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25 records – page 1 of 3.

Advanced Quality and In-Service Condition Assessment Procedures for Mass Timber and Cross-Laminated Timber Products

https://research.thinkwood.com/en/permalink/catalogue2558
Topic
Mechanical Properties
Material
CLT (Cross-Laminated Timber)
Organization
Forest Products Laboratory
Mississippi State University
Material
CLT (Cross-Laminated Timber)
Topic
Mechanical Properties
Keywords
Non-Destructive Evaluation
Bond Performance
Monitoring Techniques
Serviceability
Quality Assurance
Research Status
In Progress
Notes
Project contacts are Frederico França at Mississippi State University and Robert J. Ross at the Forest Products Laboratory
Summary
With the rapid development of CLT manufacturing capacity around the world and the increasing architectural acceptance and adoption, there is a current and pressing need regarding adhesive bond quality assurance in manufacturing. As with other engineered glued composites, adhesive bondline performance is critically important. Bondline assessment requires technology in the form of sensors, ultrasonics, load cells, or other means of reliable machine evaluation. The objectives of this cooperative study are to develop quality assurance procedures for monitoring the quality of mass timber and CLT during and after manufacturing and to develop assessment techniques for CLT panels in-service.
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Basis of Design - Performance-Based Design and Structural CD Drawings for Framework Office Building in Portland, OR

https://research.thinkwood.com/en/permalink/catalogue1827
Year of Publication
2017
Topic
Design and Systems
Material
CLT (Cross-Laminated Timber)
Glulam (Glue-Laminated Timber)
Application
Wood Building Systems
Organization
KPFF Consulting Engineers
Year of Publication
2017
Format
Report
Material
CLT (Cross-Laminated Timber)
Glulam (Glue-Laminated Timber)
Application
Wood Building Systems
Topic
Design and Systems
Keywords
Structural
Wind Load
Sustainability
Reliability
Seismic
Earthquake Resistance
Serviceability
Design
Research Status
Complete
Series
Framework: An Urban + Rural Design
Notes
Document includes 100% CD construction drawings
Summary
This document outlines the basis of design for the performance-based design and nonlinear response history analysis of the Framework Project in Portland, OR. It is intended to be a living document that will be modified and revised as the project develops and in response to peer review comments. Performance-based design is pursued for this project because the proposed lateral force-resisting system, consisting of post-tensioned rocking cross-laminated timber (CLT) walls is not included in ASCE/SEI 7-10 Table 12.2-1. Lateral force-resisting systems included in ASCE/SEI 7-10 Table 12.2-1 may be designed for earthquake effects using the prescriptive provisions in ASCE/SEI 7- 10. Lateral force-resisting systems not included are still permitted but must be demonstrated to have performance not less than that expected for included systems. This option is available via the performance-based procedures of ASCE/SEI 7-10 Section 1.3.1.3. Note that lateral forceresisting systems for wind effects are not restricted in ASCE/SEI 7-10. Therefore, design for wind effects will still be approached within the performance-based design framework but in a more state-of-the-practice manner.
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Free
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Basis of Design Principles for Timber Structures

https://research.thinkwood.com/en/permalink/catalogue1939
Year of Publication
2018
Topic
Serviceability
Design and Systems
Material
CLT (Cross-Laminated Timber)
Author
Abeysekera, Ishan
Baravalle, Michele
Brandner, Reinhard
Colling, François
Fink, Gerhard
Hamm, Patricia
Hochreiner, Georg
Honfi, Dániel
Ilharco, Tiago
Jockwer, Robert
Kleinhenz, Miriam
Kohler, Jochen
Lawrence, Andrew
Marcroft, Julian
Mikoschek, Michael
Toratti, Tomi
Editor
Fink, Gerhard
Honfi, Dániel
Kohler, Jochen
Dietsch, Philipp
Publisher
COST (European Cooperation in Science and Technology)
Year of Publication
2018
Format
Book/Guide
Material
CLT (Cross-Laminated Timber)
Topic
Serviceability
Design and Systems
Keywords
Eurocode
Deflection
Vibrations
Serviceability Limit States
Eurocode 5
Dowel Type Fastener
Failure Behavior
Research Status
Complete
Summary
This report represents the results of the activities performed in working group 1, Basis of Design. The most important task of working group 1 was the defragmentation and harmonization of techniques and methods that are necessary to prove the reliable, safe and economic application of timber materials or products in the construction industry. This report is structured into five parts. At first general principles regarding the design formats are addressed (Part I). Afterwords timber specific aspects regarding code calibration (Part II) and serviceability (Part III) are summarized. In Part IV other demanding issues for the implementation into Eurocode 5 are addressed. Here also summaries of joint activities with other working groups on cross laminated timber and timber connections are presented. The report concludes with a guideline for data analysis (Part V).
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Connection Performance for LVL-Concrete Composite Floor System

