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Achieving Sustainable Urban Buildings with Seismically Resilient Mass Timber Core Wall and Floor System

https://research.thinkwood.com/en/permalink/catalogue2802
Topic
Design and Systems
Seismic
Material
CLT (Cross-Laminated Timber)
Glulam (Glue-Laminated Timber)
Application
Cores
Walls
Floors
Wood Building Systems
Organization
Portland State University
Country of Publication
United States
Material
CLT (Cross-Laminated Timber)
Glulam (Glue-Laminated Timber)
Application
Cores
Walls
Floors
Wood Building Systems
Topic
Design and Systems
Seismic
Keywords
Hold-Down
Seismic Performance
Core Walls
Parametric Analysis
Deformation Capacity
Overstrength
Mid-Rise
High-Rise
Tall Wood Buildings
Research Status
In Progress
Notes
Project contact is Peter Dusicka at Portland State University
Summary
The urgency in increasing growth in densely populated urban areas, reducing the carbon footprint of new buildings, and targeting rapid return to occupancy following disastrous earthquakes has created a need to reexamine the structural systems of mid- to high-rise buildings. To address these sustainability and seismic resiliency needs, the objective of this research is to enable an all-timber material system in a way that will include architectural as well as structural considerations. Utilization of mass timber is societally important in providing buildings that store, instead of generate, carbon and increase the economic opportunity for depressed timber-producing regions of the country. This research will focus on buildings with core walls because those building types are some of the most common for contemporary urban mid- to high-rise construction. The open floor layout will allow for commercial and mixed-use occupancies, but also will contain significant technical knowledge gaps hindering their implementation with mass timber. The research plan has been formulated to fill these gaps by: (1) developing suitable mid- to high-rise archetypes with input from multiple stakeholders, (2) conducting parametric system-level seismic performance investigations, (3) developing new critical components, (4) validating the performance with large-scale experimentation, and (5) bridging the industry information gaps by incorporating teaching modules within an existing educational and outreach framework. Situated in the heart of a timber-producing region, the multi-disciplinary team will utilize the local design professional community with timber experience and Portland State University's recently implemented Green Building Scholars program to deliver technical outcomes that directly impact the surrounding environment. Research outcomes will advance knowledge at the system performance level as well as at the critical component level. The investigated building system will incorporate cross laminated timber cores, floors, and glulam structural members. Using mass timber will present challenges in effectively achieving the goal of desirable seismic performance, especially seismic resiliency. These challenges will be addressed at the system level by a unique combination of core rocking combined with beam and floor interaction to achieve non-linear elastic behavior. This system behavior will eliminate the need for post-tensioning to achieve re-centering, but will introduce new parameters that can directly influence the lateral behavior. This research will study the effects of these parameters on the overall building behavior and will develop a methodology in which designers could use these parameters to strategically control the building seismic response. These key parameters will be investigated using parametric numerical analyses as well as large-scale, sub-system experimentation. One of the critical components of the system will be the hold-down, a device that connects the timber core to the foundation and provides hysteretic energy dissipation. Strength requirements and deformation demands in mid- to high-rise buildings, along with integration with mass timber, will necessitate the advancement of knowledge in developing this low-damage component. The investigated hold-down will have large deformation capability with readily replaceable parts. Moreover, the hold-down will have the potential to reduce strength of the component in a controlled and repeatable way at large deformations, while maintaining original strength at low deformations. This component characteristic can reduce the overall system overstrength, which in turn will have beneficial economic implications. Reducing the carbon footprint of new construction, linking rural and urban economies, and increasing the longevity of buildings in seismic zones are all goals that this mass timber research will advance and will be critical to the sustainable development of cities moving forward.
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Ductility and Overstrength of Dowelled LVL and CLT Connections Under Cyclic Loading

https://research.thinkwood.com/en/permalink/catalogue1504
Year of Publication
2016
Topic
Connections
Mechanical Properties
Material
CLT (Cross-Laminated Timber)
LVL (Laminated Veneer Lumber)
Author
Ottenhaus, Lisa-Mareike
Li, Minghao
Smith, Tobias
Quenneville, Pierre
Year of Publication
2016
Country of Publication
Austria
Format
Conference Paper
Material
CLT (Cross-Laminated Timber)
LVL (Laminated Veneer Lumber)
Topic
Connections
Mechanical Properties
Keywords
Ductility
Overstrength
Cyclic Loading
Monotonic Loading
Dowels
Ductile Failure
Brittle Failure
Language
English
Conference
World Conference on Timber Engineering
Research Status
Complete
Notes
August 22-25, 2016, Vienna, Austria p. 325-333
Summary
This paper presents an experimental study on ductility and overstrength of dowelled connections. Connection ductility and overstrength derived from monotonic testing are often used in timber connection design in the context of seismic loading, based on the assumption that these properties are similar under monotonic and cyclic loading. This assumption could possibly lead to non-conservative connection design. Therefore, it is necessary to quantify ductility and overstrength for cyclic loading and contrast them with their monotonic performance. For this purpose, monotonic and quasi-static cyclic experimental tests were performed on dowelled LVL and CLT connections. The experimental results were also compared with strength predictions from state-of-the-art analytical models in literature that were verified for ductile and brittle failure under monotonic loading. This work also allowed investigation into a generally applicable overstrength factor for push-pull loaded dowelled connections.
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Force Based Design Guideline for Timber-Steel Hybrid Structures: Steel Moment Resisting Frames with CLT Infill Walls

