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Expanding wood use towards 2025: seismic performance of midply shear walls, year 2

https://research.thinkwood.com/en/permalink/catalogue2917
Year of Publication
2021
Topic
Seismic
Material
Other Materials
Application
Shear Walls
Author
Ni, Chun
Chen, Zhiyong
Organization
FPInnovations
Year of Publication
2021
Format
Report
Material
Other Materials
Application
Shear Walls
Topic
Seismic
Keywords
Sheathing Thickness
Nail Spacing
Lateral Load Capacity
Drift Capacity
Energy Dissipation Capacity
Research Status
Complete
Summary
Midply shear wall, which was originally developed by researchers at Forintek Canada Corp. (predecessor of FPInnovations) and the University of British Columbia, is a high-capacity shear wall system that is suitable for high wind and seismic loadings. Its superior seismic performance was demonstrated in a full-scale earthquake simulation test of a 6-storey wood-frame building in Japan. In collaboration with APA–The Engineered Wood Association and the American Wood Council (AWC), a new framing arrangement was designed in this study to increase the vertical load resistance of midply shear walls and make it easier to accommodate electrical and plumbing services. In this study, a total of 12 midply shear wall specimens in four wall configurations with different sheathing thicknesses and nail spacing were tested under reversed cyclic loading. Test results showed that the modified midply shear walls have approximately twice the lateral load capacity of a comparable standard shear wall. The drift capacity and energy dissipation capability are also greater than comparable standard shear wall. Seismic equivalency to standard shear walls in accordance with ASTM D7989 was also conducted. Results show that an overstrength factor of 2.5 and can be used to assign allowable design strengths of midply shear walls with 7/16” and nail spacing at 4” or 3” on center. For midply shear walls with 19/32” OSB, a higher overstrength factor must be used to meet the ductility criteria. The information from this study will support code implementation of the midply shear walls in Canadian and US timber design standards, thereby providing more design options for light wood frame structures in North America.
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Experimental Testing of Anchoring Devices for Bottom Rail in Partially Anchored Timber Frame Shear Walls with Two-Sided Sheathing

https://research.thinkwood.com/en/permalink/catalogue400
Year of Publication
2012
Topic
Connections
Material
Light Frame (Lumber+Panels)
Application
Shear Walls
Author
Caprolu, Giuseppe
Organization
Luleå University of Technology
Year of Publication
2012
Format
Report
Material
Light Frame (Lumber+Panels)
Application
Shear Walls
Topic
Connections
Keywords
Failure Modes
Sheathing
Research Status
Complete
Summary
Källsner and Girhammar [1] have presented a new plastic design method for wood-framed shear walls at ultimate limit state. This method allows the designer to calculate the load-carrying capacity of shear walls partially anchored, where the leading stud is not fully anchored against uplift. The parameters varied are the size of the washer and the orientation of the pith. The bottom rail was subjected to loading perpendicular to grain through two-sided sheathing. In this report the different set of series are presented. Five sets were conducted depending on the size of the washer and in each set the pith was placed upwards and downwards.
Online Access
Free
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Predicting the Racking Performance of Wood Shear Wall Systems with Insulated Sheathing

https://research.thinkwood.com/en/permalink/catalogue2245
Topic
Design and Systems
Seismic
Energy Performance
Material
Light Frame (Lumber+Panels)
Application
Shear Walls
Organization
University of Alberta
Material
Light Frame (Lumber+Panels)
Application
Shear Walls
Topic
Design and Systems
Seismic
Energy Performance
Keywords
Shear Walls
Insulated Sheathing
Racking Resistance
Research Status
In Progress
Notes
Project contact is Y.H. Chui at the University of Alberta
Summary
Wood shear wall systems with insulated sheathing are commonly implemented to meet a higher standard of building energy efficiency. Adding a layer of continuous thermal insulation exterior to the cavity insulation, insulated sheathing, to reduce thermal bridging is getting more popular in practice. The impact of the intermediated insulation on racking performance of shear walls has recently been investigated by experimental studies. The test data provides better understanding on the influence of various construction configurations. Nevertheless, there is a need to provide an alternative approach which enables engineers to calculate the design capacities of shear walls with insulated sheathing. In this project, the available analytical models and approaches for determining shear resistances of shear walls are reviewed and compared. A new modified analytical model will be developed based on comparisons and the test results.
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Study of Massive Timber Walls based on NLT and Post Laminated LVL