https://research.thinkwood.com/en/permalink/catalogue292
Year of Publication
2015
Topic
Connections
Mechanical Properties
Material
LVL (Laminated Veneer Lumber)
Timber-Concrete Composite
Application
Floors
Author
Fong Lee, Yen
Abd. Ghafar, Nor
Abd. Rahman, Norashidah
Yeoh, David
Organization
International Integrated Engineering Summit (IIES)
Year of Publication
2015
Format
Conference Paper
Material
LVL (Laminated Veneer Lumber)
Timber-Concrete Composite
Application
Floors
Topic
Connections
Mechanical Properties
Keywords
Push-Out
Notch Connections
Failure
Strength
Stiffness
Ultimate Limit States
Serviceability Limit States
Conference
IIES 2014
Research Status
Complete
Notes
December 1-4, 2014, Johor, Malaysia
Summary
The LVL-concrete composite (LCC) structure is a hybrid in system which the LVL member is well connected to the concrete slab by a connector to produce composite action. Various types of connector with different stiffness and shear capacity are available in the market currently. The stiffness of the connector is identified through the push-out experiment. The notch connections for LVL concrete composite beams have higher stiffness and strength compared to mechanical fasteners. This paper discusses the experimental results of symmetrical push-out tests on 3 different types of connector, 150mm rectangular notch with 10mm diameter screw, 100mm rectangular notch with 8mm diameter screw and 100mm triangular notch with 8mm diameter screw. The experimental test was shear push out to failure and the type of failure was discussed. The 150mm rectangular notch was found to be strongest among all and low cost. The 100mm rectangular notch was found to be slightly stiffer than 100mm triangular notch but 100mm triangular notch is easier to construct with only 2 cut. The maximum strength and stiffness at ultimate limit states and serviceability limit states of each type of connection were discussed in this paper.
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Cross Laminated Timber Construction for Resisting Lateral Loads on Six Level Buildings

https://research.thinkwood.com/en/permalink/catalogue1846
Year of Publication
2018
Topic
Design and Systems
Material
CLT (Cross-Laminated Timber)
Application
Walls
Floors
Wood Building Systems
Author
Chapman, John
Publisher
New Zealand Timber Design Society
Year of Publication
2018
Format
Journal Article
Material
CLT (Cross-Laminated Timber)
Application
Walls
Floors
Wood Building Systems
Topic
Design and Systems
Keywords
Resistance
Lateral Load
Stress
Serviceability
Shear
Research Status
Complete
Series
New Zealand Timber Design Journal
Summary
The author’s intention is to contribute to the general discussion on timber multi-level commercial buildings. Interest in this topic is expected due to the environmental advantages of timber construction when compared to concrete and steel. This paper looks into three timber based systems for resisting lateral loads for buildings to six storeys, that will ensure relatively ‘open’ floor spaces. In this paper, three proposed lateral load resisting systems are termed ‘frame’, ‘circular core’, and ‘shear walls’. Only low stresses occur in the three systems and they can be made with timber below ‘structural grade’ which is more economical. The concept of reinforced concrete ‘socket’ foundations, for returning columns to their original locations, is briefly explained. The paper considers the lateral load resisting systems from the viewpoints of structure, architecture and economics. Architecturally, the most flexible arrangement would be a ‘frame’ system on each external wall. It would leave the floor areas free except for internal columns; and windows can be placed within the frame construction allowing light to enter the building. Assumptions have been made, such as the deflections due to joint slippages and these will, at some stage, need to be studied and their accuracy checked.
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Development of Creep Deformations during Service Life: A Comparison of CLT and TCC Floor Constructions