https://research.thinkwood.com/en/permalink/catalogue83
Year of Publication
2015
Topic
Design and Systems
Seismic
Material
CLT (Cross-Laminated Timber)
Application
Wood Building Systems
Author
Tesfamariam, Solomon
Stiemer, Siegfried
Bezabeh, Matiyas
Goertz, Caleb
Popovski, Marjan
Goda, Katsuichiro
Organization
University of British Columbia
Year of Publication
2015
Country of Publication
Canada
Format
Report
Material
CLT (Cross-Laminated Timber)
Application
Wood Building Systems
Topic
Design and Systems
Seismic
Keywords
Overstrength
Ductility
National Building Code of Canada
Timber-Steel Hybrid
Office Buildings
Residential Buildings
Language
English
Research Status
Complete
Summary
Provincial code changes have been made to allow construction of light wood-frame buildings up to 6 storeys in order to satisfy the urban housing demand in western Canadian cities. It started in 2009 when the BC Building Code was amended to increase the height limit for wood-frame structures from four to six. Recently, provinces of Quebec, Ontario and Alberta followed suit. While wood-frame construction is limited to six storeys, some innovative wood-hybrid systems can go to greater heights. In this report, a feasibility study of timber-based hybrid buildings is described as carried out by The University of British Columbia (UBC) in collaboration with FPInnovations. This project, funded through BC Forestry Innovation Investment's (FII) Wood First Program, had an objective to develop design guidelines for a new steel-timber hybrid structural system that can be used as part of the next generation "steel-timber hybrid structures" that is limited in scope to 20 storey office or residential buildings. ...
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Innovative Technology for Mass Timber and Hybrid Modular Buildings

https://research.thinkwood.com/en/permalink/catalogue2801
Topic
Design and Systems
Seismic
Wind
Connections
Application
Wood Building Systems
Hybrid Building Systems
Organization
Oregon State University
Country of Publication
United States
Application
Wood Building Systems
Hybrid Building Systems
Topic
Design and Systems
Seismic
Wind
Connections
Keywords
Mass Timber
Modular Construction
Ductility
Overstrength
High-Rise
Tall Wood Buildings
Interdisciplinary Research
Wind Tunnel Test
Research Status
In Progress
Notes
Project contact is Erica Fischer at Oregon State University
Summary
This Faculty Early Career Development (CAREER) award will create innovative building technology that will enable mass timber modular construction as a building solution to many of the issues the nation's major cities face today. The architecture, engineering, and construction (AEC) sector is on the cusp of a significant disruption that will change the way buildings are manufactured, assembled, and designed, the catalyst of which is the integration of building information models (BIM) and automated construction and manufacturing. This disruption will significantly impact structural engineers. With the streamlining of building manufacturing, assembling, and design, engineers will need to take advantage of three opportunities: (1) design for constructability, (2) design for manufacturing, and (3) design for the whole life of the building (considering future modifications, maintenance, and easily replacing parts of the building). Modular construction, as one method to take advantage of these three opportunities, can address labor and housing shortages that exist in almost every U.S. city today and also can provide rapid construction methods for post-disaster reconstruction and additional patient care facilities. This research will contribute to the state of Oregon’s economy, which has made significant investments in mass timber production, manufacturing, and research. This research will be complemented through the development of best practices for using interdisciplinary, collaborative classroom environments to enhance engineering identities of underrepresented minorities and women at the graduate level. This award will support the National Science Foundation (NSF) role in the National Earthquake Hazards Reduction Program and the National Windstorm Impact Reduction Program. The specific goal of this research is to develop a novel framework for robust and ductile mass timber modular construction that can be applied to buildings with varying lateral force resisting systems. Through this framework, the relationship between the rigidity of modular interconnections and overall structural behavior will be investigated. The research objectives of this project are to: (1) quantify the demands in interconnections that provide ductility when the building framing is subjected to combined gravity and lateral forces (seismic and wind); (2) quantify the impact of interconnection configuration and design on the ability of interconnections to meet the strength and serviceability performance criteria for mass timber high-rise modular buildings; (3) quantify ductility and overstrength for mass timber modular construction and explore applicability of conventional seismic performance factors and how these factors influence the adjusted collapse margin ratio for archetype buildings; (4) explore the influence of interconnection stiffness on the behavior of high-rise modular mass timber buildings subjected to wind demands; and (5) explore the relationship between team-focused and interdisciplinary educational practices with engineering identity and knowledge retention. New connection technology will be created and its contribution to the overall building behavior will be investigated through a rigorous testing plan and complex physics-based numerical simulations of archetype buildings subjected to combined gravity and lateral loads (seismic and wind). This research is a critical first step to develop innovative technology that will change how buildings are designed, manufactured, and assembled. This project will enable the Principal Investigator to establish interdisciplinary research, teaching, and mentorship in the area of mass timber and hybrid construction. This research will use the NSF-supported Natural Hazards Engineering Research Infrastructure (NHERI) Boundary Layer Wind Tunnel facility at the University of Florida. Experimental datasets will be archived in the NHERI Data Depot (https://www.DesignSafe-ci.org) and made publicly available.
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Overstrength of Dowelled CLT Connections Under Monotonic and Cyclic Loading

