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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
Country of Publication
Canada
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
Language
English
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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Experimental Study on Innovative Connections for Large Span Timber Truss Structures

https://research.thinkwood.com/en/permalink/catalogue47
Year of Publication
2015
Topic
Connections
Mechanical Properties
Material
Glulam (Glue-Laminated Timber)
Application
Beams
Author
Yang, Huifeng
Crocetti, Roberto
Larsson, Gustaf
Gustafsson, Per-Johan
Publisher
International Association for Shell and Spatial Structures (IASS)
Year of Publication
2015
Country of Publication
Japan
Format
Conference Paper
Material
Glulam (Glue-Laminated Timber)
Application
Beams
Topic
Connections
Mechanical Properties
Keywords
Reinforcement
Single Large Diameter Dowel Connection (SCDDC)
Full Scale
Tensile Tests
Quasi-Static
Steel Plates
Language
English
Conference
IASS WORKING GROUPS 12 + 18 International Colloquium 2015
Research Status
Complete
Notes
April 10-13, 2015, Tokyo, Japan
Summary
This paper summarizes an experimental investigation on several innovative reinforcing techniques for the “Single Large Diameter Dowel Connection”, SLDDC in timber truss structures. Besides lateral reinforcing or prestressing, also steel plates glued on two sides of the glulam specimens were used as reinforcing measure. To study the efficiency of these techniques, 15 full-scale quasi-static tensile tests on glulam members with a SLDDC on either ends of each member were performed. It was found that the reinforcement significantly enhanced the bearing capacity of the SLDDCs. All of the reinforcing techniques showed a satisfactory efficiency, preventing splitting of wood. Moreover, most of the specimens remains showed a remarkable post failure strength.
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Quasi-Static Cyclic Testing of Two-Thirds Scale Unbonded Posttensioned Rocking Dissipative Timber Walls

https://research.thinkwood.com/en/permalink/catalogue581
Year of Publication
2015
Topic
Connections
Seismic
Application
Walls
Author
Sarti, Francesco
Palermo, Alessandro
Pampanin, Stefano
Publisher
American Society of Civil Engineers
Year of Publication
2015
Country of Publication
United States
Format
Journal Article
Application
Walls
Topic
Connections
Seismic
Keywords
Post-Tensioning
Dissipation
Quasi-Static
Cyclic Tests
Language
English
Research Status
Complete
Series
Journal of Structural Engineering
Summary
Previous tests carried out on post-tensioned timber walls focused on small scale (one-third) specimens with the main objective of evaluating the general response of the system. The main objective of the experimental program herein presented is the testing and estimating of the response of a series two-third scale post-tensioned walls, with alternative arrangements and combination of dissipaters and post-tensioning, focusing on the construction details adopted in real practice. The paper first presents a brief discussion on the seismic demand evaluation based on the Displacement-Based Design approach. The construction detailing of the steel dissipater connections, post-tensioning anchorage and shear keys are then presented. The main objectives of the experimental program were the investigation of the experimental behaviour of large scale post-tensioned timber walls, with particular focus on the system connection detailing and optimization of post-tensioning anchorage, fastening of the dissipation devices and shear keys. The program consisted of several quasi-static cyclic tests considering different steel dissipater configurations, different levels of post-tensioning initial stress and different dissipater options were considered: both internal and external mild steel tension-compression yield devices were used. The experimental results showed the performance of post-tensioned timber wall systems which provide high level of dissipation while showing negligible residual displacements and negligible damage to the wall element. The final part of the paper presents the experimental evaluation of the area-based hysteretic damping for the tested specimens and the results highlight the great influence of the connection detailing of the dissipaters.
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Seismic Design and Testing of Rocking Cross Laminated Timber Walls

