
Application
Beams
Author
Zhou, Qinyi
Organization
University of New Brunswick
Year of Publication
2013
Format
Thesis
Material
CLT (Cross-Laminated Timber)
Application
Beams
Topic
Mechanical Properties
Keywords
Span-to-Depth
Rolling Shear Modulus
Two-plate shear test
Load Carrying Capacity
Research Status
Complete
Summary
The rolling shear modulus is very low, leading to rolling shear failure in the cross layer of cross-laminated timber (CLT). The overall objective of this thesis work was to develop an appropriate methodology for measuring the rolling shear properties of CL T. This research consists of three article format chapters, which were aimed at: 1) obtaining a better understanding of advantages and disadvantages of using the bending test and twoplate shear test for determining the rolling shear properties of 3-layer CLT, 2) investigating the influence of growth ring orientation and laminates thickness of cross layer on the rolling shear properties, and 3) verifying the feasibility of two-plate shear test method for measuring the rolling shear properties of 3-layer CL T beam. It is recommended that the two-plate shear test be used as a testing method for measuring the rolling shear modulus of a cross layer, which can be used to calculate the deflection of a 3-layer CLT beam using the shear analogy method at a given span-to-depth ratio ranging from 6 to 50. An adjustment factor (a) was proposed to predict the deflection under the centre-point bending test at various span-to-depth ratios. The two-plate shear test method can also be used to measure the rolling shear strength, and can provide a reasonable estimate of the load-carrying capacity of 3-layer CLT beam at a relatively large span-to-depth ratio, but a conservative estimate at a small span-to-depth ratio. In summary, it shall be feasible to adopt the two-plate shear test for determining the rolling shear modulus and strength of cross layer in CLT.
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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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Dynamic Performance of Timber and Timber-Concrete Composite Flooring Systems

https://research.thinkwood.com/en/permalink/catalogue229
Year of Publication
2013
Topic
Connections
Serviceability
Material
LVL (Laminated Veneer Lumber)
Timber-Concrete Composite
Application
Floors
Author
Rijal, Rajendra
Organization
University of Technology Sydney
Year of Publication
2013
Format
Thesis
Material
LVL (Laminated Veneer Lumber)
Timber-Concrete Composite
Application
Floors
Topic
Connections
Serviceability
Keywords
Connections
Costs
Fasteners
Finite Element Model
Long Span
Multi-Storey
Sustainability
Vibrations
Small Scale
Static Load Tests
Damage Index (DI) Method
Loss of Composite Action Index (LCAI)
Research Status
Complete
Summary
The work presented in this thesis deals with the investigation of the dynamic performance of timber only and TCC flooring systems, which is one of the sub-objectives of the research focus at UTS. In particular, the presented research assesses the dynamic performance of long-span timber and TCC flooring systems using different experimental und numerical test structures. For the experimental investigations, experimental modal testing and analysis is executed to determine the modal parameters (natural frequencies, damping ratios and mode shapes) of various flooring systems. For the numerical investigations, finite element models are calibrated against experimental results, and are utilised for parametric studies for flooring systems of different sizes. Span tables are generated for both timber and TCC flooring systems that can be used in the design of long-span flooring systems to satisfy the serviceability fundamental frequency requirement of 8 Hz or above. To predict the fundamental frequency of various TCC beams and timber floor modules (beams), five different analytical models are utilised and investigated. To predict the cross-sectional characteristics of TCC systems and to identify the effective flexural stiffness of partially composite beams, the “Gamma method” is utilised. [...] two novel methods are developed in this thesis that determines the degree of composite action of timber composite flooring systems using only measurements from non-destructive dynamic testing. The core of both methods is the use of an existing mode-shape-based damage detection technique, namely, the Damage Index (DI) method to derive the loss of composite action indices (LCAIs) named as LCAI1 and LCAI2. The DI method utilises modal strain energies derived from mode shape measurements of a flooring system before and after failure of shear connectors. The proposed methods are tested and validated on a numerical and experimental timber composite beam structure consisting of two LVL components (flange and web). To create different degrees of composite action, the beam is tested with different numbers of shear connectors to simulate the failure of connection screws. The results acquired from the proposed dynamic-based method are calibrated to make them comparable to traditional static-based composite action results. It is shown that the two proposed methods can successfully be used for timber composite structures to determine the composite action using only mode shapes measurements from dynamic testing.
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Evaluation of Adhesive Bond Strength of Two-Layer Asymmetric Cross-Laminated LSL Specimens