https://research.thinkwood.com/en/permalink/catalogue1385
Year of Publication
2018
Topic
Connections
Mechanical Properties
Seismic
Material
CLT (Cross-Laminated Timber)
Author
Ottenhaus, Lisa-Mareike
Li, Minghao
Smith, Tobias
Quenneville, Pierre
Publisher
Springer Netherlands
Year of Publication
2018
Country of Publication
Netherlands
Format
Journal Article
Material
CLT (Cross-Laminated Timber)
Topic
Connections
Mechanical Properties
Seismic
Keywords
Overstrength
Ductility
Three Point Bending Test
Fasteners
Yield Moment
Monotonic Loading
Cyclic Loading
Steel Dowels
Steel Plates
Language
English
Research Status
Complete
Series
Bulletin of Earthquake Engineering
ISSN
1573-1456
Summary
This paper presents an evaluation of overstrength based on an experimental study on dowelled connections in cross-laminated timber (CLT). Connection overstrength needs to be well understood in order to ensure that ductile system behaviour and energy dissipation can be achieved under seismic loading. Overstrength is defined as the difference between the code-based strength, using characteristic material strengths, and the 95th 4 percentile of the true strength distribution. Many aspects contribute to total connection overstrength, which makes its definition challenging. In this study, half-hole embedment tests were performed on CLT to establish embedment strength properties and three point bending tests were performed to determine the fastener yield moment. Different connection layouts, making use of mild steel dowels and an internal steel plate, were tested under monotonic and cyclic loading to evaluate theoretically determined overstrength values and study the influence of cyclic loading on overstrength. Experimental results were compared with strength predictions from code provisions and analytical models for ductile response under monotonic loading. It was found that cyclic loading does not significantly influence overstrength for connections that respond in a mixed-mode ductile way indicating that in future more expedient monotonic test campaigns could be used. This work also provides further experimental data and theoretical considerations necessary for the estimation of a generally applicable overstrength factor for dowelled CLT connections.
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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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Seismic Base Shear Modification Factors for Timber-Steel Hybrid Structure: Steel Moment Resisting Frames with CLT Infill Walls

https://research.thinkwood.com/en/permalink/catalogue1723
Year of Publication
2016
Topic
Seismic
Mechanical Properties
Material
CLT (Cross-Laminated Timber)
Application
Hybrid Building Systems
Author
Bezabeh, Matiyas
Tesfamariam, Solomon
Popovski, Marjan
Year of Publication
2016
Country of Publication
Austria
Format
Conference Paper
Material
CLT (Cross-Laminated Timber)
Application
Hybrid Building Systems
Topic
Seismic
Mechanical Properties
Keywords
Timber-Steel Hybrid
Overstrength
Ductility
Force Modification Factors
Nonlinear Pushover Analysis
Adjusted Collapse Margin Ratios
Language
English
Conference
World Conference on Timber Engineering
Research Status
Complete
Notes
August 22-25, 2016, Vienna, Austria p. 4647-4654
Summary
In this paper, over-strength and ductility-related force modification factors are developed and validated using a collapse risk assessment approach for a timber-steel hybrid structure. The hybrid structure incorporates Cross Laminated Timber (CLT) infill walls within steel moment resisting frames. Following the FEMA P695 procedure...
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Technical Guide for Evaluation of Seismic Force Resisting Systems and Their Force Modification Factors for Use in the National Building Code of Canada with Concepts Illustrated Using a Cantilevered Wood CLT Shear Wall Example

