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Lateral Load Resisting Systems for Engineered Wood Construction

https://research.thinkwood.com/en/permalink/catalogue2637
Year of Publication
2009
Topic
Design and Systems
Wind
Seismic
Material
Glulam (Glue-Laminated Timber)
Application
Frames
Author
Popovski, Marjan
Organization
FPInnovations
Year of Publication
2009
Format
Report
Material
Glulam (Glue-Laminated Timber)
Application
Frames
Topic
Design and Systems
Wind
Seismic
Keywords
Lateral Load Resisting System
Construction
Research Status
Complete
Summary
The main sources of lateral loads on buildings are either strong winds or earthquakes. These lateral forces are resisted by the buildings’ Lateral Load Resisting Systems (LLRSs). Adequate design of these systems is of paramount importance for the structural behaviour in general. Basic procedures for design of buildings subjected to lateral loads are provided in national and international model building codes. Additional lateral load design provisions can be found in national and international material design standards. The seismic and wind design provisions for engineered wood structures in Canada need to be enhanced to be compatible with those available for other materials such as steel and concrete. Such design provisions are of vital importance for ensuring a competitive position of timber structures relative to reinforced concrete and steel structures. In this project a new design Section on Lateral Load Resisting Systems was drafted and prepared for future implementation in CSA O86, the Canadian Standard for Engineering Design in Wood. The new Section was prepared based on gathering existing research information on the behaviour of various structural systems used in engineered wood construction around the world as well as developing in-house research information by conducting experimental tests and analytical studies on structural systems subjected to lateral loads. This section for the first time tried to link the system behaviour to that of the connections in the system. Although the developed Section could not have been implemented in CSA O86 in its entirety during the latest code cycle that ended in 2008, the information it contains will form the foundation for future development of technical polls for implementation in the upcoming editions of CSA O86. Some parts of the developed Section were implemented in the 2009 edition of CSA O86 as five separate technical polls. The most important technical poll was the one on Special Seismic Design Considerations for Shearwalls and Diaphragms. This technical poll for the first time in North America includes partial capacity design procedures for wood buildings, and represents a significant step forward towards implementing full capacity-based seismic design procedures for wood structures. Implementation of these design procedures also eliminated most of the confusion and hurdles related to the design of wood-based diaphragms according to 2005 National Building Code of Canada. In other polls, the limit for use of unblocked shearwalls in CSA O86 was raised to 4.8 m, and based on the test results conducted during the project, the NLGA SPS3 fingerjoined studs were allowed to be used as substitutes for regular dimension lumber studs in shearwall applications in engineered buildings in Canada. With the US being the largest export market for the Canadian forest products industry, participation at code development committees in the field of structural and wood engineering in the US is of paramount importance. As a result of extensive activities during this project, for the first time one of the AF&PA Special Design Provisions for Wind and Seismic includes design values for unblocked shearwalls that were implemented based on FPInnovations’ research results. In addition, the project leader was involved in various aspects related to the NEESWood project in the US, in part of which a full scale six-storey wood-frame building will be tested at the E-Defense shake table in Miki, Japan in July 2009. Apart from being built from lumber and glued-laminated timber provided from Canada, the building will also feature the innovative Midply wood wall system that was also invented in Canada. The tests are expected to provide further technical evidence for increasing the height limits for platform frame construction in North America. Building construction - Design Earthquakes, Effect on building construction Glued joints - Finger Grading - Lumber Wind loads
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Innovative Engineered Timber Building Systems for Non-Residential Applications, Utilising Timber Concrete Composite Flooring Capable of Spanning Up to 8 to 10m

