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24 records – page 1 of 3.

Seismic Assessment of a Three-Story Wood Building with an Integrated CLT-Lightframe System using RTHS

https://research.thinkwood.com/en/permalink/catalogue1293
Year of Publication
2018
Topic
Mechanical Properties
Seismic
Material
CLT (Cross-Laminated Timber)
Light Frame (Lumber+Panels)
Application
Shear Walls
Author
Nguyen, Tu
Dao, Thang
Aaleti, Sriram
van de Lindt, John
Fridley, Kenneth
Publisher
ScienceDirect
Year of Publication
2018
Country of Publication
Netherlands
Format
Journal Article
Material
CLT (Cross-Laminated Timber)
Light Frame (Lumber+Panels)
Application
Shear Walls
Topic
Mechanical Properties
Seismic
Keywords
Post-Tensioned
Real Time Hybrid Simulation
Language
English
Research Status
Complete
Series
Engineering Structures
Summary
This paper presents the results of an experimental study whose objective was to investigate the behavior of a hybrid wood shear-wall system defined herein as a combination of traditional light-frame wood shear walls with post-tensioned rocking Cross-Laminated Timber (CLT) panels. The post-tensioned CLT panels in the hybrid system offer both vertical and lateral load resistance and self-centering capacities. The traditional Light-Frame Wood Systems (LiFS) provide additional lateral load resistance along with a large amount of energy dissipation through the friction of nail connections. Thus, a combination of these two types of structures, in which traditional light-frame wood shearwalls are utilized as structural partition walls, may provide an excellent structural solution for mid-rise to tall wood buildings for apartments/condos, where there is a need for resisting large lateral and vertical loads as well as structural stability. In this study, a real-time hybrid testing algorithm using a combination of time-delay updating and Newmark-Beta feed forward to reduce the undesirable effects of time delay was introduced. The top two-stories of a three-story building were modeled as a numerical substructure with the first story as the experimental CLT-LiFS substructure. The experimental results of the hybrid wall are presented and discussed in this paper.
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Seismic Design of Cross-Laminated Timber Buildings

https://research.thinkwood.com/en/permalink/catalogue1971
Year of Publication
2018
Topic
Seismic
Design and Systems
Material
CLT (Cross-Laminated Timber)
Application
Wood Building Systems
Author
Tannert, Thomas
Follesa, Maurizio
Fragiacomo, Massimo
González Soto, Paulina
Isoda, Hiroshi
Moroder, Daniel
Xiong, Haibei
van de Lindt, John
Publisher
Society of Wood Science and Technology
Year of Publication
2018
Country of Publication
United States
Format
Journal Article
Material
CLT (Cross-Laminated Timber)
Application
Wood Building Systems
Topic
Seismic
Design and Systems
Keywords
Seismicity
Design Standards
Platform-Type Construction
Ductility
Connections
Language
English
Research Status
Complete
Series
Wood and Fiber Science
Summary
The increasing interest in cross-laminated timber (CLT) construction has resulted in multiple international research projects and publications covering the manufacturing and performance of CLT. Multiple regions and countries have adopted provisions for CLT into their engineering design standards and building regulations. Designing and building CLT structures, also in earthquake-prone regions is no longer a domain for early adopters, but is becoming a part of regular timber engineering practice...
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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
Country of Publication
Netherlands
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
Language
English
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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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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Hybrid System of Unbonded Post-Tensioned CLT Panels and Light-Frame Wood Shear Walls

https://research.thinkwood.com/en/permalink/catalogue757
Year of Publication
2017
Topic
Design and Systems
Mechanical Properties
Seismic
Material
CLT (Cross-Laminated Timber)
Light Frame (Lumber+Panels)
Application
Shear Walls
Author
Ho, Tu Xuan
Dao, Thang
Aaleti, Sriram
van de Lindt, John
Rammer, Douglas
Publisher
American Society of Civil Engineers
Year of Publication
2017
Country of Publication
United States
Format
Journal Article
Material
CLT (Cross-Laminated Timber)
Light Frame (Lumber+Panels)
Application
Shear Walls
Topic
Design and Systems
Mechanical Properties
Seismic
Keywords
Post-Tensioned
Cyclic Loadings
Dynamic Analysis
Numerical model
Language
English
Research Status
Complete
Series
Journal of Structural Engineering
Summary
Cross-laminated timber (CLT) is a relatively new type of massive timber system that has shown to possess excellent mechanical properties and structural behavior in building construction. When post-tensioned with high-strength tendons, CLT panels perform well under cyclic loadings because of two key characteristics: their rocking behavior and self-centering capacity. Although post-tensioned rocking CLT panels can carry heavy gravity loads, resist lateral loads, and self-center after a seismic event, they are heavy and form a pinched hysteresis, thereby limiting energy dissipation. Conversely, conventional light-frame wood shear walls (LiFS) provide a large amount of energy dissipation from fastener slip and, as their name implies, are lightweight, thereby reducing inertial forces during earthquakes. The combination of these different lateral behaviors can help improve the performance of buildings during strong ground shaking, but issues of deformation compatibility exist. This study presents the results of a numerical study to examine the behavior of post-tensioned CLT walls under cyclic loadings. A well-known 10-parameter model was applied to simulate the performance of a CLT-LiFS hybrid system. The posttensioned CLT wall model was designed on the basis of a modified monolithic beam analogy that was originally developed for precast concrete-jointed ductile connections. Several tests on post-tensioned CLT panels and hybrid walls were implemented at the Large Scale Structural Lab at the University of Alabama to validate the numerical model, and the results showed very good agreement with the numerical model. Finally, incremental dynamic analysis on system level models was compared with conventional light-frame wood system models.
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Mass Timber Rocking Panel Retrofit of a Four-Story Soft-Story Building with Full-Scale Shake Table Validation

