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37 records – page 1 of 4.

Advanced Wood-Based Solutions for Mid-Rise and High-Rise Construction: Structural Performance of Post-Tensioned CLT Shear Walls with Energy Dissipators

https://research.thinkwood.com/en/permalink/catalogue1472
Year of Publication
2018
Topic
Design and Systems
Mechanical Properties
Seismic
Material
CLT (Cross-Laminated Timber)
Glulam (Glue-Laminated Timber)
LVL (Laminated Veneer Lumber)
LSL (Laminated Strand Lumber)
Application
Shear Walls
Author
Chen, Zhiyong
Popovski, Marjan
Symons, Paul
Organization
FPInnovations
Year of Publication
2018
Format
Report
Material
CLT (Cross-Laminated Timber)
Glulam (Glue-Laminated Timber)
LVL (Laminated Veneer Lumber)
LSL (Laminated Strand Lumber)
Application
Shear Walls
Topic
Design and Systems
Mechanical Properties
Seismic
Keywords
Compression Tests
Compression Strength
Energy Dissipation
Post-Tensioned
Pres-Lam
Monotonic Loading
Reverse Cyclic Loading
Research Status
Complete
Summary
The latest developments in seismic design philosophy have been geared towards developing of so called "resilient" or "low damage" innovative structural systems that can reduce damage to the structure while offering the same or higher levels of safety to occupants. One such innovative structural system is the Pres-Lam system that is a wood-hybrid system that utilizes post-tensioned (PT) mass timber components in both rigid-frame and wall-based buildings along with various types of energy disspators. To help implement the Pres-Lam system in Canada and the US, information about the system performance made with North American engineered wood products is needed. That information can later be used to develop design guidelines for the designers for wider acceptance of the system by the design community.Several components influence the performance of the Pres-Lam systems: the load-deformation properties of the engineered wood products under compression, load-deformation and energy dissipation properties of the dissipators used, placement of the dissipators in the system, and the level of post-tensioning force. The influence of all these components on the performance of Pres-Lam wall systems under gravity and lateral loads was investigated in this research project. The research project consisted of two main parts: material tests and system tests.
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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
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
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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Conventional and Novel Timber Steel Hybrid Connections: Testing, Performance and Assessment

https://research.thinkwood.com/en/permalink/catalogue187
Year of Publication
2015
Topic
Connections
Seismic
Material
CLT (Cross-Laminated Timber)
Application
Wood Building Systems
Author
Schneider, Johannes
Organization
University of British Columbia
Year of Publication
2015
Format
Thesis
Material
CLT (Cross-Laminated Timber)
Application
Wood Building Systems
Topic
Connections
Seismic
Keywords
Timber-Steel Hybrid
Fasteners
Quasi-Static
Monotonic Loading
Cyclic Loading
Brackets
Tube Connections
Research Status
Complete
Summary
The focus of this research is the connection between steel frame and the infill wall. Over 100 conventional bracket-type connections with various combinations of bracket and fasteners with cross-laminated timber were tested, investigated and assessed for damage under seismic loading protocols for a hybrid application. An energy-based formulation according to Krätzig was applied to calculate the development of the damage index, and the resulting index was validated with visual observation. Six of the connections were modeled in OpenSees. For the modeling, a CUREE-10 parameter model was chosen to reproduce the test curves. The load-displacement results from both test and model were analyzed; the first method according to ASTM standards, where the envelope curve of the hysteretic results are considered and plotted in an equivalent energy elastic-plastic curve (EEEP). The second analyzing method used, was Krätzig’s damage accumulation model. Throughout all six combinations and both loading directions (parallel- and perpendicular-to-the-grain) a major difference was found in the analyzing methods. The EEEP curve roughly approximates the performance but with the damage accumulation method showed that analysis of the subsequent cycles is required to better reflect the empirical performance of the connections. To avoid the extensive destruction of a bracket type connection after completion of seismic loadings, a new approach was chosen. It was found that a tube connection can obtain comparably similar strength results as a conventional bracket connection. The computed mechanical properties of bracket-type and tube-type connections were compared and evaluated. The new tube connection showed great potential for future timber-steel hybrid structures and their connecting challenge. A total of 27 connection assemblies were tested under quasi-static monotonic and reversed cyclic loads. The tube connections showed two major differences when compared to traditional bracket connections: i) the completely linear elastic behaviour at the beginning, and ii) the continued load increase after yielding. Both phenomena are founded in the geometry of that connector effectively making the novel connector a very promising alternative.
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Cross-Laminated Timber Shear Connections with Double-Angled Self-Tapping Screw Assemblies