https://research.thinkwood.com/en/permalink/catalogue202
Year of Publication
2015
Topic
Design and Systems
Seismic
Material
CLT (Cross-Laminated Timber)
Application
Walls
Wood Building Systems
Author
Ganey, Ryan
Organization
University of Washington
Year of Publication
2015
Country of Publication
United States
Format
Thesis
Material
CLT (Cross-Laminated Timber)
Application
Walls
Wood Building Systems
Topic
Design and Systems
Seismic
Keywords
Diaphragms
Post-Tensioned
U-Shaped Flexural Plates
Energy Dissipation
Quasi-Static
Reverse Cyclic Load
Tall Wood
Language
English
Research Status
Complete
Summary
Seismically resilient, lateral systems for tall timber buildings can be created by combining cross laminated timber (CLT) panels with post-tensioned (PT) self-centering technology. The concept features a system of stacked CLT walls where particular stories are equipped to rock against the above and below floor diaphragms through PT connections and are supplemented with mild steel U-shaped flexural plate energy dissipation devices (UFPs). Experiments were conducted to better understand rocking CLT wall behavior and seismic performance. The testing program consisted of five single wall tests with varying PT areas, initial tensioning force, CLT panel composition, and rocking surface and one coupled wall test with UFPs as the coupling devices. The walls were tested with a quasi-static reverse-cyclic load protocol. The experimental results showed a ductile response and good energy dissipation qualities. To evaluate the feasibility and performance of the rocking CLT wall system, prototype designs were developed for 8 to 14 story buildings in Seattle using a performance-based seismic design procedure. Performance was assessed using numerical simulations performed in OpenSees for ground motions representing a range of seismic hazards. The results were used to validate the performance-based seismic design procedure for tall timber buildings with rocking CLT walls.
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Shear Connections with Self-Tapping-Screws for Cross-Laminated-Timber Panels

https://research.thinkwood.com/en/permalink/catalogue432
Year of Publication
2015
Topic
Connections
Mechanical Properties
Material
CLT (Cross-Laminated Timber)
Application
Wood Building Systems
Author
Hossain, Afrin
Lakshman, Ruthwik
Tannert, Thomas
Organization
Structures Congress
Publisher
American Society of Civil Engineers
Year of Publication
2015
Country of Publication
United States
Format
Conference Paper
Material
CLT (Cross-Laminated Timber)
Application
Wood Building Systems
Topic
Connections
Mechanical Properties
Keywords
Ductility
Self-Tapping Screws
Stiffness
Strength
Vertical Shear Loading
Mid-Scale
Quasi-Static
Shear Tests
Language
English
Conference
Structures Congress 2015
Research Status
Complete
Notes
April 23–25, 2015, Portland, Oregon, USA
Summary
Cross-Laminated-Timber (CLT) is increasingly gaining popularity in residential and non-residential applications in North America. To use CLT as lateral load resisting system, individual panels need to be connected. In order to provide in-plane shear connections, CLT panels may be joined with a variety of options including the use of self-tapping-screws (STS) in surface splines and half-lap joints. Alternatively, STS can be installed at an angle to the plane allowing for simple butt joints and avoiding any machining. This study investigated the performance of CLT panel assemblies connected with STS under vertical shear loading. The three aforementioned options were applied to join 3ply and 5-ply CLT panels. A total of 60 mid-scale quasi-static shear tests were performed to determine and compare the connection performance in terms of strength, stiffness, and ductility. It was shown that – depending on the screw layout – either very stiff or very ductile joint performance can be achieved.
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Structural and Thermal Behaviour of a Timber-Concrete Prefabricated Composite Wall System

https://research.thinkwood.com/en/permalink/catalogue247
Year of Publication
2015
Topic
Design and Systems
Mechanical Properties
Material
Glulam (Glue-Laminated Timber)
Timber-Concrete Composite
Application
Walls
Author
Destro, Riccardo
Boscato, Giosuè
Mazzali, Ugo
Russo, Salvatore
Peron, Fabio
Romagnoni, Piercarlo
Publisher
ScienceDirect
Year of Publication
2015
Country of Publication
Netherlands
Format
Journal Article
Material
Glulam (Glue-Laminated Timber)
Timber-Concrete Composite
Application
Walls
Topic
Design and Systems
Mechanical Properties
Keywords
Structural Behaviour
Thermal Behaviour
Prefabrication
Quasi-Static
In-Plane Tests
Language
English
Research Status
Complete
Series
Energy Procedia
Summary
This paper presents the analysis of the structural and thermal behaviour of an timber-concrete prefabricated composite wall system, the Concrete Glulam Framed Panel (CGFP) which is a panel made of a concrete slab and a structural glulam frame. The research analyses the structural performance with quasi-static in-plane tests, focused on the in-plane strength and stiffness of individual panels, and the thermal behaviour of the system with steady state tests using an hot box apparatus. The results validate the efficacy of proposed system ensuring the resistance and the dissipative structural behaviour through the hierarchy response characterized by the wood frame, the braced reinforced concrete panel of the singular module and by the rocking effects of global system.
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6 records – page 1 of 1.