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Lateral Load Resistance of Cross-Laminated Wood Panels

https://research.thinkwood.com/en/permalink/catalogue2150
Year of Publication
2010
Topic
Connections
Seismic
Material
CLT (Cross-Laminated Timber)
Application
Walls
Author
Popovski, Marjan
Schneider, Johannes
Schweinsteiger, Matthias
Year of Publication
2010
Format
Conference Paper
Material
CLT (Cross-Laminated Timber)
Application
Walls
Topic
Connections
Seismic
Keywords
Quasi-Static Tests
Seismic Performance
Screws
Nails
Steel Brackets
Timber Rivets
Conference
World Conference on Timber Engineering
Research Status
Complete
Summary
In this paper, some of the results are presented from a series of quasi-static tests on CLT wall panels conducted at FPInnovation-Forintek in Vancouver, BC. CLT wall panels with various configurations and connection details were tested. Wall configurations included single panel walls with three different aspect ratios, multi-panel walls with step joints and different types of screws to connect them, as well as two-storey wall assemblies. Connections for securing the walls to the foundation included: off-the-shelf steel brackets with annular ring nails, spiral nails, and screws; combination of steel brackets and hold-downs; diagonally placed long screws; and custom made brackets with timber rivets. Results showed that CLT walls can have adequate seismic performance when nails or screws are used with the steel brackets. Use of hold-downs with nails on each end of the wall improves its seismic performance. Use of diagonally placed long screws to connect the CLT walls to the floor below is not recommended in high seismic zones due to less ductile wall behaviour. Use of step joints in longer walls can be an effective solution not only to reduce the wall stiffness and thus reduce the seismic input load, but also to improve the wall deformation capabilities. Timber rivets in smaller groups with custom made brackets were found to be effective connectors for CLT wall panels. Further research in this field is needed to further clarify the use of timber rivets in CLT.
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Preliminary Assessment of Hygrothermal Performance of Cross-Laminated Timber Wall Assemblies Using Hygrothermal Models