https://research.thinkwood.com/en/permalink/catalogue1933
Year of Publication
2010
Topic
Market and Adoption
Design and Systems
Cost
Environmental Impact
Mechanical Properties
Material
Timber-Concrete Composite
Application
Floors
Frames
Author
Crews, Keith
John, Stephen
Gerber, Christophe
Buchanan, Andrew
Smith, Tobias
Pampanin, Stefano
Publisher
Forest & Wood Products Australia
Year of Publication
2010
Format
Report
Material
Timber-Concrete Composite
Application
Floors
Frames
Topic
Market and Adoption
Design and Systems
Cost
Environmental Impact
Mechanical Properties
Keywords
Commercial
Non-Residential
New Zealand
Research Status
Complete
Summary
This project has developed technologies for prefabricated structural systems constructed from engineered wood products for floors and building frames, suitable for buildings up to eight stories in height. The project included the design of a virtual multi-storey timber building, a review of commercial flooring systems, and the development of interim design procedures for timber concrete composite (TCC) floors. Compared with either solid concrete or timber floors, TCC floors provide an excellent balance between increased stiffness, reduced weight, better acoustic separation and good thermal mass. Outcomes from the project have confirmed TCC floors as a viable alternative to conventional flooring systems. The life cycle analysis of the virtual timber building has highlighted the potential advantages of timber-based building systems for commercial applications. The project also resulted in the formation of the Structural Timber Innovation Company, a research company that will continue to develop timber building systems in non-residential buildings in Australia and New Zealand.
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Displacement-Based Seismic Design of Timber Structures

https://research.thinkwood.com/en/permalink/catalogue1891
Year of Publication
2011
Topic
Design and Systems
Seismic
Material
CLT (Cross-Laminated Timber)
Glulam (Glue-Laminated Timber)
LVL (Laminated Veneer Lumber)
Other Materials
Application
Wood Building Systems
Walls
Floors
Beams
Columns
Frames
Author
Loss, Cristiano
Publisher
University of Trento
Year of Publication
2011
Format
Thesis
Material
CLT (Cross-Laminated Timber)
Glulam (Glue-Laminated Timber)
LVL (Laminated Veneer Lumber)
Other Materials
Application
Wood Building Systems
Walls
Floors
Beams
Columns
Frames
Topic
Design and Systems
Seismic
Keywords
Direct Displacement-Based Design
Direct-DBD
Full-Scale
Single Family Houses
Multi-Storey
Connections
Research Status
Complete
Notes
Doctoral Thesis (PhD)
Summary
The research is aimed at developing seismic methods for the design and evaluation of the seismic vulnerability of wooden structures, using a displacement-based approach. After a brief introduction on the seismic behaviour of timber structures, the general Direct Displacement-Based Design (Direct-DBD) procedure and the state-of-the-art are presented, with clear reference to the application of the Direct-DBD method to wooden buildings. The strength of the Direct-DBD method is its ability to design structures in a manner consistent with the level of damage expected, by directly relating the response and the expected performance of the structure. The research begins with a description of the procedural aspects of the Direct-DBD method and the parameters required for its application. The research presented focuses on the formulation of a displacement-based seismic design procedure, applicable to one-storey wooden structures made with a portal system. This typology is very common in Europe and particularly in Italy. A series of analytical expressions have been developed to calculate design parameters. The required analytical Direct-DBD parameters are implemented based on the mechanical behaviour of the connections, made with metal dowel-type fasteners. The calibration and subsequent validation of design parameters use a Monte Carlo numerical simulation and outcomes obtained by tests in full-scale. After the description of the Displacement-Based method for one-storey wooden structures, a series of guidelines to extend the Direct-DBD methodology to other types and categories of timber systems are proposed. The thesis presents the case of a multi-storey wood frame construction, which is a simple extension of the glulam portal frame system. Part of this work has been done within the RELUIS Project, (REte dei Laboratori Universitari di Ingegneria Sismica), Research Line IV, which in the years between 2005 and 2008 involved several Italian universities and Italian institutes of research in the development of new seismic design methods. The Project produced the first draft of model code for the seismic design of structures based on displacement (Direct-DBD). This thesis is the background to the section of the model code developed for timber structures.
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Analytical Model to Evaluate the Equivalent Viscous Damping of Timber Structures with Dowel-Type Fastener Connections

