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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
Country of Publication
Austria
Format
Conference Paper
Material
CLT (Cross-Laminated Timber)
Topic
Market and Adoption
Keywords
Market
North America
Building Development
Research
Language
English
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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Comparative Energy Consumption Study on Tall Cross Laminated Timber Buildings for U.S. Climates

https://research.thinkwood.com/en/permalink/catalogue1636
Year of Publication
2016
Topic
Energy Performance
Material
CLT (Cross-Laminated Timber)
Application
Wood Building Systems
Author
Pei, Shiling
Khavari, Ali
Tabares-Velasco, Paulo
Zhao, Shichun
Year of Publication
2016
Country of Publication
Austria
Format
Conference Paper
Material
CLT (Cross-Laminated Timber)
Application
Wood Building Systems
Topic
Energy Performance
Keywords
US
Energy Efficiency
Internal Loads
Climate
Language
English
Conference
World Conference on Timber Engineering
Research Status
Complete
Notes
August 22-25, 2016, Vienna, Austria p. 3134-3141
Summary
Tall building (higher than 8 stories) construction using Cross laminated timber (CLT) is a relatively new trend for urban developments around the world. In the U.S., there is great interest in utilizing the potential of this new construction material. By analyzing a ten-story condominium building model constructed using building energy simulation program EnergyPlus, the energy efficiency of this emerging building type was evaluated and compared with a light metal frame building system (currently viable construction type for this height based on the U.S. building code). A sensitivity analysis was also conducted to study the impact of different weather and internal load conditions on building energy performances. It was concluded that efficiency of CLT envelope is high for heating energy savings, but its energy performance efficiency can be greatly affected by other factors including weather, internal loading, and HVAC control.
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Cross-Laminated Timber for Seismic Regions: Progress and Challenges for Research and Implementation

https://research.thinkwood.com/en/permalink/catalogue162
Year of Publication
2014
Topic
Seismic
Material
CLT (Cross-Laminated Timber)
Application
Shear Walls
Author
Pei, Shiling
van de Lindt, John
Popovski, Marjan
Berman, Jeffrey
Dolan, Daniel
Ricles, James
Sause, Richard
Blomgren, Hans-Erik
Rammer, Douglas
Publisher
American Society of Civil Engineers
Year of Publication
2014
Country of Publication
United States
Format
Journal Article
Material
CLT (Cross-Laminated Timber)
Application
Shear Walls
Topic
Seismic
Keywords
Lateral Loads
Prefabrication
US
Language
English
Research Status
Complete
Series
Journal of Structural Engineering
Summary
Compared to light-frame wood shear walls, it is relatively difficult for panelized CLT shear walls to achieve similar levels of lateral deflection without paying special attention to design details, i.e., connections. A design lacking ductility or energy dissipating mechanism will result in high acceleration amplifications and excessive global overturning demands for multistory buildings, and even more so for tall wood buildings. Although a number of studies have been conducted on CLT shear walls and building assemblies since the 1990s, the wood design community’s understanding of the seismic behavior of panelized CLT systems is still in the learning phase, hence the impetus for this article and the tall CLT building workshop, which will be introduced herein. For example, there has been a recent trend in engineering to improve resiliency, which seeks to design a building system such that it can be restored to normal functionality sooner after an earthquake than previously possible, i.e., it is a resilient system. While various resilient lateral system concepts have been explored for concrete and steel construction, this concept has not yet been realized for multistory CLT systems. This forum article presents a review of past research developments on CLT as a lateral force-resisting system, the current trend toward design and construction of tall buildings with CLT worldwide, and attempts to summarize the societal needs and challenges in developing resilient CLT construction in regions of high seismicity in the United States.
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Cross-Laminated Timber Rocking Wall with Replaceable Fuses: Validation through Full-Scale Shake Table Testing

https://research.thinkwood.com/en/permalink/catalogue2027
Year of Publication
2018
Topic
Seismic
Design and Systems
Material
CLT (Cross-Laminated Timber)
Application
Walls