https://research.thinkwood.com/en/permalink/catalogue2628
Year of Publication
2010
Topic
Moisture
Design and Systems
Serviceability
Material
CLT (Cross-Laminated Timber)
Light Frame (Lumber+Panels)
Application
Walls
Author
Wang, J.
Baldracchi, P.
Organization
FPInnovations
Year of Publication
2010
Format
Report
Material
CLT (Cross-Laminated Timber)
Light Frame (Lumber+Panels)
Application
Walls
Topic
Moisture
Design and Systems
Serviceability
Keywords
Hygrothermal
Moisture Performance
Rainscreen
Research Status
Complete
Summary
Preliminary simulation was carried out using hygIRC and WUFI, both 1-D hygrothermal models, to analyze moisture performance of rainscreened wood-frame walls and cross-laminated timber (CLT) walls for the climates in Vancouver and Calgary. The major results are as follows. In order to provide baseline knowledge, preliminary comparisons between hygIRC and WUFI were conducted to investigate the effects of climate data, wall orientations and rain intrusion on the performance of the rainscreened wood-frame walls based on Vancouver’s climate. hygIRC tended to produce almost constant moisture content (MC) of the plywood sheathing throughout a year but WUFI showed greater variations, particularly when the ventilation of the rainscreen cavity was neglected. Rainscreen cavity ventilation provided dramatic drying potentials for wall assemblies based on the WUFI simulation. hygIRC indicated that east-facing walls had the highest moisture load, but the differences between orientations seemed negligible in WUFI when the rainscreen cavity ventilation was taken into account. When 1% of wind-driven rain was simulated as an additional moisture load, hygIRC suggested that the rainscreen walls could not dry out in Vancouver, WUFI, however, indicated that they could dry to a safe MC level in the summer. The discrepancies in material property data between the two models and between different databases in WUFI (even for the same wood species) were found to be very large. In terms of wood sorption data, large differences existed at near-saturated RH levels. This is a result of using pressure-plate/membrane methods for measuring material equilibrium moisture content (EMC) under high RH conditions. The EMC of wood at near-100% RH conditions measured with these methods can be higher than 200%, suggesting wood in construction would decay without liquid water intrusion or severe vapour condensation. The pressure-plate/membrane methods also appeared to be highly species-dependent, and have higher EMC at a certain RH level for less permeable species, from which it is relatively difficult to remove water during the measurement. The hygrothermal simulation in this work suggested that such a species bias caused by testing methods could put impermeable species (most Canadian species) at a disadvantage to permeable species like southern pine during related durability design of building assemblies. In terms of using CLT for construction in Vancouver and Calgary, the WUFI simulations suggested that the use of less permeable materials such as EPS (expanded polystyrene insulation), XPS (extruded polystyrene insulation), self-adhered bituminous membrane and polyethylene in wall assemblies reduced the ability of the walls to dry. On the other hand, permeable assemblies such as those using relatively permeable insulation like semi-rigid mineral wool (rock wool) as exterior insulation, instead of less permeable exterior insulation materials, would help walls dry. The simulation also suggested that using CLT products with initially low MC would significantly reduce moisture-related risks, which indicated the importance of protecting CLT and avoiding wetting during transportation and construction. In addition, the simulation found that indoor relative humidity (RH) conditions generated by the indoor RH prediction models included in hygIRC and WUFI varied greatly under the same basic climate and building conditions. The intermediate method specified in ASHRAE Standard 160 P resulted in long periods of saturated RH conditions throughout a year for the Vancouver climate, which may not be representative of ordinary residential buildings in Vancouver. The simulation in this study is preliminary and exploratory. It would be arbitrary to recommend one model over the other based on this report or use the simulation results directly for CLT wall assembly design without consultation with building science specialists. However, this work revealed more opportunities for close collaborations between the wood science and the building science communities. More work should be carried out to develop appropriate testing methods and assemble material property data for hygrothermal simulation of wood-based building assemblies. Model improvement and field verification are also strongly recommended, particularly for new building systems such as CLT constructions.
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Accommodating Movement in High-Rise Wood-Frame Building Construction

https://research.thinkwood.com/en/permalink/catalogue1875
Year of Publication
2011
Topic
Design and Systems
Connections
Material
Steel-Timber Composite
Other Materials
LVL (Laminated Veneer Lumber)
Application
Wood Building Systems
Floors
Walls
Author
Howe, Richard
Publisher
Forest Products Society
Year of Publication
2011
Format
Journal Article
Material
Steel-Timber Composite
Other Materials
LVL (Laminated Veneer Lumber)
Application
Wood Building Systems
Floors
Walls
Topic
Design and Systems
Connections
Keywords
Detailing
Shrinkage
Differential Movement
Research Status
Complete
Series
Wood Design Focus
Summary
Ease of construction and favorable overall costs relative to other construction types are making high-rise (i.e., 4- and 5-story) wood frame construction increasingly popular. With these buildings increasing in height, there is a greater impetus on designers to address frame and finishes movement in such construction. As we all know, buildings are dynamic creatures experiencing a variety of movements during construction and over their service life. In wood frame construction, it is important to consider not only absolute movement but also differential movement between dissimilar materials. This article focuses on differential movement issues and how to recognize their potential and avoid problems by effective detailing.
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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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Predicting the Fire Resistance of Cross-Laminated Timber Assemblies