https://research.thinkwood.com/en/permalink/catalogue1893
Year of Publication
2012
Topic
Connections
Application
Frames
Author
Loss, Cristiano
Piazza, Maurizio
Zonta, Daniele
Year of Publication
2012
Format
Conference Paper
Application
Frames
Topic
Connections
Keywords
Equivalent Viscous Damping
Moment Resisting Joints
Dowel-Type Connections
Non-linear Dynamic Analysis
Metal Fasteners
Conference
World Conference on Timber Engineering
Research Status
Complete
Notes
July 16-19, 2012, Auckland, New Zealand
Summary
The Equivalent Viscous Damping (EVD) parameter is used to simplify the dynamic problem, passing from a non-linear solution of the system to a simple linear-elastic one. In the case of Direct Displacement-Based seismic Design (DDBD) methods, the EVD value allows direct design of structures, without an iterative computational process. This paper proposes a rational analytical formula to evaluate the EVD value of timber structures with dowel-type metal fastener connections. The EVD model is developed at the ultimate limit state, as a solution of the equilibrium problem related to an inelastic configuration. For a specific joint configuration, the EVD predicted via an analytical model was compared to experimental results. The proposed EVD model was validated using non-linear dynamic analysis on a portal frame, built with dowel-type fasteners arranged in two concentric crowns.
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Direct Displacement-Based Seismic Design of Timber Structures with Dowel-Type Fastener Connections

https://research.thinkwood.com/en/permalink/catalogue1899
Year of Publication
2012
Topic
Seismic
Connections
Application
Frames
Walls
Wood Building Systems
Author
Loss, Cristiano
Piazza, Maurizio
Zonta, Daniele
Publisher
Sociedade Portuguesa de Engenharia Sismica (SPES)
Year of Publication
2012
Format
Conference Paper
Application
Frames
Walls
Wood Building Systems
Topic
Seismic
Connections
Keywords
Direct Displacement-Based Design
Equivalent Viscous Damping
Dowel Type Fastener
Conference
15WCEE
Research Status
Complete
Notes
September 24-28, 2012, Lisbon, Portugal
Summary
The applicability of the Direct Displacement-Based Design (DBD) procedure is strictly related to a priori evaluation of the design displacement and the matching Equivalent Viscous Damping (EVD) of the structure. In this paper we propose analytical models of these design parameters, at the ultimate limit state, for wooden structures built with engineered joints. Experimental results show that the plastic resources and dissipative capabilities of timber structures under earthquake conditions are ensured by the connections between the members. Therefore, the formulation of the design DBD parameters is based on the mechanical model of the single connector and assumes the inelastic deformation of the structure to be concentrated at the joints. The expected non-linear response of the connections can be either ductile or brittle. However, through an appropriate choice of the geometry and strength characteristics of the materials, in the design process we can control the expected ductile behavior of joints.
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Investigating the Performance of Wood Portal Frames as Alternative Bracing Systems in Light-Frame Wood Buildings