https://research.thinkwood.com/en/permalink/catalogue833
Year of Publication
2017
Topic
Seismic
Material
CLT (Cross-Laminated Timber)
Light Frame (Lumber+Panels)
Application
Wood Building Systems
Author
Bahmani, Pouria
van de Lindt, John
Iqbal, Asif
Rammer, Douglas
Publisher
MDPI
Year of Publication
2017
Country of Publication
United States
Format
Journal Article
Material
CLT (Cross-Laminated Timber)
Light Frame (Lumber+Panels)
Application
Wood Building Systems
Topic
Seismic
Keywords
FEMA
Full Scale
Retrofit
Seismic
Shake Table Test
Soft-Story
US
Language
English
Research Status
Complete
Series
Buildings
Summary
Soft-story wood-frame buildings have been recognized as a disaster preparedness problem for decades. There are tens of thousands of these multi-family three- and four-story structures throughout California and other cities in the United States. The majority were constructed between 1920 and 1970, with many being prevalent in the San Francisco Bay Area in California. The NEES-Soft project was a five-university multi-industry effort that culminated in a series of full-scale soft-story wood-frame building tests to validate retrofit philosophies proposed by (1) the Federal Emergency Management Agency (FEMA) P-807 guidelines and (2) a performance-based seismic retrofit (PBSR) approach developed within the project. Four different retrofit designs were developed and validated at full-scale, each with specified performance objectives, which were typically not the same. This paper focuses on the retrofit design using cross laminated timber (CLT) rocking panels and presents the experimental results of the full-scale shake table test of a four-story 370 m2 (4000 ft2) soft-story test building with that FEMA P-807 focused retrofit in place. The building was subjected to the 1989 Loma Prieta and 1992 Cape Mendocino ground motions scaled to 5% damped spectral accelerations ranging from 0.2 to 0.9 g.
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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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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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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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Experimental Investigation of Self-Centering Cross Laminated Timber Walls

https://research.thinkwood.com/en/permalink/catalogue1654
Year of Publication
2016
Topic
Seismic
Mechanical Properties
Material
CLT (Cross-Laminated Timber)
Application
Walls
Author
Ganey, Ryan
Berman, Jeffrey
Yao, Lihong
Dolan, Daniel
Akbas, Tugce
Loftus, Sara
Sause, Richard
Ricles, James
Pei, Shiling
van de Lindt, John
Blomgren, Hans-Erik
Year of Publication
2016
Country of Publication
Austria
Format
Conference Paper
Material
CLT (Cross-Laminated Timber)
Application
Walls
Topic
Seismic
Mechanical Properties
Keywords
Lateral Load Resisting System
Post-Tensioning
U-Shaped Flexural Plates
Limit States
Self-Centering
Strength
Stiffness
Interstory Drifts
Language
English
Conference
World Conference on Timber Engineering
Research Status
Complete
Notes
August 22-25, 2016, Vienna, Austria p. 3547-3554
Summary
This paper describes experiments conducted to develop a resilient lateral force resisting wall system that combines cross-laminated timber (CLT) panels with vertical post-tensioning (PT) to provide post-event re-centering. Supplemental mild steel U-shaped flexural plate devices (UFPs) are intended to yield under cyclic loading while the PT and CLT components remain undamaged until large inter-story drifts are experienced by the wall. The experiments were designed to explore various limit states for self-centering CLT (SC-CLT) walls, including their dependence on design variables and their impact on performance, and to investigate strength and stiffness degradation at large interstory drifts. It was found that the SC-CLT walls were able to re-center even after large drift cycles and the crushing of the CLT material was the governing limit sate for most specimens. A hierarchy of desirable limit states was identified consisting of UFP yielding, CLT splitting, PT yielding, and CLT crushing.
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24 records – page 1 of 3.