https://research.thinkwood.com/en/permalink/catalogue544
Year of Publication
2016
Topic
Connections
Mechanical Properties
Material
CLT (Cross-Laminated Timber)
Author
Hossain, Afrin
Danzig, Ilana
Tannert, Thomas
Publisher
American Society of Civil Engineers
Year of Publication
2016
Format
Journal Article
Material
CLT (Cross-Laminated Timber)
Topic
Connections
Mechanical Properties
Keywords
Self-Tapping Screws
Shear Resistance Performance
Shear Connection
Quasi-Static
Reverse Cyclic Loading
Lateral Load
Research Status
Complete
Series
Journal of Structural Engineering
Summary
The research presented in this paper examines the shear resistance performance of self-tapping screws (STS) in three-ply cross-laminated timber (CLT) panels. Specifically, the feasibility of using innovative STS assemblies with double inclination of fasteners was investigated for the shear connection of CLT panels. The specimens (1.5×1.5 m) were subjected to quasi-static and reversed-cyclic loading. The tests were set up to approximate pure shear loading, with three-panel CLT assemblies connected with STS. The resulting load-displacement and hysteretic curves were used to determine an equivalent energy elastic-plastic curve to estimate assembly capacity, yield load, yield displacement, ductility ratio, stiffness, and damping. Excellent structural performance in terms of capacity and stiffness was obtained while still providing the required ductility for the system to be used in seismic applications. The average static and cyclic yield loads were 6.0 kN/screw and 5.9 kN/screw, respectively. Average static and cyclic and ductility ratios were 7.7 and 4.1, respectively, allowing the connection to be classified as highly ductile under quasi-static loading and moderately ductile under reversed cyclic loading. The data obtained allow engineers to specify an innovative connection assembly with double inclination of fasteners for lateral load–resisting systems of CLT structures.
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Cyclic Load Behaviour of Beam-to-Column Glulam Joints Combining Glued-in Rods with Steel Brackets

https://research.thinkwood.com/en/permalink/catalogue2028
Year of Publication
2018
Topic
Connections
Mechanical Properties
Material
Glulam (Glue-Laminated Timber)
Author
Ling, Zhibin
Liu, Weiqing
Yang, Huifeng
Xiang, Zhe
Year of Publication
2018
Format
Conference Paper
Material
Glulam (Glue-Laminated Timber)
Topic
Connections
Mechanical Properties
Keywords
Beam-to-Column
Joints
Glued-In Rods
Steel Brackets
Cyclic Loading
Monotonic Loading
Failure Modes
Stiffness
Ductility
Energy Dissipation
Hysteresis Loop
Douglas-Fir
Conference
World Conference on Timber Engineering
Research Status
Complete
Summary
This paper presents an experimental campaign conducted on the beam-to-column glulam joints combing glued-in rods and steel brackets (BCGS glulam joints) aiming to investigate the mechanical behaviour of these glulam joints under low cyclic loading. Three types of steel brackets were designed for connecting the beam and column combing with glued-in rods and to work as energy dissipaters. In each group of specimens (except for group MJ4), two specimens were tested under monotonic loading and the others were subjected to low cyclic loading. The test results were summarized comprehensively in terms of failure modes, joint stiffness, hysteresis loops, ductility and energy dissipation ability. Generally, the difference of load capacity between BCGS glulam joints and the beam-to-column glulam joints only with glued-in rods (BCG glulam joints) was not significant. The joint stiffness of BCG glulam joints was higher than that of the BCGS glulam joints, while the stiffness degradation of the later is slower than the former. The hysteresis loops of the BCGS glulam joints exhibited less pinching effect obviously compared with the BCG glulam joints, which indicated that the energy dissipation ability of the glulam joints with glued-in rods could be improved significantly by using the steel brackets as energy dissipaters. Moreover, it should be noted that the hysteresis loops of groups CJ1 showed slipping effect obviously during testing. This might due to the insufficient shear resistance of these two groups, so that further investigations on BCG glulam joints with shear-resisting components are urgently needed.
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Cyclic Testing and Simulation of Hold Down Connections in Radiata Pine CLT Shear Walls

https://research.thinkwood.com/en/permalink/catalogue1605
Year of Publication
2016
Topic
Connections
Mechanical Properties
Material
CLT (Cross-Laminated Timber)
Application
Shear Walls
Author
Benedetti, Franco
Rosales, Víctor
Opazo, Alexander
Year of Publication
2016
Format
Conference Paper
Material
CLT (Cross-Laminated Timber)
Application
Shear Walls
Topic
Connections
Mechanical Properties
Keywords
Pine
Hold-Down
Hysteretic Model
Cyclic Loading
Conference
World Conference on Timber Engineering
Research Status
Complete
Notes
August 22-25, 2016, Vienna, Austria p. 2041-2050
Summary
Structures built with cross laminated timber (CLT) are an attractive alternative to traditional construction materials in terms of environmental performance and habitability, but its structural behavior is not well understood for each timber specie. This work provides a comprehensive study of the structural behavior of radiata pine CLT shear walls, by means of laboratory testing and numerical analysis of hold down connections. The observed test response of connections is replicated by calibrating two hysteretic models on OpenSees, and its fidelity is revised through the analysis of a full scale wall test and simulation. Main outcomes suggest that advanced modelling tools can accurately reproduce the hysteretic behaviour of the connections of timber panels. In terms of connections behaviour, it is observed that hold downs on radiata pine CLT elements reach less load capacity than hold downs on other wood specie, and no significant difference with the parallel to grain capacity of angle brackets connections is noticed. Besides, it is found that radiata pine CLT walls can achieve suitable cyclic loading performance and reach high levels of displacement ductility. Furthermore, the importance of friction on the load capacity of the wall is showed.
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Cyclic Testing of Pre-engineered Beam-Hanger Connections & Reinforcement of Holes in Glulam Beams Using Self-tapping Screws

https://research.thinkwood.com/en/permalink/catalogue2518
Year of Publication
2020
Topic
Connections
Mechanical Properties
Application
Beams