https://research.thinkwood.com/en/permalink/catalogue1585
Year of Publication
2018
Topic
Connections
Mechanical Properties
Material
LVL (Laminated Veneer Lumber)
NLT (Nail-Laminated Timber)
Application
Shear Walls
Author
Zhang, Chao
Lee, George
Lam, Frank
Organization
University of British Columbia
Year of Publication
2018
Format
Report
Material
LVL (Laminated Veneer Lumber)
NLT (Nail-Laminated Timber)
Application
Shear Walls
Topic
Connections
Mechanical Properties
Keywords
Shear Tests
Glue Lines
Lateral Loading
Sheathing
Load Carrying Capacity
Stiffness
Energy Dissipation
Shear Strength
Research Status
Complete
Summary
Currently the massive timber shear walls are mainly made from Cross Laminated Timber (CLT), which possesses a high in-plane shear strength and rigidity. But only part of its elements (mainly the vertically aligned laminae) are engaged in carrying the vertical load and that could be a limitation when designing taller timber structures or wherever higher vertical load is present. This project studied alternative solutions to massive timber shear wall system, based on Nailed Laminated Timber (NLT) and post laminated LVL (Laminated Veneer Lumber). The test was conducted on three levels: shear test on glue/nail line, bending-shear test on a small element, and full size wall test under lateral loading. The former two tests investigated the properties of basic elements in NLT and post laminated LVL. The results were used to design and predict the performance of full size shear walls. The NLT walls were tested under two conditions: without sheathing and with plywood sheathing. The wall without sheathing had the lowest load-carrying capacity and lowest stiffness. Adding plywood sheathing significantly increased its strength and stiffness. The failure in the wall with sheathing was at the sheathing connections, in the forms of nail withdrawal, nail head pull through, and nail breakage. The NLT wall with sheathing had a peak load up to 60% higher than the comparable light wood frame wall, also with a higher stiffness and better ductility. NLT shear walls have an internal energy dissipating capacity which CLT and post laminated LVL walls lack. The post laminated LVL walls behaved as a rigid plate under lateral loading, with little internal deformation. The failure occurred at the holdowns not within the wall. The size effect of its shear strength was studied and an equation was developed to calculate the shear strength of a large size wall plate. Both products have efficient vertical load bearing mechanism by arranging all elements in the vertical direction. They may serve as alternative to light wood frame walls or CLT walls. Some guidelines for the application and design of NLT shear walls and post laminated LVL shear walls were proposed.
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Free
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Wetting and Drying Performance and On-site Moisture Protection of Nail-Laminated Timber Assemblies

https://research.thinkwood.com/en/permalink/catalogue1871
Year of Publication
2016
Topic
Moisture
Material
NLT (Nail-Laminated Timber)
CLT (Cross-Laminated Timber)
Application
Walls
Wood Building Systems
Author
Wang, Jieying
Organization
FPInnovations
Publisher
BC Housing Research Centre
Year of Publication
2016
Format
Report
Material
NLT (Nail-Laminated Timber)
CLT (Cross-Laminated Timber)
Application
Walls
Wood Building Systems
Topic
Moisture
Keywords
Wetting
Drying
Sheathing
Moisture Protection
Space Heating
Research Status
Complete
Summary
In recent years, nail-laminated timber has been increasingly used in wood construction, including both heavy timber non-residential buildings (for floors or roofs) and light wood-frame residential buildings (such as elevator shafts). However, such built-up assemblies, tend to have high wetting and low drying potential and are susceptible to moisture-related issues during the construction. This study evaluates moisture protection by the sheathing or membrane for nail-laminated timber assemblies during on-site construction in British Columbia. Severe wetting will lead to elevated moisture content. Therefore, the best practice when working with nail-laminated timber is to avoid wetting.
Online Access
Free
Resource Link
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