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
Country of Publication
Austria
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
Language
English
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
Country of Publication
Canada
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
Language
English
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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Development and Full-Scale Validation of Resilience-Based Seismic Design of Tall Wood Buildings: The NHERI Tallwood Project

https://research.thinkwood.com/en/permalink/catalogue1477
Year of Publication
2017
Topic
Design and Systems
Seismic
Material
CLT (Cross-Laminated Timber)
Application
Walls
Wood Building Systems
Author
Pei, Shiling
van de Lindt, John
Ricles, James
Sause, Richard
Berman, Jeffrey
Ryan, Keri
Dolan, Daniel
Buchanan, Andrew
Robinson, Thomas
McDonnell, Eric
Blomgren, Hans-Erik
Popovski, Marjan
Rammer, Douglas
Year of Publication
2017
Country of Publication
New Zealand
Format
Conference Paper
Material
CLT (Cross-Laminated Timber)
Application
Walls
Wood Building Systems
Topic
Design and Systems
Seismic
Keywords
Tall Wood
Post-Tensioned
Rocking Walls
Resilience-Based Seismic Design
Shaking Table Test
Language
English
Conference
New Zealand Society for Earthquake Engineering Conference
Research Status
Complete
Notes
April 27-29, 2017, Wellington, New Zealand
Summary
With global urbanization trends, the demands for tall residential and mixeduse buildings in the range of 8~20 stories are increasing. One new structural system in this height range are tall wood buildings which have been built in select locations around the world using a relatively new heavy timber structural material known as cross laminated timber (CLT). With its relatively light weight, there is consensus amongst the global wood seismic research and practitioner community that tall wood buildings have a substantial potential to become a key solution to building future seismically resilient cities. This paper introduces the NHERI Tallwood Project recentely funded by the U.S. National Science Fundation to develop and validate a seismic design methodology for tall wood buildings that incorporates high-performance structural and nonstructural systems and can quantitatively account for building resilience. This will be accomplished through a series of research tasks planned over a 4-year period. These tasks will include mechanistic modeling of tall wood buildings with several variants of post-tensioned rocking CLT wall systems, fragility modeling of structural and non-structural building components that affect resilience, fullscale biaxial testing of building sub-assembly systems, development of a resilience-based seismic design (RBSD) methodology, and finally a series of full-scale shaking table tests of a 10-story CLT building specimen to validate the proposed design. The project will deliver a new tall building type capable of transforming the urban building landscape by addressing urbanization demand while enhancing resilience and sustainability.
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Development of Seismic Performance Factors for Cross Laminated Timber: Phase 2

https://research.thinkwood.com/en/permalink/catalogue803
Topic
Seismic
Material
CLT (Cross-Laminated Timber)
Application
Wood Building Systems
Author
van de Lindt, John
Rammer, Douglas
Pei, Shiling
Organization
Forest Products Laboratory
Country of Publication
United States
Format
Report
Material
CLT (Cross-Laminated Timber)
Application
Wood Building Systems
Topic
Seismic
Keywords
Seismic Performance Factors
US
Research Status
In Progress
Summary
A collaborative project between the Forest Products Laboratory and Colorado State University to develop seismic performance factors for cross laminated timber is underway. The project requires application of the FEMA P-695 methodology, which is purposely robust and detailed and requires that the project team follow specific procedures. Failure to develop these seismic performance factors would severely limit the acceptance of the CLT building systems in the United States, underscoring the need for application of the FEMA P-695. The FEMA P-695 document, “Quantification of Building Seismic Performance Factors,” was published in 2009 and defines a number of steps, all of which will be taken to develop the seismic performance factors for seismic design of CLT buildings. The objectives of this research are (1) to develop seismic performance factors for CLT subject to a peer review panel process that includes an independent peer review committee report and (2) to have the resulting seismic performance factors recognized in ASCE 7 Minimum Design Loads for Buildings and Other Structures.
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Direct Displacement Design of Tall CLT Building with Deformable Diaphragms

