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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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Nail-Laminated Timber U.S. Design and Construction Guide

https://research.thinkwood.com/en/permalink/catalogue834
Edition
1.0
Year of Publication
2017
Topic
Acoustics and Vibration
Connections
Design and Systems
Fire
General Information
Moisture
Seismic
Site Construction Management
Material
NLT (Nail-Laminated Timber)
Application
Floors
Roofs
Editor
Holt, Rebecca Luthi, Tanya Dickof, Carla
Edition
1.0
Publisher
Binational Softwood Lumber Council
Year of Publication
2017
Country of Publication
United States
Format
Book/Guide
Material
NLT (Nail-Laminated Timber)
Application
Floors
Roofs
Topic
Acoustics and Vibration
Connections
Design and Systems
Fire
General Information
Moisture
Seismic
Site Construction Management
Language
English
Research Status
Complete
Summary
This Design and Construction Guide (the Guide) provides the U.S. design and construction community with guidance to ensure safe, predictable, and economical use of NLT. It is intended to offer practical strategies, advice, and guidance, transferring knowledge and lessons learned from NLT project experience. This Guide focuses on design and construction considerations for floor and roof systems pertaining to U.S. construction practice and standards. While NLT is being used for vertical elements for walls, stair shafts, and elevator shafts, this Guide provides the greatest depth of direction for more common horizontal applications. The information included here is supplemental to wood design and construction best practices and is specific to the application of NLT. Built examples are included to illustrate real application and visual reference as much as possible.
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Free
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The Case for Tall Wood Buildings

https://research.thinkwood.com/en/permalink/catalogue835
Edition
Second
Year of Publication
2017
Topic
General Information
Cost
Environmental Impact
Design and Systems
Material
CLT (Cross-Laminated Timber)
LSL (Laminated Strand Lumber)
LVL (Laminated Veneer Lumber)
Application
Wood Building Systems
Organization
Michael Green Architecture
Edition
Second
Year of Publication
2017
Country of Publication
Canada
Format
Book/Guide
Material
CLT (Cross-Laminated Timber)
LSL (Laminated Strand Lumber)
LVL (Laminated Veneer Lumber)
Application
Wood Building Systems
Topic
General Information
Cost
Environmental Impact
Design and Systems
Keywords
FFTT
Tall Wood
Language
English
Research Status
Complete
Summary
The report describes a new structural system in wood that is the first significant challenger to concrete and steel structures since their inception in tall building design more than a century ago. The introduction of these ideas is fundamentally driven by the need to find safe, carbon-neutral and sustainable alternatives to the incumbent structural materials of the urban world. The market for these ideas is quite simply enormous. The proposed solutions have significant capacity to revolutionize the building industry to address the major challenges of climate change, urbanization, sustainable development and world housing needs.
Online Access
Free
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Structural Analysis of In-Plane Loaded CLT Beams

https://research.thinkwood.com/en/permalink/catalogue1213
Year of Publication
2017
Topic
Mechanical Properties
Material
CLT (Cross-Laminated Timber)
Application
Beams
Author
Jelec, Mario
Strukar, Kristina
Rajcic, Vlatka
Organization
University of Osijek
Year of Publication
2017
Country of Publication
Croatia
Format
Journal Article
Material
CLT (Cross-Laminated Timber)
Application
Beams
Topic
Mechanical Properties
Keywords
In-Plane Loading
Shear Stress
Failure Modes
FE Analysis
Eurocode 5
Language
English
Research Status
Complete
Series
e-GFOS
ISSN
1847-8948
Summary
Cross laminated timber (CLT) is a versatile engineered timber product that is increasingly well-known and of global interest in several applications such as full size plane or linear timber elements. The aim of this study involves investigating the performance of CLT beams loaded in-plane by considering bending and shear stress analysis with a special emphasis on the in-plane shear behavior including the complex internal structure of CLT. Numerical analysis based on 3D-FE models was used and compared with two existing analytical approaches, namely representative volume sub element (method I) and composite beam theory (method II). The separate verification of bending and shear stresses including tree different shear failure modes was performed, and a good agreement was obtained. The main difference between the results relates to shear failure mode in the crossing areas between the orthogonally bonded lamellas in which the distribution of shear stresses tzx over the crossing areas per height of the CLT beam is not in accordance with the analytical assumptions. The presented analyses constitute the first attempt to contribute to the on-going review process of Eurocode 5 with respect to CLT beams loaded-in plane. Currently, regulations on designing these types of beams do not exist, and thus experimental and numerical investigations are planned in the future.
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Evaluation of Bending Performance for Cross Laminated Timber (CLT) Made Out of Poplar (Populus Alba)