https://research.thinkwood.com/en/permalink/catalogue1865
Year of Publication
2012
Topic
Fire
Material
CLT (Cross-Laminated Timber)
Application
Walls
Wood Building Systems
Author
Craft, Steven
Desjardins, Richard
Bénichou, Noureddine
Organization
National Research Council of Canada
Publisher
National Research Council Canada. Construction
Year of Publication
2012
Format
Report
Material
CLT (Cross-Laminated Timber)
Application
Walls
Wood Building Systems
Topic
Fire
Keywords
Fire Resistance
Assembly
Panels
Full-Scale Fire Test
Full-Scale
Research Status
Complete
Summary
There is growing interest from the Canadian wood products industry to produce and use cross-laminated timber (CLT) panels in construction. Because this is a new product in North America, there is a need to demonstrate that the product meets various performance attributes such as structural resistance, sound transmission and fire resistance. This research aims to address two primary objectives which will support the North American adoption of CLT. First, a generic calculation method for determining the fire-resistance of CLT assemblies is needed to enable producers to manufacture a number of different configurations of panels without the need to run a large number of full-scale fire tests. Second, the CLT assemblies chosen for testing have been identified as the most likely configurations to be used thereby providing test data to support the claims of fire-resistance to help satisfy the authority having jurisdiction.
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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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Seismic Behaviour of Cross-Laminated Timber Structures

https://research.thinkwood.com/en/permalink/catalogue2151
Year of Publication
2012
Topic
Seismic
Connections
Mechanical Properties
Material
CLT (Cross-Laminated Timber)
Application
Walls
Author
Popovski, Marjan
Karacabeyli, Erol
Year of Publication
2012
Format
Conference Paper
Material
CLT (Cross-Laminated Timber)
Application
Walls
Topic
Seismic
Connections
Mechanical Properties
Keywords
Seismic Resistance
Force Modification Factors
Quasi-Static Tests
National Building Code of Canada
Conference
World Conference on Timber Engineering
Research Status
Complete
Summary
European experience shows that besides single family housing, Cross-Laminated Timber (CLT) can be competitive in mid-rise and high-rise buildings. Although this system has not been used to the same extent so far in North America, it can be viable wood structural solution for the shift towards sustainable densification of urban and suburban centres. FPInnovations has undertaken a multidisciplinary project on determining the structural properties of a typical CLT construction, including quantifying the seismic resistance and force modification factors of CLT buildings. In this paper, some of the results from a series of quasi-static tests on CLT wall panels are presented as well as preliminary estimates for the force modification factors (R-factors) for seismic design of CLT structures. CLT wall panels with various configurations and connection details were tested. Wall configurations included single panels without openings with three different aspect ratios, panels with openings, as well as multi-panel walls with step joints and fasteners between them. Connections for securing the walls to the foundation included off-the-shelf steel brackets with annular ring nails, spiral nails, and screws; a combination of steel brackets and hold-downs; and custom made brackets with timber rivets. Results from two storey configurations that include two walls and a CLT slab in between are presented and discussed. Finally preliminary estimates and recommendations for the force modification factors (R-factors) for seismic design of CLT structures according to National Building Code of Canada (NBCC) are also made.
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Free
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Carterton Events Centre Auditorium Pres-Lam Wall Design and Construction

https://research.thinkwood.com/en/permalink/catalogue38
Year of Publication
2012
Topic
Seismic
Material
LVL (Laminated Veneer Lumber)
Application
Wood Building Systems
Shear Walls
Author
Dekker, Dave
Chung, Stanley
Palermo, Alessandro
Year of Publication
2012
Format
Conference Paper
Material
LVL (Laminated Veneer Lumber)
Application
Wood Building Systems
Shear Walls
Topic
Seismic
Keywords
Lateral Loads
Post-Tensioned
Pres-Lam
Sustainability
Conference
New Zealand Society for Earthquake Engineering Conference
Research Status
Complete
Notes
April 13-15, 2012, Christchurch, New Zealand
Summary
Driven by sustainability, locally available resources and expertise, and economy, the design of the Carterton Events Centre focused on timber for the majority of the main structural and non-structural components. Combined with a client desire for minimization of earthquake damage, dissipative post-tensioned rocking Laminated Veneer Lumber (LVL) shear walls (Pres-Lam) were considered for the lateral load resisting system. During design development various structural forms were explored and tested through costing to determine an economic design solution meeting the project drivers. Advanced numerical analyses carried out by the University of Canterbury validated the design process assuring confidence with the design of the technology.
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Free
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Experimental-Numerical Analyses of the Seismic Behaviour of Cross-Laminated Wall Systems