https://research.thinkwood.com/en/permalink/catalogue2240
Year of Publication
2012
Topic
Mechanical Properties
Material
LVL (Laminated Veneer Lumber)
LSL (Laminated Strand Lumber)
Application
Frames
Author
Al Mamun, Abdullah
Organization
University of Ottawa
Year of Publication
2012
Format
Thesis
Material
LVL (Laminated Veneer Lumber)
LSL (Laminated Strand Lumber)
Application
Frames
Topic
Mechanical Properties
Keywords
Portal Frames
Shear Walls
FE model
Moment Capacity
Stiffness
Lateral Load
Research Status
Complete
Summary
Light-frame shearwall assemblies have been successfully used to resist gravity and lateral loads, such as earthquake and wind, for many decades. However, there is a need for maintaining the structural integrity of such buildings even when large openings in walls are introduced. Wood portal frame systems have been identified as a potential alternative to meet some aspects of this construction demand. The overarching goal of the research is to develop wood portal frame bracing systems, which can be used as an alternative or in combination with light-frame wood shearwalls. This is done through investigating the behavior of wood portal frames using the MIDPLY shearwall framing technique. A total of 21 MIDPLY corner joint tests were conducted with varying bracing details. Also, a finite element model was developed and compared with test results from the current study as well as studies by others. It was concluded from the corner joint tests that the maximum moment resistance increased with the addition of metal straps or exterior sheathings. The test results also showed a significant increase in the moment capacity and rotational stiffness by replacing the Spruce-Pine Fir (SPF), header with the Laminated Veneer Lumber (LVL) header. The addition of the FRP to the standard wall configuration also resulted in a significant increase in the moment capacity. However, no significant effect was observed on the stiffness properties of the corner joint. The FE model was capable of predicting the behavior of the corner joints and the full-scale portal frames with realistic end-conditions. The model closely predicted the ultimate lateral capacity for all the configurations but more uncertainty was found in predicting the initial stiffness.The FE model used to estimate the behavior of the full-scale portal frames constructed using the MIDPLY framing techniques showed a significant increase in the lateral load carrying capacity when compared with the traditional portal frame. It was also predicted using the full-scale FE model that the lateral load carrying capacity of the MIDPLY portal frame would increase with the addition of the metal straps on exterior faces. A parametric study showed that using a Laminated Strand Lumber (LSL) header increased the lateral load carrying capacity and the initial stiffness of the frames relative to the SPF header. The study also showed that there was an increase in the capacity if high strength metal straps were used. Doubling of the nail spacing at header and braced wall segment had a considerable effect on the lateral capacity of portal frame. Also, the initial stiffness was reduced for all the configurations with the doubling of the nail spacing at the header and braced wall segment in comparison with the reference frame.
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Seismic Performance of a Post-Tensioned LVL Building Subjected to the Canterbury Earthquake Sequence

https://research.thinkwood.com/en/permalink/catalogue157
Year of Publication
2012
Topic
Seismic
Material
LVL (Laminated Veneer Lumber)
Application
Frames
Walls
Wood Building Systems
Author
Smith, Tobias
Carradine, David
Pampanin, Stefano
Ditommaso, Rocco
Carlo Ponzo, Felice
Year of Publication
2012
Format
Conference Paper
Material
LVL (Laminated Veneer Lumber)
Application
Frames
Walls
Wood Building Systems
Topic
Seismic
Keywords
Post-Tensioning
Quasi-Static
Dynamic
Conference
New Zealand Society for Earthquake Engineering Conference
Research Status
Complete
Notes
April 13-15, 2012, Christchurch, New Zealand
Summary
The following paper presents the seismic performance of a two storey post-tensioned Laminated Veneer Lumber (LVL) building during the aftershock sequence following the MW 6.3 Canterbury earthquake that occurred on 22nd February 2011. Composed of post-tensioned walls in one direction and post-tensioned frames in the other, the structure under analysis was originally tested quasi-statically in the structural laboratories of the University of Canterbury (UoC), Christchurch, New Zealand. Following testing the building was demounted and reassembled as the offices of the STIC (Structural Timber Innovation Company) research consortium on the UoC campus with several significant changes being made to convert the building from its initial use as a test specimen into a functioning office structure.
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Free
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Glued Laminated Timber Space Truss Systems

https://research.thinkwood.com/en/permalink/catalogue244
Year of Publication
2012
Topic
Design and Systems
Connections
Material
Glulam (Glue-Laminated Timber)
Application
Frames
Author
Moggio, Nicola
Organization
Lund University
Year of Publication
2012
Format
Thesis
Material
Glulam (Glue-Laminated Timber)
Application
Frames
Topic
Design and Systems
Connections
Keywords
Space Frames
Research Status
Complete
Summary
The research is directed to explore the possible applications of the space frames system in the field of wooden construction, the proposed construction technology can provide ample opportunity even for timber engineering. The aim of the thesis is to prove the possible application of the timber material considering that the design of wood structures is very complex and requires detailed theoretical knowledge accompanied by the intuition and the ability which comes from an understanding of the critical points of the structures. The work is organized into several parts that try to consider all the thematic relating to the design of the specific construction technology and the material particularities.
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Free
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Seismic Design of Timber Buildings with a Direct Displacement-Based Design Method

