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An Overview of CLT Research and Implementation in North America

https://research.thinkwood.com/en/permalink/catalogue759
Year of Publication
2016
Topic
Market and Adoption
Material
CLT (Cross-Laminated Timber)
Author
Pei, Shiling
Rammer, Douglas
Popovski, Marjan
Williamson, Tom
Line, Philip
van de Lindt, John
Year of Publication
2016
Format
Conference Paper
Material
CLT (Cross-Laminated Timber)
Topic
Market and Adoption
Keywords
Market
North America
Building Development
Research
Conference
World Conference on Timber Engineering
Research Status
Complete
Notes
August 22-25, 2016, Vienna, Austria
Summary
Although not yet seen as common practice, building with cross laminated timber (CLT) is gaining momentum in North America. Behind the scenes of the widely publicized project initiatives such as the Wood Innovation Design Centre Building in Canada and the recent U.S. Tall Wood Building Competition, substantial research, engineering, and development has been completed or is underway to enable the adoption of this innovative building system. This paper presents a brief overview of the current status of CLT building development in North America, highlighting some recent U.S. and Canadian research efforts related to CLT system performance, and identifies future CLT research directions based on the needs of the North American market. The majority of the research summarized herein is from a recent CLT research workshop in Madison, Wisconsin, USA, organized by the USDA Forest Products Laboratory. The opportunity and need for coordination in CLT research and development among the global timber engineering community are also highlighted in the conclusions of this paper.
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Determination of Seismic Performance Factors for CLT Shear Wall Systems

https://research.thinkwood.com/en/permalink/catalogue770
Year of Publication
2016
Topic
Connections
Seismic
Material
CLT (Cross-Laminated Timber)
Application
Shear Walls
Author
Amini, M. Omar
van de Lindt, John
Rammer, Douglas
Pei, Shiling
Line, Philip
Popovski, Marjan
Year of Publication
2016
Format
Conference Paper
Material
CLT (Cross-Laminated Timber)
Application
Shear Walls
Topic
Connections
Seismic
Keywords
Angle Bracket
Cyclic Tests
US
Quasi-Static
Seismic Performance Factors
Conference
World Conference on Timber Engineering
Research Status
Complete
Notes
August 22-25, 2016, Vienna, Austria
Summary
This paper presents selected results of connector testing and wall testing which were part of a Forest Products Lab-funded project undertaken at Colorado State University in an effort to determine seismic performance factors for cross laminated timber (CLT) shear walls in the United States. Archetype development, which is required as part of the process, is also discussed. Connector tests were performed on generic angle brackets which were tested under shear and uplift and performed as expected with consistent nail withdrawal observed. Quasi-static cyclic tests were conducted on CLT shear walls to systematically investigate the effects of various parameters. Boundary constraints and gravity loading were both found to have a beneficial effect on the wall performance, i.e. higher strength and deformation capacity. Specific gravity also had a significant effect on wall behaviour while CLT thickness was less influential. Higher aspect ratio panels (4:1) demonstrated lower stiffness and substantially larger deformation capacity compared to moderate aspect ratio panels (2:1). However, based on the test results there is likely a lower bound of 2:1 for aspect ratio where it ceases to have any beneficial effect on wall behaviour. This is likely due to the transition from the dominant rocking behaviour to sliding behaviour.
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Developing Seismic Performance Factors for Cross Laminated Timber in the United States

https://research.thinkwood.com/en/permalink/catalogue124
Year of Publication
2015
Topic
Seismic
Mechanical Properties
Connections
Material
CLT (Cross-Laminated Timber)
Application
Walls
Author
van de Lindt, John
Amini, M. Omar
Rammer, Douglas
Line, Philip
Pei, Shiling
Popovski, Marjan
Organization
Canadian Association for Earthquake Engineering
Year of Publication
2015
Format
Conference Paper
Material
CLT (Cross-Laminated Timber)
Application
Walls
Topic
Seismic
Mechanical Properties
Connections
Keywords
Angle Bracket
Shear Test
Strength
Stiffness
Uplift Test
US
Conference
The 11th Canadian Conference on Earthquake Engineering
Research Status
Complete
Notes
July 21-24, 2015, Victoria, BC, Canada
Summary
This paper presents recent progress in the development of seismic performance factors for cross-laminated timber (CLT) systems in the United States. A brief overview of some of other systematic studies conducted in Europe, North America, and Japan is also provided. The FEMA P695 methodology is briefly described and selected results from connector testing and CLT wall testing are discussed. Shear and uplift tests were performed on generic angle brackets to quantify their behavior. CLT walls with these connectors were then tested investigate the influence of various parameters on wall component performance. The influential factors considered include boundary condition, gravity loading, CLT grade, panel thickness, and panel aspect ratio (height:length). Results indicate that boundary condition and gravity loading have beneficial effect on strength and stiffness of the CLT panels. CLT grade is an important parameter while CLT panel thickness only has a minimal influence on wall behavior. Higher aspect ratio (4:1) panels demonstrated less stiffness but considerably more ductility than the panels with lower aspect ratio (2:1). This paper also provides details on some ongoing efforts including additional tests planned, index buildings from which P-695 archetypes will be extracted, and nonlinear modeling for this project.
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Experimental Seismic Behavior of a Two-Story CLT Platform Building: Shake Table Testing Results

