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32 records – page 1 of 4.

Seismic performance assessment of a multi-story bamboo frame structure

https://research.thinkwood.com/en/permalink/catalogue3315
Year of Publication
2023
Topic
Mechanical Properties
Author
Zhao, Jian-Chen
Qiu, Hong-Xing
Organization
Southeast University
Publisher
Elsevier
Year of Publication
2023
Format
Journal Article
Topic
Mechanical Properties
Keywords
Bamboo Materials
Multi-storey Bamboo Frame
Dynamic Analysis
Laminated Bamboo
Seismic Performance
Research Status
Complete
Series
Advances in Bamboo Science
Summary
As a building material, engineered bamboo has caught attention around the world due to its advantages in energy conservation and environmental protection. The seismic performance of bamboo buildings needs to be evaluated to further promote the use of bamboo materials in building construction. We studied the seismic response of a 3-story bamboo frame structure numerically using nonlinear dynamic time history analysis. A simplified modeling method for bamboo column-beam joints was proposed in the numerical model. The hysteresis behaviour of the joint was simulated by Pinching 4 material in OpenSEES, with the parameters calibrated through test results. Comparative analysis shows that the proposed modeling method could reasonably reflect the pinching effect and the degradation of the joint hysteretic behavior. A total of 20 ground motions with three intensities were involved in the nonlinear dynamic analysis. The results demonstrate that the frame meets target performance levels, providing evidence for the further popularization of engineered bamboo structures.
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Seismic performance evaluation of innovative balloon type CLT rocking shear walls

https://research.thinkwood.com/en/permalink/catalogue3133
Year of Publication
2022
Topic
Seismic
Material
CLT (Cross-Laminated Timber)
Application
Shear Walls
Author
Yang, T.Y.
Lepine-Lacroix, S.
Guerrero, J.A. Ramos
McFadden, J.B.W.
Al-Janabi, M.A.Q.
Organization
The University of British Columbia
National Research Council Canada
Al-Nahrain University
Publisher
Elsevier
Year of Publication
2022
Format
Journal Article
Material
CLT (Cross-Laminated Timber)
Application
Shear Walls
Topic
Seismic
Keywords
Rocking Shear Walls
CLT Shear Walls
Seismic Performance
Nonlinear Finite Element Model
Research Status
Complete
Series
Resilient Cities and Structures
Summary
Balloon type cross laminated timber (CLT) rocking shear walls are a novel seismic force resisting system. In this paper, the seismic performance of four 12-story balloon type CLT rocking shear walls, designed by a structural engineering firm located in Vancouver (Canada) using the performance-based design procedure outlined in the technical guideline published by the Canadian Construction Materials center (CCMC)/National Research Council Canada (NRC), is assessed. The seismic performance of the prototype CLT rocking shear walls was investigated using nonlinear time history analyses. Robust nonlinear finite element models were developed using OpenSees and the nonlinear behavior of the displacement-controlled components was calibrated using available experimental data. A detailed site-specific hazard analysis was conducted and sets of ground motions suitable for the prototype buildings were selected. The ground motions were used in a series of incremental dynamic analyses (IDAs) to quantify the adjustable collapse margin ratio (ACMR) of the prototype balloon type CLT rocking shear walls. The results show that the prototype balloon type CLT rocking shear walls designed using the performance-based design procedure outlined in the CCMC/NRC technical guideline have sufficient ACMR when compared to the acceptable limits recommended by FEMA P695.
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North American Research Needs Assesment for Mass Timber

https://research.thinkwood.com/en/permalink/catalogue3222
Year of Publication
2021
Topic
General Information
Material
CLT (Cross-Laminated Timber)
Author
Zelinka, Samuel
Williamson, Tom
Martinson, Karen
Ritter, Michael A.
Organization
Forest Products Laboratory
Year of Publication
2021
Format
Conference Paper
Material
CLT (Cross-Laminated Timber)
Topic
General Information
Keywords
Mass Timber
North America
Seismic Performance
Fire Performance
Conference
World Conference on Timber Engineering
Research Status
Complete
Summary
The 2nd Mass Timber Research Needs Assessment Workshop was held on November 13-14, 2018 at the US Forest Service, Forest Products Laboratory (FPL). The purpose of the workshop was to convene a group of experts on cross laminated timber and mass timber to develop a list of prioritized research needs for the North American mass timber industry. The workshop had over 100 attendees including design professionals, academics, industry leaders, and government employees. The attendees generated a list of over 117 research needs. After the workshop, the list of 117 research needs was prioritized through the use of an online survey. This paper presents highlights of the top research needs generated at the 2nd Mass Timber Research Needs Assessment Meeting.
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Nonlinear Static Seismic Response of a Building Equipped with Hybrid Cross-Laminated Timber Floor Diaphragms and Concentric X-Braced Steel Frames