https://research.thinkwood.com/en/permalink/catalogue1650
Year of Publication
2016
Topic
Design and Systems
Seismic
Material
CLT (Cross-Laminated Timber)
Application
Wood Building Systems
Author
Bolvardi, Vahab
Pei, Shiling
van de Lindt, John
Dolan, James
Year of Publication
2016
Country of Publication
Austria
Format
Conference Paper
Material
CLT (Cross-Laminated Timber)
Application
Wood Building Systems
Topic
Design and Systems
Seismic
Keywords
Inter-Story Isolation
Displacement-Based Design
Simulation
Language
English
Conference
World Conference on Timber Engineering
Research Status
Complete
Notes
August 22-25, 2016, Vienna, Austria p. 3506-3514
Summary
In order to cope with the speed of urbanization around the world especially in areas of high seismicity, researchers and engineers have always been investigating cost-effective building systems with high seismic performance. Cross Laminated Timber (CLT) is a wood based material that is suitable for tall building construction. However, the current CLT system is prone to connection damage in strong earthquakes due to the vast majority of the system ductility resides in connections. One solution is the concept of inter-story isolation to develop a potentially resilient system that can remain damage free during strong earthquakes. A generalized displacement-based design method was developed to design an inter-story isolation system for a tall wood building based on articulated damage expectations. A12-story CLT building with one isolation layer was used to illustrate the proposed design method. The building performance was validated through numerical simulation under different seismic hazard levels.
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Ductility Based Force Reduction Factors for Symmetrical Cross-Laminated Timber Structures

https://research.thinkwood.com/en/permalink/catalogue446
Year of Publication
2014
Topic
Mechanical Properties
Seismic
Material
CLT (Cross-Laminated Timber)
Application
Wood Building Systems
Walls
Author
Popovski, Marjan
Pei, Shiling
van de Lindt, John
Karacabeyli, Erol
Organization
European Association of Earthquake Engineering
Year of Publication
2014
Country of Publication
Canada
Format
Conference Paper
Material
CLT (Cross-Laminated Timber)
Application
Wood Building Systems
Walls
Topic
Mechanical Properties
Seismic
Keywords
Force Modification Factors
Ductility
National Building Code of Canada
Fasteners
Seismic Performance
Language
English
Conference
Second European Conference on Earthquake Engineering and Seismology
Research Status
Complete
Notes
August 25-29, 2014, Istanbul, Turkey
Summary
Cross-laminated timber (CLT) as a structural system has not been fully introduced in European or North American building codes. One of the most important issues for designers of CLT structures in earthquake prone regions when equivalent static design procedure is used, are the values for the force modification factors (R-factors) for this structural system. Consequently, the objective of this study was to derive suitable ductility-based force modification factors (Rd-factors) for seismic design of CLT buildings for the National Building Code of Canada (NBCC). For that purpose, the six-storey NEESWood Capstone wood-frame building was redesigned as a CLT structure and was used as a reference symmetrical structure for the analyses. The same floor plan was used to develop models for ten and fifteen storey buildings. Non-linear analytical models of the buildings designed with different Rd-factors were developed using the SAPWood computer program. CLT walls were modelled using the output from mechanics models developed in Matlab that were verified against CLT wall tests conducted at FPInnovations. Two design methodologies for determining the CLT wall design resistance (to include and exclude the influence of the hold-downs), were used. To study the effects of fastener behaviour on the R-factors, three different fasteners (16d nails, 4x70mm and 5x90mm screws) used to connect the CLT walls, were used in the analyses. Each of the 3-D building models was subjected to a series of 22 bi-axial input earthquake motions suggested in the FEMA P-695 procedure. Based on the results, the fragility curves were developed for the analysed buildings. Results showed that an Rd-factor of 2.0 is appropriate conservative estimate for the symmetrical CLT buildings studied, for the chosen level of seismic performance.
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25 records – page 1 of 3.