https://research.thinkwood.com/en/permalink/catalogue2052
Year of Publication
2018
Topic
Seismic
Mechanical Properties
Material
CLT (Cross-Laminated Timber)
Application
Wood Building Systems
Author
van de Lindt, John
Amini, Omar
Furley, Jace
Pei, Shiling
Tamagnone, Gabriele
Barbosa, André
Line, Philip
Rammer, Douglas
Fragiacomo, Massimo
Organization
Colorado State University
University of Trieste
Oregon State University
Amarican Wood Council
Forest Products Laboratory
University of L'Aquila
Year of Publication
2018
Format
Conference Paper
Material
CLT (Cross-Laminated Timber)
Application
Wood Building Systems
Topic
Seismic
Mechanical Properties
Keywords
Shake Table Tests
Full Scale
Service Level Earthquake
Design Base Earthquake
Maximum Considered Earthquake
Seismic Force Resisting System
Conference
World Conference on Timber Engineering
Research Status
Complete
Summary
With the increased usage of Cross Laminated Timber (CLT) in the United States, research efforts have been focused on demonstrating CLT as an effective Seismic Force Resisting System (SFRS). Presented in this paper are the findings of full-scale shake table tests of a two-story 223 m2 (2400 ft2) building with two sets of CLT shear walls on the first and second story. The testing consisted of three phases, each with a unique wall configuration, but only the first phase is presented herein, which consisted of a shear wall with 4:1 aspect ratio CLT panels. The structure was subjected to ground motions scaled to intensities that correspond to a Service Level Earthquake (SLE), Design Base Earthquake (DBE), and Maximum Considered Earthquake (MCE) respectively. In all phases and motions the structure performed well and was in accordance with FEMA collapse prevention requirements for each motion intensity.
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Free
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Influence of Varying Strength, from Story to Story, on Modeled Seismic Response of Wood-Frame Shear Wall Structures

https://research.thinkwood.com/en/permalink/catalogue2075
Year of Publication
2018
Topic
Seismic
Material
Light Frame (Lumber+Panels)
Application
Walls
Shear Walls
Wood Building Systems
Author
Perry, Logan
Line, Philip
Charney, Finley
Organization
Virginia Tech
Year of Publication
2018
Format
Conference Paper
Material
Light Frame (Lumber+Panels)
Application
Walls
Shear Walls
Wood Building Systems
Topic
Seismic
Keywords
Hysteretic Model
Seismic Analysis
Multi-Story
Conference
World Conference on Timber Engineering
Research Status
Complete
Summary
This paper presents a numerical study of the influence of varying story strength on the seismic performance of multi-story wood-frame shear wall buildings. In the prior FEMA P695 studies of these buildings, the non-simulated collapse limit-state was exceeded primarily in the first story [6]. This observation raised interest in quantifying the influence of varying strength from story to story on seismic response. In this study, four different distributions of strength are used as bounding cases. The Parabolic strength distribution (1) is based upon the ELF method in ASCE 7 and assigns lateral forces to each level based on weight and story height. The Triangular strength distribution (2) is based upon the simplified procedure in ASCE 7 and distributes lateral forces based on the seismic weight at each level. The Constant strength distribution (3) assumes the same shear wall design was used on all levels. The Baseline strength distribution (4) is from actual designs provided in the FEMA P695 wood-frame example and represents the practical implementation of the ELF method for designed shear walls. The FEMA P695 methodology, which quantifies seismic performance via adjusted collapse margin ratios, is employed in this study. The analytical models include P-Delta effects and utilize the 10-parameter CASHEW hysteresis model. Based on the analysis of a subset of index models from the FEMA P695 wood-frame example, it is observed that the Parabolic strength distribution, which facilitates dissipation of energy along the entire height of the building, has larger adjusted collapse margin ratios (lower collapse risk) than other strength distributions studied and reduces occurrence of concentrated inelastic deformations in a single story from the onset of an applied lateral force.
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Lateral Testing of Glued Laminated Timber Tudor Arch