https://research.thinkwood.com/en/permalink/catalogue1218
Year of Publication
2017
Topic
Mechanical Properties
Material
CLT (Cross-Laminated Timber)
Application
Floors
Author
Haftkhani, Akbar
Layeghi, Mohammad
Ebrahimi, Ghanbar
Pourtahmasi, Kambiz
Publisher
Iranian Scientific Association of Wood and Paper Industries
Year of Publication
2017
Country of Publication
Islamic Republic of Iran
Format
Journal Article
Material
CLT (Cross-Laminated Timber)
Application
Floors
Topic
Mechanical Properties
Keywords
Bending Strength
Poplar
Modulus of Rupture
Modulus of Elasticity
Polyurethane
Language
Persian
Research Status
Complete
Series
Iranian Journal of Wood and Paper Industries
Summary
Bending strength is a critical property of cross laminated timber (CLT) in structural applications, especially in floor of multi-story buildings. Therefore, this study was targeted to evaluate bending strength of CLT made out of poplar (populous alba). Polyurethane adhesive was used for constructing of CLT (300 g/m2). The thickness of planks was used in this study was 16 mm. The results have indicated that modulus of rupture (MOR) and modulus of elasticity (MOE) of CLT with 45o alternating transverse layer were increased 14 and 15%, respectively in comparison with 90o layers. Also, modulus of rupture (MOR) and modulus of elasticity (MOE) of CLT consist of layers with 4cm in width were increased 14 and 5%, respectively in comparison with layers 9cm in width. The results concluded that by layers with lower width, and also 45o alternating layer configuration could be constructed CLT from fast growing trees such as poplar with a considerable bending strength.
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Lateral-Load Resistance of Cross-Laminated Timber Shear Walls

https://research.thinkwood.com/en/permalink/catalogue1238
Year of Publication
2017
Topic
Connections
Mechanical Properties
Material
CLT (Cross-Laminated Timber)
Application
Shear Walls
Author
Reynolds, Thomas
Foster, Robert
Bregulla, Julie
Chang, Wen-Shao
Harris, Richard
Ramage, Michael
Publisher
American Society of Civil Engineers
Year of Publication
2017
Country of Publication
United States
Format
Journal Article
Material
CLT (Cross-Laminated Timber)
Application
Shear Walls
Topic
Connections
Mechanical Properties
Keywords
Vertical Load
Lateral Load
Pullout Tests
Steel Connectors
Offset-Yield Criterion
Language
English
Research Status
Complete
Series
Journal of Structural Engineering
Summary
Cross-laminated timber shear wall systems are used as a lateral load resisting system in multistory timber buildings. Walls at each level typically bear directly on the floor panels below and are connected by nailed steel brackets. Design guidance for lateral load resistance of such systems is not well established and design approaches vary among practitioners. Two cross-laminated two-story timber shear wall systems are tested under vertical and lateral load, along with pull-out tests on individual steel connectors. Comprehensive kinematic behavior is obtained from a combination of discrete transducers and continuous field displacements along the base of the walls, obtained by digital image correlation, giving a measure of the length of wall in contact with the floor below. Existing design approaches are evaluated. A new offset-yield criterion based on acceptable permanent deformations is proposed. A lower bound plastic distribution of stresses, reflecting yielding of all connectors in tension and cross-grain crushing of the floor panel, is found to most accurately reflect the observed behavior.
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Free
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Seismic Base Shear Modification Factors for Timber-Steel Hybrid Structure: Collapse Risk Assessment Approach

https://research.thinkwood.com/en/permalink/catalogue1241
Year of Publication
2017
Topic
Seismic
Mechanical Properties
Material
CLT (Cross-Laminated Timber)
Application
Hybrid Building Systems
Author
Bezabeh, Matiyas
Tesfamariam, Solomon
Popovski, Marjan
Goda, Katsuichiro
Stiemer, Siegfried
Publisher
American Society of Civil Engineers
Year of Publication
2017
Country of Publication
United States
Format
Journal Article
Material
CLT (Cross-Laminated Timber)
Application
Hybrid Building Systems
Topic
Seismic
Mechanical Properties
Keywords
Canada
Timber-Steel Hybrid
Overstrength
Force Modification Factors
Collapse Risk Assessment Approach
Adjusted Collapse Margin Ratios
Language
English
Research Status
Complete
Series
Journal of Structural Engineering
Summary
In this paper, to supplement the Canadian building code for a timber-steel hybrid structure, over-strength, and ductility-related force modification factors are developed and validated using a collapse risk assessment approach. The hybrid structure incorporates cross-laminated timber (CLT) infill walls within steel moment resisting frames. Following the FEMA P695 procedure, archetype buildings of 3-story, 6-story, and 9-story height with middle bay infilled with CLT were developed. Subsequently, a nonlinear static pushover analysis was performed to quantify the actual over-strength factors of the hybrid archetype buildings. To check the FEMA P695 acceptable collapse probabilities and adjusted collapse margin ratios (ACMRs), incremental dynamic analysis was carried out using 60 ground motion records that were selected to regional seismic hazard characteristics in southwestern British Columbia, Canada. Considering the total system uncertainty, comparison of the calculated ACMRs with the FEMA P695 requirement indicates the acceptability of the proposed over-strength and ductility factors
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Investigation into the Failure of a Long-Span Glued Laminated Beam