https://research.thinkwood.com/en/permalink/catalogue2955
Year of Publication
2022
Topic
Mechanical Properties
Material
CLT (Cross-Laminated Timber)
Timber-Concrete Composite
Application
Floors
Author
Binder, Eva
Derkowski, Wit
Bader, Thomas
Organization
Linnæus University
Editor
Brandner, Reinhard
Publisher
MDPI
Year of Publication
2022
Format
Journal Article
Material
CLT (Cross-Laminated Timber)
Timber-Concrete Composite
Application
Floors
Topic
Mechanical Properties
Keywords
Serviceability Limit State
Gamma Method
Linear Viscoelasticity
Research Status
Complete
Series
Buildings
Summary
Cross-laminated timber (CLT) slabs in residential buildings need additional weight, e.g., in the form of screeds or gravel layers, to fulfill the criterion for the highest impact-sound class. The additional mass is, however, not exploited for the load bearing behavior, but adds additional weight and leads to an increased height of the floor construction. In this study, such a CLT floor construction with a construction height of 380 mm is compared with a composite slab consisting of a CLT plate with a concrete layer on top with a floor construction height of 330 mm. The timber concrete composite (TCC) slab has a different creep behavior than the CLT slab. Thus, the development of the time-dependent deflections over the service life are of interest. A straightforward hybrid approach is developed, which exploits advanced multiscale-based material models for the individual composite layers and a standardized structural analysis method for the structural slab to model its linear creep behavior. The introduced approach allows to investigate load redistribution between the layers of the composite structure and the evolution of the deflection of the slab during the service life. The investigated slab types show a similar deflection after 50 years, while the development of the deflections over time are different. The CLT slab has a smaller overall stiffness at the beginning but a smaller decrease in stiffness over time than the investigated TCC slab.
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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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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
Format
Thesis
Material
CLT (Cross-Laminated Timber)
Application
Floors
Topic
Acoustics and Vibration
Keywords
Vibration Serviceability
Concrete Topping
Panels
Insulation
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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Effects of interconnections between timber floor elements: dynamic and static evaluations of structural scale tests

https://research.thinkwood.com/en/permalink/catalogue3113
Year of Publication
2021
Topic
Acoustics and Vibration
Material
Glulam (Glue-Laminated Timber)
Application
Floors
Author
Nesheim, Sveinung
Malo, Kjell Arne
Labonnote, Nathalie
Organization
Norwegian University of Science and Technology
Publisher
Springer
Year of Publication
2021
Format
Journal Article
Material
Glulam (Glue-Laminated Timber)
Application
Floors
Topic
Acoustics and Vibration
Keywords
Closed Hollow Section
Interconnection
Cyclic Loading Experiments
Point-load Deflection
Vibration Serviceability Performance
Research Status
Complete
Series
European Journal of Wood and Wood Products
Summary
Long-span timber floor elements increase the flexibility of a building and exhibit a significant market potential. Timber floor elements are endeavouring to fulfil this potential, but building projects employing long-span timber floors have encountered drawbacks. High costs and vibration performance are challenging, and the timber industry is under substantial pressure to find attractive solutions for building components with otherwise favourable environmental features. Only a few existing studies have investigated serviceability sensitivity in relation to timber floor connections. Interconnections are inexpensive to produce and install and may offer a resource-efficient approach to improving serviceability performance. In the present study, the effect of interconnections is investigated in a full-scale structural test. Floor elements positioned in different configurations have been tested for static and dynamic performance using different types of interconnections. The observed effects of interconnection types vary according to the configuration and direction of mode shapes, and are assessed in terms of shift in frequency, damping and resonant energy. These can all be utilised in combination with observed differences in the deflection parameter. The present work demonstrates that connections between timber elements have significant effects on timber floor serviceability and may offer interesting solutions to improve the vibration performance of long-span timber floors.
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Free
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Engineers’ Views on Serviceability in Timber Buildings

https://research.thinkwood.com/en/permalink/catalogue858
Year of Publication
2015
Topic
Serviceability
Application
Wood Building Systems
Author
Näslund, Ida
Organization
Luleå University of Technology
Year of Publication
2015
Format
Report
Application
Wood Building Systems
Topic
Serviceability
Keywords
Stabilisation
Stiffness
Deformation
Serviceability Limit State
Mid-Rise
Dynamic Properties
Research Status
Complete
Summary
Higher timber buildings are produced around the world. The interest for higher timber buildings has increased. Design in ultimate limit state is well known, but little focus has been put on serviceability limit state especially on higher timber buildings. In this report result from interviews with structural engineers/designers, timber frame suppliers, and development managers are presented. The focus has been on serviceability limit state in mid-rise timber buildings. The experience and knowledge with the respondents varies, which has given a wide perspective of the area
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25 records – page 1 of 3.