Development of an inter-panel connector for cross-laminated timber rocking walls capable of reverse cyclic loading

https://research.thinkwood.com/en/permalink/catalogue2040
Year of Publication
2018
Topic
Seismic
Mechanical Properties
Material
CLT (Cross-Laminated Timber)
Application
Walls
Author
Morrell, Ian
Organization
Washington State University
Year of Publication
2018
Format
Thesis
Material
CLT (Cross-Laminated Timber)
Application
Walls
Topic
Seismic
Mechanical Properties
Keywords
Rocking Walls
Shear Fuse
Reverse Cyclic Loading
Dynamic Testing
Research Status
Complete
Summary
The objective of this research was to develop an inter-panel connector capable of sustaining reverse cyclic loads. The prescribed use for the connector was for cross-laminated timber rocking walls. Cross-laminated timber has few current lateral systems. From this need two shear plate inter-panel connectors were designed: A and B. These connectors had high initial stiffness and displacement capacity. The end goal was shake table testing the connectors on a two-story structure. First, finite element modeling was conducted to ensure connectors were sufficient for design. Panels were tested on two scales at Washington State. The first was a single connector level, which had some errors in boundary condition, which limited the output. Second, a rocking wall test, isolating the connectors. This test produced higher quality results, though some errors at high drifts occurred. Stiffness of A and B were 4 and 32 k/in, respectively. Both had equivalent viscous damping for isolated connectors in the range of 20%, however B was dropping to a lower converging value. Due to the buckling behavior of the fuses and connection details, an augmented Fuse A was the sole fuse on the shake table structure. Shake table testing was conducted on a full-scale two-story building at University of California, San Diego. 13 motions were run, ranging in scale from service level earthquakes to scaling higher than a maximum considered earthquake. Four separate records were used to ensure a wide range of frequencies and amplitudes. The connectors experienced less visible residual deformation than in the small tests and the test displacements were lower. The beginnings of lateral torsional buckling began after the last test, scaled above maximum considered earthquake. The period was high for a two-story structure, at approximately one second. The building underwent approximately four percent roof drift and the structure alone had an equivalent viscous damping of approximately 14%. From these two separate scaled tests, the next step was to determine a preliminary design process. This process involves selection of connectors for certain purposes and utilizing modeling and performance based design to ensure the connector is proper for the given lateral system.
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Ductile Cross Laminated Timber (CLT) Platform Structures with Passive Damping

https://research.thinkwood.com/en/permalink/catalogue1728
Year of Publication
2016
Topic
Seismic
Mechanical Properties
Material
CLT (Cross-Laminated Timber)
Application
Wood Building Systems
Author
Hashemi, Ashkan
Loo, Wei Yuen
Masoudnia, Reza
Zarnani, Pouyan
Quenneville, Pierre
Year of Publication
2016
Format
Conference Paper
Material
CLT (Cross-Laminated Timber)
Application
Wood Building Systems
Topic
Seismic
Mechanical Properties
Keywords
Low-Rise
Numerical Model
Reverse Cyclic Loading
Quasi-Static
Simulation
Strength
Slip
Platform Buildings
Conference
World Conference on Timber Engineering
Research Status
Complete
Notes
August 22-25, 2016, Vienna, Austria p. 4730-4737
Summary
Multi-storey platform cross laminated timber (CLT) structures are becoming progressively desirable for engineers and owners. This is because they offer many significant advantages such as speed of fabrication, ease of construction, and excellent strength to weight ratio. With platform construction, stories are fixed together in a way that each floor bears into load bearing walls, therewith creating a platform for the next level. The latest research findings have shown that CLT platform buildings constructed with traditional fasteners can experience a high level of damage especially in those cases where the walls have adopted hold-down brackets and shear connectors with nails, rivets or screws. Thus, the current construction method for platform CLT structures is less than ideal in terms of damage avoidance. The main objective of this study is to develop a low damage platform timber panelised structural system using a new configuration of slip friction devices in lieu of traditional connectors. A numerical model of such a system is developed for a low rise CLT building and then is subjected to reversed cyclic load simulations in order to investigate its seismic performance. The result of these quasi-static simulations demonstrated that the system maintained the strength through numerous cycles of loading and unloading. In addition to this, the system is capable of absorbing significant amount of energy. The findings of this study demonstrate the proposed concept has the potential to be developed as a low damage seismic solution for CLT platform buildings.
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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
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
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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37 records – page 1 of 4.