https://research.thinkwood.com/en/permalink/catalogue2761
Year of Publication
2021
Topic
Seismic
Material
CLT (Cross-Laminated Timber)
Steel-Timber Composite
Application
Floors
Author
Roncari, Andrea
Gobbi, Filippo
Loss, Cristiano
Organization
University of British Columbia
University of Trento
Publisher
MDPI
Year of Publication
2021
Format
Journal Article
Material
CLT (Cross-Laminated Timber)
Steel-Timber Composite
Application
Floors
Topic
Seismic
Keywords
Seismic Design
Hybrid Structures
Lateral Resistance
Semi-rigid Diaphragms
Load Distribution
Seismic Performance
Pushover Analysis
Nonlinear Static Analysis
Finite Element Model
Research Status
Complete
Series
Buildings
Summary
Simplified seismic design procedures mostly recommend the adoption of rigid floor diaphragms when forming a building’s lateral force-resisting structural system. While rigid behavior is compatible with many reinforced concrete or composite steel-concrete floor systems, the intrinsic stiffness properties of wood and ductile timber connections of timber floor slabs typically make reaching a such comparable in-plane response difficult. Codes or standards in North America widely cover wood-frame construction, with provisions given for both rigid and flexible floor diaphragms designs. Instead, research is ongoing for emerging cross-laminated-timber (CLT) and hybrid CLT-based technologies, with seismic design codification still currently limited. This paper deals with a steel-CLT-based hybrid structure built by assembling braced steel frames with CLT-steel composite floors. Preliminary investigation on the performance of a 3-story building under seismic loads is presented, with particular attention to the influence of in-plane timber diaphragms flexibility on the force distribution and lateral deformation at each story. The building complies with the Italian Building Code damage limit state and ultimate limit state design requirements by considering a moderate seismic hazard scenario. Nonlinear static analyses are performed adopting a finite-element model calibrated based on experimental data. The CLT-steel composite floor in-plane deformability shows mitigated effects on the load distribution into the bracing systems compared to the ideal rigid behavior. On the other hand, the lateral deformation always rises at least 17% and 21% on average, independently of the story and load distribution along the building’s height.
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Expanding Wood Use Towards 2025: Seismic Performance of Braced Mass Timber Frames, Year 2

https://research.thinkwood.com/en/permalink/catalogue2597
Year of Publication
2020
Topic
Design and Systems
Seismic
Material
Glulam (Glue-Laminated Timber)
Application
Wood Building Systems
Author
Chen, Zhiyong
Popovski, Marjan
Organization
FPInnovations
Year of Publication
2020
Format
Report
Material
Glulam (Glue-Laminated Timber)
Application
Wood Building Systems
Topic
Design and Systems
Seismic
Keywords
Seismic Performance
Connections
Connection Systems
Multi-Story
Research Status
Complete
Summary
Braced timber frames (BTFs) are one of the most efficient structural systems to resist lateral loads induced by earthquakes or high winds. Although BTFs are implemented as a system in the National Building Code of Canada (NBCC), no design guidelines currently exist in CSA O86. That not only leaves these efficient systems out of reach of designers, but also puts them in danger of being eliminated from NBCC. The main objective of this project is to generate the technical information needed for development of design guidelines for BTFs as a lateral load resisting system in CSA O86. The seismic performance of 30 BTFs with riveted connections was studied last year by conducting nonlinear dynamic analysis; and also 15 glulam brace specimens using bolted connections were tested under cyclic loading. In the second year of the project, a relationship between the connection and system ductility of BTFs was derived based on engineering principles. The proposed relationship was verified against the nonlinear pushover analysis results of single- and multi-storey BTFs with various building heights. The influence of the connection ductility, the stiffness ratio, and the number of tiers and storeys on the system ductility of BTFs was investigated using the verified relationship. The minimum connection ductility for different categories (moderately ductile and limited ductility) of BTFs was estimated.
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Fragility-based methodology for evaluating the time-dependent seismic performance of post-tensioned timber frames