https://research.thinkwood.com/en/permalink/catalogue1548
Year of Publication
2016
Topic
Connections
Mechanical Properties
Material
CLT (Cross-Laminated Timber)
LSL (Laminated Strand Lumber)
Author
Gong, Meng
Chui, Ying Hei
Li, Ling
Year of Publication
2016
Format
Conference Paper
Material
CLT (Cross-Laminated Timber)
LSL (Laminated Strand Lumber)
Topic
Connections
Mechanical Properties
Keywords
Adhesives
Bond Strength
Short Span
Bending Tests
Two-Component Polyurethane
Polyvinyl Acetate
Conference
World Conference on Timber Engineering
Research Status
Complete
Notes
August 22-25, 2016, Vienna, Austria p. 1185-1190
Summary
Massive timber panels (MTPs) has shown a great potential in construction of tall buildings. Evaluation of the face-bond strength of MTPs is of an interest to use of this kind of products. This study was aimed at developing an appropriate test procedure for evaluating the adhesive bond strength of cross-laminated laminated strand lumber (LSL). Short span bending tests were conducted on two-layer asymmetric cross-laminated LSL specimens, which were adhesively bonded using two-component polyurethane (PUR) and polyvinyl acetate (PVAc). For comparison, block shear specimens were tested as well. It was found that the 2-layer asymmetric cross-laminated specimen assembly under the short span bending could be used to differentiate between good and poor bond quality.
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Evaluation of Timber-Concrete Floor Performance under Occupant-Induced Vibrations using Continuous Monitoring

https://research.thinkwood.com/en/permalink/catalogue131
Year of Publication
2013
Topic
Acoustics and Vibration
Serviceability
Material
LVL (Laminated Veneer Lumber)
Timber-Concrete Composite
Application
Floors
Author
Omenzetter, Piotr
Kohli, Varun
Desgeorges, Yohann
Publisher
Scientific.net
Year of Publication
2013
Format
Journal Article
Material
LVL (Laminated Veneer Lumber)
Timber-Concrete Composite
Application
Floors
Topic
Acoustics and Vibration
Serviceability
Keywords
Damping
Frequencies
Lightweight
Long Span
Office Buildings
Research Status
Complete
Series
Key Engineering Materials
Summary
This paper describes the design of a system to monitor floor vibrations in an office building and an analysis of several months worth of collected data. Floors of modern office buildings are prone to occupant-induced vibrations. The contributing factors include long spans, slender and flexible designs, use of lightweight materials and low damping. As a result, resonant frequencies often fall in the range easily excited by normal footfall loading, creating potential serviceability problems due to undesirable levels of vibrations. This study investigates in-situ performance of a non-composite timber-concrete floor located in a recently constructed innovative multi-storey office building. The floor monitoring system consists of several displacement transducers to measure long-term deformations due to timber and concrete creep and three accelerometers to measure responses to walking forces, the latter being the focus of this paper. Floor response is typically complex and multimodal and the optimal accelerometer locations were decided with the help of the effective independence-driving point residue (EfI-DPR) technique. A novel approach to the EfI-DPR method proposed here uses a combinatorial search algorithm that increases the chances of obtaining the globally optimal solution. Several months worth of data collected by the monitoring system were analyzed using available industry guidelines, including ISO2631-1:1997(E), ISO10137:2007(E) and SCI Publication P354. This enabled the evaluation of the floor performance under real operating conditions.
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Failure Modes and Reinforcement Techniques for Timber Beams – State of the Art

https://research.thinkwood.com/en/permalink/catalogue11
Year of Publication
2015
Topic
Serviceability
Material
Solid-sawn Heavy Timber
Application
Beams
Author
Harte, Annette
Franke, Bettina
Franke, Steffen
Publisher
ScienceDirect
Year of Publication
2015
Format
Journal Article
Material
Solid-sawn Heavy Timber
Application
Beams
Topic
Serviceability
Keywords
Damage
Deterioration
Failure
Fasteners
Large Span
Loading
Reinforcement
Retrofit
Research Status
Complete
Series
Construction and Building Materials
Summary
Highly loaded and large span timber beams are often used for halls, public buildings or bridges. Reinforcement of beams may be required to extend the life of the structure, due to deterioration or damage to the material/product or change of use. The paper summarises methods to repair or enhance the structural performance of timber beams. The main materials/products cross sections and geometries used for timber beam are presented. Furthermore, their general failure modes are described and typical retrofitting and reinforcement techniques are given. The techniques include wood to wood replacements, use of mechanical fasteners and additional strengthening materials/products.
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33 records – page 1 of 4.