https://research.thinkwood.com/en/permalink/catalogue1722
Year of Publication
2016
Topic
Seismic
Mechanical Properties
Material
Glulam (Glue-Laminated Timber)
Application
Arches
Author
Rammer, Douglas
Line, Philip
Year of Publication
2016
Format
Conference Paper
Material
Glulam (Glue-Laminated Timber)
Application
Arches
Topic
Seismic
Mechanical Properties
Keywords
Full Scale
Lateral Load
Damping
Deformation
Failure Modes
Conference
World Conference on Timber Engineering
Research Status
Complete
Notes
August 22-25, 2016, Vienna, Austria p. 4638-4646
Summary
Glued laminated timber Tudor arches have been in wide use in the United States since the 1930s, but detailed knowledge related to seismic design in modern U.S. building codes is lacking. FEMA P-695 (P-695) is a methodology to determine seismic performance factors for a seismic force resisting system. A limited P-695 study for glued laminated timber arch structures highlighted the lack of lateral load testing; therefore, critical modelling information was not available and assumptions based on available research were used. In this study, full-scale lateral load testing of the glued laminated timber arch is used to fill in gaps in test-based information and assess the following characteristics: damping, deformation behaviour, and failure modes.
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Free
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Seismic Analysis of Three-Hinge Glulam Tudor Arches Using the FEMA P-695 Methodology

https://research.thinkwood.com/en/permalink/catalogue693
Year of Publication
2014
Topic
Seismic
Material
Glulam (Glue-Laminated Timber)
Application
Arches
Author
Charney, Finley
Eberle, Jonathan
Line, Philip
Kochkin, Vladimir
Year of Publication
2014
Format
Conference Paper
Material
Glulam (Glue-Laminated Timber)
Application
Arches
Topic
Seismic
Keywords
Maximum Considered Earthquake
Seismic Response Modification Factor
Conference
World Conference on Timber Engineering
Research Status
Complete
Notes
August 10-14, 2014, Quebec City, Canada
Summary
This paper discusses the determination of the ASCE 7 seismic response modification factor R for three-hinge glulam Tudor arches. In an attempt to meet this objective, a limited application of the methods and procedures outlined in FEMA P-695 were used to assess the performance of a variety of arch designs. Computational models were created using finite elements within OpenSees to accurately depict the behaviour of the arch. When the crown connections were redesigned using load combinations incorporating over-strength, all of the light gravity load designs systems were successfully able to demonstrate a probability of collapse of less than ten percent when subjected to Maximum Considered Earthquake (MCE) level of ground shaking. Systems designed for heavy gravity did not pass; however, a variety of sidestudies on the influence of inelastic behaviour in the base connections, and varied levels of damping indicate that acceptance criteria of FEMA P-695 may be met through refined modeling assumptions based on results of testing.
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Free
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Systematic Experimental Investigation to Support the Development of Seismic Performance Factors for Cross Laminated Timber Shear Wall Systems

https://research.thinkwood.com/en/permalink/catalogue1281
Year of Publication
2018
Topic
Seismic
Material
CLT (Cross-Laminated Timber)
Application
Shear Walls
Author
Amini, Omar
van de Lindt, John
Rammer, Douglas
Pei, Shiling
Line, Philip
Popovski, Marjan
Publisher
ScienceDirect
Year of Publication
2018
Format
Journal Article
Material
CLT (Cross-Laminated Timber)
Application
Shear Walls
Topic
Seismic
Keywords
Quasi-Static
Cyclic Tests
Stiffness
Strength
Deformation
Aspect Ratios
Thickness
Joints
Research Status
Complete
Series
Engineering Structures
Summary
In the US, codified seismic design procedure requires the use of seismic performance factors which are currently not available for CLT shear wall systems. The study presented herein focuses on the determination of seismic design factors for CLT shear walls in platform type construction using the FEMA P-695 process. Results from the study will be proposed for implementation in the seismic design codes in the US. The project approach is outlined and selected results of full-scale shear wall testing are presented and discussed. Archetype development, which is required as part of the FEMA P-695 process, is briefly explained with an example. Quasi-static cyclic tests were conducted on CLT shear walls to systematically investigate the effects of various parameters. The key aspect of these tests is that they systematically investigate each potential modelling attribute that is judged within the FEMA P-695 uncertainty quantification process. Boundary constraints and gravity loading were both found to have a beneficial effect on the wall performance, i.e. higher strength and deformation capacity. Higher aspect ratio panels (4:1) demonstrated lower stiffness and substantially larger deformation capacity compared to moderate aspect ratio panels (2:1). However, based on the test results there is likely a lower bound for aspect ratio (at 2:1) where it ceases to benefit deformation capacity of the wall. This is due to the transition of the wall behaviour from rocking to sliding. Phenomenological models were used in modelling CLT shear walls. Archetype selection and analysis procedure was demonstrated and nonlinear time history analysis was conducted using different wall configurations.
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Free
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8 records – page 1 of 1.