https://research.thinkwood.com/en/permalink/catalogue56
Year of Publication
2012
Topic
Seismic
Energy Performance
Material
CLT (Cross-Laminated Timber)
Application
Walls
Author
Gavric, Igor
Rinaldin, Giovanni
Amadio, Claudio
Fragiacomo, Massimo
Ceccotti, Ario
Year of Publication
2012
Format
Conference Paper
Material
CLT (Cross-Laminated Timber)
Application
Walls
Topic
Seismic
Energy Performance
Keywords
Finite Element Model
Abaqus
Experimental
Numerical
Full Scale
Cyclic Testing
Conference
World Conference on Earthquake Engineering
Research Status
Complete
Notes
September 24-28, 2012, Lisbon, Portugal
Summary
The paper discusses experimental and numerical seismic analyses of typical connections and wall systems used in cross-laminated (X-Lam) timber buildings. An extended experimental programme on typical X-Lam connections was performed at IVALSA Trees and Timber Institute. In addition, cyclic tests were also carried out on full-scale single and coupled X-Lam wall panels with different configurations and mechanical connectors subjected to lateral force. An advanced non-linear hysteretic spring to describe accurately the cyclic behaviour of connections was implemented in ABAQUS finite element software package as an external subroutine. The FE model with the springs calibrated on single connection tests was then used to reproduce numerically the behaviour of X-Lam wall panels, and the results were compared with the outcomes of experimental full-scale tests carried out at IVALSA. The developed model is suitable for evaluating dissipated energy and seismic vulnerability of X-Lam structures.
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Damage Assessment of Cross Laminated Timber Connections Subjected to Simulated Earthquake Loads

https://research.thinkwood.com/en/permalink/catalogue70
Year of Publication
2012
Topic
Connections
Seismic
Material
CLT (Cross-Laminated Timber)
Application
Shear Walls
Author
Schneider, Johannes
Stiemer, Siegfried
Tesfamariam, Solomon
Karacabeyli, Erol
Popovski, Marjan
Year of Publication
2012
Format
Conference Paper
Material
CLT (Cross-Laminated Timber)
Application
Shear Walls
Topic
Connections
Seismic
Keywords
Damage
Panels
North American Market
Conference
World Conference on Timber Engineering
Research Status
Complete
Notes
July 15-19, 2012, Auckland, New Zealand
Summary
Wood-frame is the most common construction type for residential buildings in North America. However, there is a limit to the height of the building using a traditional wood-frame structure. Cross-laminated timber (CLT) provides possible solutions to mid-rise and high-rise wood buildings. CLT offers many advantages such as improved dimensional stability, a quicker erection time and good performance in case of fire. In order to introduce the cross-laminated timber products to the North American market, it is important to gain a comprehensive understanding of its structural properties. This paper focuses on the seismic performance of CLT connections. Over the last few years FPInnovations of Canada has conducted a test program to determine the structural properties of CLT panels and its application in shear walls. The test program comprised of more than 100 connection tests which followed the loading procedures of CUREE and ISO test protocols as specified in ASTM Standards ASTM E 2126-09 (2009). These tests were performed parallel and perpendicular to the grain of the outer layer, respectively. The impact of different connections on the seismic performance of CLT walls was investigated in a second phase on full size shearwall. CLT panels are relatively stiff and thus energy dissipation must be accomplished through the ductile behaviour of connections between different shear wall elements and the connections to the story below. A literature review on previous research work related to damage prediction and assessment for wood frame structures was performed. Different approaches for damage indices were compared and discussed. This paper describes how the energy-based cumulative damage assessment model was calibrated to the CLT connection and shear wall test data in order to investigate the damage under monotonic and cyclic loading. Comparison of different wall setup provided a deeper insight into the damage estimation of CLT shear walls and determination of the key parameters in the damage formulation. This represents a first published attempt to apply the damage indices to estimate the seismic behaviour of CLT shear walls.
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377 records – page 1 of 38.