https://research.thinkwood.com/en/permalink/catalogue2804
Year of Publication
2021
Topic
Seismic
Material
CLT (Cross-Laminated Timber)
Application
Shear Walls
Author
DeVall, Ron
Popovski, Marjan
McFadden, Jasmine
Organization
National Research Council Canada, Canadian Construction Materials Centre
Publisher
National Research Council Canada
Year of Publication
2021
Country of Publication
Canada
Format
Report
Material
CLT (Cross-Laminated Timber)
Application
Shear Walls
Topic
Seismic
Keywords
Seismic Force Resisting System
Force Modification Factor
Ductility Factor
Overstrength
Non-linear Dynamic Analysis
National Building Code of Canada
Alternative Design Solution
Shear Walls
Language
English
Research Status
Complete
ISBN
978-0-660-39263-9
Summary
The objective of this guideline is to provide a simple, systematic, and sufficient procedure for evaluating the performance of Seismic Force Resisting Systems (SFRSs) and to determine the appropriate ductilityrelated (Rd) and over-strength related (Ro) force modification factors for implementation in the National Building Code of Canada (NBC). The procedure relies on the application of non-linear dynamic analysis for quantification of the seismic performance of the SFRS. Note that the procedure is also suitable for assessing force modification factors (RdRo values) of systems already implemented in the NBC. The audience for this guideline are those (called the “project study team” in this document) who submit proposals for new SFRSs with defined RdRo values to the NBC for inclusion in Subsection 4.1.8., Earthquake Loads and Effects, of Division B of the NBC. This guideline can also be used by a team performing an alternative design solution for a specific project and seeking acceptance from authority having jurisdiction. In such cases, not all aspects of this guideline (e.g., having different archetypes) will be needed.
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Free
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Wind and Earthquake Design Framework for Tall Wood-Concrete Hybrid System

https://research.thinkwood.com/en/permalink/catalogue2143
Year of Publication
2019
Topic
Seismic
Wind
Material
CLT (Cross-Laminated Timber)
Application
Wood Building Systems
Author
Tesfamariam, Solomon
Bezabeh, Matiyas
Skandalos, Konstantinos
Martinez, Edel
Dires, Selamawit
Bitsuamlak, Girma
Goda, Katsuichiro
Year of Publication
2019
Country of Publication
Canada
Format
Report
Material
CLT (Cross-Laminated Timber)
Application
Wood Building Systems
Topic
Seismic
Wind
Keywords
Tall Wood
Seismic design factors
Wind tunnel test
Ductility Factors
Timber-reinforced concrete
Force Modification Factors
Probabilistic Model
Wind Load
Overstrength seismic force
Language
English
Research Status
Complete
Notes
DOI 10.14288/1.0380777
Summary
Advancement in engineered wood products altered the existing building height limitations and enhanced wooden structural members that are available on the market. These coupled with the need for a sustainable and green solution to address the ever-growing urbanization demand, avails wood as possible candidate for primary structural material in the construction industry. To this end, several researches carried out in the past decade to come up with sound structural solutions using a timber based structural system. Green and Karsh (2012) introduced the FFTT system; Tesfamariam et al. (2015) developed force-based design guideline for steel infilled with CLT shear walls, and SOM (2013) introduced the concrete jointed mass timber hybrid structural concepts. In this research, the basic structural concepts proposed by SOM (2013) is adopted. The objective of this research is to develop a wind and earthquake design guideline for concrete jointed tall mass timber buildings in scope from 10- to 40-storey office or residential buildings. The specific objective of this research is as follow: Wind serviceability design guideline for hybrid mass-timber structures. Calibration of design wind load factors for the serviceability wind design of hybrid tall mass timber structures. Guidelines to perform probabilistic modeling, reliability assessment, and wind load factor calibration. Overstrength related modification factor Ro and ductility related modification factor Rd for future implementation in the NBCC. Force-based design guideline following the capacity based design principles.
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Free
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Wood-Steel Hybrid Seismic Force Resisting Systems: Seismic Ductility

https://research.thinkwood.com/en/permalink/catalogue330
Year of Publication
2012
Topic
Design and Systems
Material
CLT (Cross-Laminated Timber)
Application
Hybrid Building Systems
Author
Dickof, Carla
Stiemer, Siegfried
Tesfamariam, Solomon
Year of Publication
2012
Country of Publication
New Zealand
Format
Conference Paper
Material
CLT (Cross-Laminated Timber)
Application
Hybrid Building Systems
Topic
Design and Systems
Keywords
Timber-Steel Hybrid
Overstrength
Ductility
Stiffness
Seismic Force Resisting System
Pushover Response
Language
English
Conference
World Conference on Timber Engineering
Research Status
Complete
Notes
July 15-19, 2012, Auckland, New Zealand
Summary
North American building codes currently provide strict limits on height of wood structures, where for example, in Canada wood structures are limited to 4 or 5 storeys. This paper examines wood-steel hybrid system to increase seismic force resistance beyo...
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10 records – page 1 of 1.