https://research.thinkwood.com/en/permalink/catalogue2871
Year of Publication
2020
Topic
Seismic
Application
Frames
Author
Granello, Gabriele
Palermo, Alessandro
Pampanin, Stefano
Organization
University of Canterbury
ETH Zurich
Sapienza University of Rome
Publisher
SAGE Journals
Year of Publication
2020
Format
Journal Article
Application
Frames
Topic
Seismic
Keywords
Pres-Lam
Post-Tensioned Timber
Fragility Analysis
Seismic Performance
Research Status
Complete
Series
Earthquake Spectra
Summary
Since 2010, the construction of post-tensioned wooden buildings (Pres-Lam) has been growing rapidly worldwide. Pres-Lam technology combines unbonded post-tensioning tendons and supplemental damping devices to provide moment capacity to beam–column, wall–foundation, or column–foundation connections. In low seismic areas, designers may choose not to provide additional damping, relying only on the post-tensioning contribution. However, post-tensioning decreases over time due to creep phenomena arising in compressed timber members. As a consequence, there is a reduction of the clamping forces between the elements. This reduction affects the seismic response of Pres-Lam buildings in the case of low- and high-intensity earthquakes. Therefore, understanding and accounting for the post-tensioning losses and their uncertainty are paramount for a robust assessment of the safety of Pres-Lam constructions. So far, however, there have been no comprehensive studies which tackle the overall seismic performance of such systems in the presence of time-varying post-tension losses and the associated uncertainty. This study tackles this research gap by introducing a comprehensive seismic evaluation of Pres-Lam systems based on time-dependent fragility curves. The proposed fragility analysis is specifically designed to account systematically for time-varying post-tension losses and the related uncertainty. The method is applied to two case studies, designed, respectively, with and without supplemental damping devices. In terms of structural performance, results show that the use of additional dissipaters mitigates the effect of post-tensioning loss for earthquakes of high intensity. Conversely, performance under low-intensity earthquakes is strongly dependent on the post-tensioning value, as the reduction of stiffness due to the anticipated rocking motion activation would lead to damage to non-structural elements.
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Combination of Steel Plate Shear Walls and Timber Moment Frames for Improved Seismic Performance

https://research.thinkwood.com/en/permalink/catalogue2735
Year of Publication
2020
Topic
Seismic
Material
CLT (Cross-Laminated Timber)
Application
Shear Walls
Frames
Author
Iqbal, Asif
Todorov, Borislav
Billah, Muntasir
Year of Publication
2020
Format
Conference Paper
Material
CLT (Cross-Laminated Timber)
Application
Shear Walls
Frames
Topic
Seismic
Keywords
Timber Moment Frames
Steel Plate Shear Walls
Hybrid
Seismic Performance
Interstory Drifts
Conference
World Conference on Earthquake Engineering
Research Status
Complete
Summary
Recent interests in adopting sustainable materials and developments in construction technology have created a trend of aiming for greater heights with timber buildings. With the increased height these buildings are subjected to higher level of lateral load demand. A common and efficient way to increase capacity is to use shearwalls, which can resist significant part of the load on the structures. Prefabricated mass timber panels such as those made of Cross-Laminated Timber (CLT) can be used to form the shearwalls. But due to relatively low stiffness value of timber it is often difficult to keep the maximum drifts within acceptable limit prescribed by building codes. It becomes necessary to either increase wall sizes to beyond available panel dimensions or use multiple or groups of walls spread over different locations over the floor plan. Both of the options are problematic from the economic and functional point of view. One possible alternative is to adopt a Hybrid system, using Steel Plate Shear Walls (SPSW) with timber moment frames. The SPSW has much higher stiffness and combined with timber frames it can reduce overall building drifts significantly. Frames with prefabricated timber members have considerable lateral load capacity. For structures located in seismic regions the system possesses excellent energy dissipation ability with combination of ductile SPSW and yielding elements within the frames. This paper investigates combination of SPSW with timber frames for seismic applications. Numerical model of the system has been developed to examine the interaction between the frames and shear walls under extreme lateral load conditions. Arrangements of different geometries of frames and shear walls are evaluated to determine their compatibility and efficiency in sharing lateral loads. Recommendations are presented for optimum solutions as well as practical limits of applications.
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Solutions for Upper Mid-Rise and High-Rise Mass Timber Construction: Seismic Performance of Braced Mass Timber Frames, Year 1

https://research.thinkwood.com/en/permalink/catalogue2640
Year of Publication
2019
Topic
Seismic
Design and Systems
Material
Glulam (Glue-Laminated Timber)
Application
Frames
Author
Chen, Zhiyong
Popovski, Marjan
Symons, Paul
Organization
FPInnovations
Year of Publication
2019
Format
Report
Material
Glulam (Glue-Laminated Timber)
Application
Frames
Topic
Seismic
Design and Systems
Keywords
Lateral Load
Seismic Performance
Braced Frames
Research Status
Complete
Summary
Braced mass timber (MT) frames are one of the most efficient structural systems to resist lateral loads induced by earthquakes or high winds. Although braced frames are presented as a system in the National Building Code of Canada (NBCC), no design guidelines currently exist in CSA O86. That not only leaves these efficient systems out of reach of designers, but also puts them in danger of being eliminated from NBCC. The main objective of this project was to develop the technical information needed for development of design guidelines for braced MT frames as a lateral load resisting system in CSA O86. In the first year of the project, the seismic performance of thirty (30) braced MT frames with riveted connections with various numbers of storeys, storey heights, and bay aspect ratios were studied by conducting non-linear pushover and dynamic time-history analyses. Also, fifteen (15) glulam brace specimens using bolted connections with different slenderness ratios were tested under monotonic and cyclic loading. Results from this multi-year project will form the basis for developing comprehensive design guidelines for braced frames in CSA O86.
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Research Needs Assessment for the Mass Timber Industry: Proceedings of the 2nd North American Mass Timber Research Needs Workshop