https://research.thinkwood.com/en/permalink/catalogue1904
Year of Publication
2013
Topic
Seismic
Design and Systems
Material
Light Frame (Lumber+Panels)
Application
Frames
Wood Building Systems
Author
Loss, Cristiano
Piazza, Maurizio
Zonta, Daniele
Editor
Cruz, Paulo J.S.
Publisher
CRC Press
Year of Publication
2013
Format
Book/Guide
Material
Light Frame (Lumber+Panels)
Application
Frames
Wood Building Systems
Topic
Seismic
Design and Systems
Keywords
Performance-Based Seismic Design
Direct Displacement-Based Design
Displacement
Damping
Research Status
Complete
Series
Structures and Architecture: Concepts, Applications and Challenges
Summary
Modern seismic design procedures are widely represented by the concept of Performance-Based Seismic Design (PBSD). Direct Displacement-Based Design (DDBD) procedure for PBSD of buildings is considered a very promising method which uses displacement as an input design parameter. The DDBD procedure first codified by Priestley requires an a priori estimate of the design displacement and the associated equivalent viscous damping of the structure, at design performance levels. In this paper, design parameters for the ultimate limit state have been developed for a common construction system for timber buildings. Such parameters are defined as a function of mechanical and geometrical connection configurations.
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Dynamic Behaviour of Dowel-Type Connections Under In-Service Vibration

https://research.thinkwood.com/en/permalink/catalogue884
Year of Publication
2013
Topic
Connections
Serviceability
Acoustics and Vibration
Material
Solid-sawn Heavy Timber
Application
Frames
Beams
Author
Reynolds, Thomas
Organization
University of Bath
Year of Publication
2013
Format
Thesis
Material
Solid-sawn Heavy Timber
Application
Frames
Beams
Topic
Connections
Serviceability
Acoustics and Vibration
Keywords
dowel-type connections
Embedment
Nonlinear Behaviour
Time Dependent Behaviour
Energy Dissipation
Portal Frames
Research Status
Complete
Summary
This study investigated the vibration serviceability of timber structures with dowel-type connections. It addressed the use of such connections in cutting-edge timber structures such as multi-storey buildings and long-span bridges, in which the light weight and flexibility of the structure make it possible that vibration induced by dynamic forces such as wind or footfall may cause discomfort to occupants or users of the structure, or otherwise impair its intended use. The nature of the oscillating force imposed on connections by this form of vibration was defined based on literature review and the use of established mathematical models. This allowed the appropriate cyclic load to be applied in experimental work on the most basic component of a dowel-type connection: a steel dowel embedding into a block of timber. A model for the stiffness of the timber in embedment under this cyclic load was developed based on an elastic stress function, which could then be used as the basis of a model for a complete connector. Nonlinear and time-dependent behaviour was also observed in embedment, and a simple rheological model incorporating elastic, viscoelastic and plastic elements was fitted to the measured response to cyclic load. Observations of the embedment response of the timber were then used to explain features of the behaviour of complete single- and multiple-dowel connections under cyclic load representative of in-service vibration. Complete portal frames and cantilever beams were tested under cyclic load, and a design method was derived for predicting the stiffness of such structures, using analytical equations based on the model for embedment behaviour. In each cyclic load test the energy dissipation in the specimen, which contributes to the damping in a complete structure, was measured. The analytical model was used to predict frictional energy dissipation in embedment, which was shown to make a significant contribution to damping in single-dowel connections. Based on the experimental results and analysis, several defining aspects of the dynamic response of the complete structures, such as a reduction of natural frequency with increased amplitude of applied load, were related to the observed and modelled embedment behaviour of the connections.
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73 records – page 1 of 8.