https://research.thinkwood.com/en/permalink/catalogue1251
Year of Publication
2017
Topic
Mechanical Properties
Material
Glulam (Glue-Laminated Timber)
Application
Roofs
Author
Shuck, Andrew
Porto, Jason
Sasaki, Kent
Organization
Structures Congress
Publisher
American Society of Civil Engineers
Year of Publication
2017
Country of Publication
United States
Format
Conference Paper
Material
Glulam (Glue-Laminated Timber)
Application
Roofs
Topic
Mechanical Properties
Keywords
Failure
Language
English
Conference
Structures Congress 2017
Research Status
Complete
Notes
April 6–8, 2017, Denver, Colorado
Summary
The failure of wood roof members in older buildings is a fairly common occurrence compared to systems built of steel or concrete. The slow-working detrimental effect of sustained loading at relatively high stress levels (i.e., “creep rupture” or “cumulative damage”) is typically viewed as the predominant failure mechanism, but this is not always the case. The following describes a case study of a glulam beam that failed for other reasons. The subject glulam beam that failed absent a significant atypical loading event was one of many in the roof structure of a large building. Each glulam beam was about five feet deep and 100 feet long. At the time of failure, the subject glulam beam was 41 years old. Through the course of the investigation, significant research was performed into multiple aspects of glulam beam behavior, including revisions to design stresses over time, fabrication technology, and time-dependent properties. Detailed field observations were performed to document the failed beam, the surrounding elements, and the assemblies supported by the roof framing. The cause of the failure was ultimately found to be a fabrication error.
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Structural Design, Approval, and Monitoring of a UBC Tall Wood Building

https://research.thinkwood.com/en/permalink/catalogue1252
Year of Publication
2017
Topic
Serviceability
Mechanical Properties
Design and Systems
Material
CLT (Cross-Laminated Timber)
Glulam (Glue-Laminated Timber)
Application
Hybrid Building Systems
Author
Tannert, Thomas
Moudgil, Ermanu
Organization
Structures Congress
Publisher
American Society of Civil Engineers
Year of Publication
2017
Country of Publication
United States
Format
Conference Paper
Material
CLT (Cross-Laminated Timber)
Glulam (Glue-Laminated Timber)
Application
Hybrid Building Systems
Topic
Serviceability
Mechanical Properties
Design and Systems
Keywords
Vertical Shrinkage
Horizontal Building Vibration
Structural Performance
Concrete Core
Brock Commons
Language
English
Conference
Structures Congress 2017
Research Status
Complete
Notes
April 6–8, 2017, Denver, Colorado
Summary
In this paper, we discuss the structural design of one of the tallest timber-based hybrid buildings in the world: the 18 storey, 53 meter tall student residence on the campus of the University of British Columbia in Vancouver. The building is of hybrid construction: 17 storeys of mass wood construction on top of one storey of concrete construction. Two concrete cores containing vertical circulation provide the required lateral resistance. The timber system is comprised of cross-laminated timber panels, which are point supported on glued-laminated timber columns and steel connections between levels. In addition to providing more than 400 beds for students, the building will serve as an academic site to monitor and study its structural performance, specifically horizontal building vibration and vertical shrinkage considerations. We present the challenges relating to the approval process of the building and discuss building code compliance issues.
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Capacity-Based Design for Cross-Laminated Timber Buildings

https://research.thinkwood.com/en/permalink/catalogue1255
Year of Publication
2017
Topic
Mechanical Properties
Connections
Material
CLT (Cross-Laminated Timber)
Application
Wood Building Systems
Shear Walls
Author
Shahnewaz, Md
Tannert, Thomas
Alam, Shahria
Popovski, Marjan
Organization
Structures Congress
Publisher
American Society of Civil Engineers
Year of Publication
2017
Country of Publication
United States
Format
Conference Paper
Material
CLT (Cross-Laminated Timber)
Application
Wood Building Systems
Shear Walls
Topic
Mechanical Properties
Connections
Keywords
In-Plane Stiffness
Strength
Non-Linear Springs
Finite Element Analysis
Hysteretic Behaviour
Cyclic Loading
Language
English
Conference
Structures Congress 2017
Research Status
Complete
Notes
April 6–8, 2017, Denver, Colorado
Summary
The use of cross-laminated timber (CLT) in residential and non-residential buildings is becoming increasingly popular in North America. While the 2016 supplement to the 2014 edition of the Canadian Standard for Engineering Design in Wood, CSAO86, provides provisions for CLT structures used in platform type applications, it does not provide guidance for the in-plane stiffness and strength of CLT shearwalls. The research presented in this paper investigated the in-plane stiffness and strength of CLT shearwalls with different connections for platform-type construction. Finite element analyses were conducted where the CLT panels were modelled as an orthotropic elastic material, and non-linear springs were used for the connections. The hysteretic behaviour of the connections under cyclic loading was calibrated from quasi-static tests; the full model of wall assemblies was calibrated using experimental tests on CLT shearwalls. A parametric study was conducted that evaluated the change of strength and stiffness of walls with the change in a number of connectors. Finally, a capacity-based design procedure is proposed that provides engineers with guidance for designing platform-type CLT buildings. The philosophy of the procedure is to design the CLT buildings such that all non-linear deformations and energy dissipation occurs in designated connections, while all other connections and the CLT panels are designed with sufficient over-strength to remain linear elastic.
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48 records – page 1 of 5.