https://research.thinkwood.com/en/permalink/catalogue2164
Year of Publication
2019
Topic
General Information
Material
CLT (Cross-Laminated Timber)
DLT (Dowel Laminated Timber)
NLT (Nail-Laminated Timber)
Glulam (Glue-Laminated Timber)
Timber-Concrete Composite
Application
Shear Walls
Walls
Wood Building Systems
Floors
Columns
Bridges and Spans
Author
Zelinka, Samuel
Williamson, Tom
Martinson, Karen
Ritter, Michael
Organization
Forest Products Laboratory
Year of Publication
2019
Format
Report
Material
CLT (Cross-Laminated Timber)
DLT (Dowel Laminated Timber)
NLT (Nail-Laminated Timber)
Glulam (Glue-Laminated Timber)
Timber-Concrete Composite
Application
Shear Walls
Walls
Wood Building Systems
Floors
Columns
Bridges and Spans
Topic
General Information
Keywords
Mass Timber
North America
Research Needs
Research Priorities
Seismic Performance
Fire Performance
Research Status
Complete
Summary
The 2nd Mass Timber Research Needs Assessment was held on November 13–14, 2018, at the USDA Forest Service, Forest Products Laboratory (FPL). The workshop was co-sponsored by FPL, WoodWorks, and the U.S. Endowment for Forestry and Communities. The purpose of the workshop was to gather a diverse group of people with expertise in mass timber, in particular cross-laminated timber, to discuss and prioritize research needed to move the mass timber industry forward in North America. The workshop was attended by more than 100 design professionals, researchers, manufacturers, industry leaders, and government employees. The meeting resulted in a list of 117 research needs. Following the meeting, the list of research needs was prioritized through an online survey. This report presents the prioritized research needs of the mass timber industry in North America. Also included in the appendixes are the formal minutes of the workshop, a list of participants, and the original scribe notes.
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Numerical Study of Alternative Seismic-Resisting Systems for CLT Buildings

https://research.thinkwood.com/en/permalink/catalogue2176
Year of Publication
2018
Topic
Connections
Design and Systems
Material
CLT (Cross-Laminated Timber)
Application
Walls
Shear Walls
Author
Loss, Cristiano
Pacchioli, Stefano
Polastri, Andrea
Casagrande, Daniele
Pozza, Luca
Smith, Ian
Publisher
MDPI
Year of Publication
2018
Format
Journal Article
Material
CLT (Cross-Laminated Timber)
Application
Walls
Shear Walls
Topic
Connections
Design and Systems
Keywords
Seismic Performance
Superstructures
Research Status
Complete
Series
Buildings
Summary
Changes to building codes that enable use of materials such as cross-laminated timber (CLT) in mid- and high-rise construction are facilitating sustainable urban development in various parts of the world. Keys to this are the transition to multi-performance-based design approaches along with fewer limitations on heights or the number of storeys in superstructures constructed from combustible materials. Architects and engineers have increased freedom to apply new design and construction concepts and methods, as well as to combine timber with other structural materials. They also have started to develop wall arrangements that optimise interior space layouts and take advantage of the unique characteristics of CLT. This paper discusses the seismic response of multi-story buildings braced with a CLT core and perimeter shear walls anchored to foundations and floor platforms using modern high-capacity angle brackets and hold-downs, or X-Rad connectors. Linear dynamic finite element (FE) models of seismic responses of superstructures of various heights are presented, based on experimentally determined characteristics of wall anchor connections. Particular attention is given to fundamental vibration periods, base shear and uplift forces on walls, as well as inter-story drift. Discussion of FE model results focuses on structural engineering implications and advantages of using CLT to create shear walls, with emphasis on how choice of wall anchoring connections impacts the possible number of storeys and configurations of superstructures. Employing CLT shear walls with X-Rad or other types of high capacity anchoring connections makes possible the creation of building superstructures having eight and potentially more storeys even in high seismicity regions. However, it is important to emphasise that proper selection of suitable arrangements of shear walls for CLT buildings depends on accurate representation of the semi-rigid behaviors of anchoring connections. The linear dynamic analyses presented here demonstrates the need during engineering seismic design practices to avoid use of FE or other design models which do not explicitly incorporate connection flexibilities while estimating parameters like fundamental periods, base shear and uplift forces, as well as inter-story drift.
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32 records – page 1 of 4.