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35 records – page 1 of 4.

An Equivalent Truss Method for the Analysis of Timber Diaphragms

https://research.thinkwood.com/en/permalink/catalogue112
Year of Publication
2015
Topic
Design and Systems
Mechanical Properties
Material
Light Frame (Lumber+Panels)
CLT (Cross-Laminated Timber)
LVL (Laminated Veneer Lumber)
Glulam (Glue-Laminated Timber)
Application
Floors
Author
Moroder, Daniel
Smith, Tobias
Pampanin, Stefano
Buchanan, Andrew
Year of Publication
2015
Format
Conference Paper
Material
Light Frame (Lumber+Panels)
CLT (Cross-Laminated Timber)
LVL (Laminated Veneer Lumber)
Glulam (Glue-Laminated Timber)
Application
Floors
Topic
Design and Systems
Mechanical Properties
Keywords
Diaphragms
Equivalent Truss Method
Fasteners
Forces
Deflection
Torsion
Conference
Pacific Conference on Earthquake Engineering
Research Status
Complete
Notes
November 6-8, 2015, Sydney, Australia
Summary
Recent years have seen more architects and clients asking for tall timber buildings. In response, an ambitious timber community has been proposing challenging plans and ideas for multi-storey commercial and residential timber buildings. While engineers have been intensively looking at gravity-load-carrying elements as well as walls, frames and cores to resist lateral loads, floor diaphragms have been largely neglected. Complex floor geometries and long span floor diaphragms create stress concentrations, high force demand and potentially large deformations. There is a lack of guidance and regulation regarding the analysis and design of timber diaphragms so structural engineers need a practical alternative to simplistic equivalent deep beam analysis or costly finite element modelling. This paper proposes an equivalent truss method capable of solving complex geometries for both light timber framing and massive timber diaphragms. Floor panels are discretized by equivalent diagonals, having the same stiffness as the panel including its fasteners. With this method the panel unit shear forces (shear flow) and therefore fastener demand, chord forces and reaction forces can be evaluated. Because panel stiffness is accounted for, diaphragm deflection, torsional effects and transfer forces can also be assessed.
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Design and Construction of Prestressed Timber Buildings for Seismic Areas

https://research.thinkwood.com/en/permalink/catalogue1847
Year of Publication
2018
Topic
Design and Systems
Material
LVL (Laminated Veneer Lumber)
Glulam (Glue-Laminated Timber)
Application
Wood Building Systems
Author
Smith, Tobias
Pampanin, Stefano
Fragiacomo, Massimo
Buchannan, Andy
Publisher
New Zealand Timber Design Society
Year of Publication
2018
Format
Journal Article
Material
LVL (Laminated Veneer Lumber)
Glulam (Glue-Laminated Timber)
Application
Wood Building Systems
Topic
Design and Systems
Keywords
Pre-Stressed
Low-Rise
Multi-Storey
Earthquake Resistance
Hybrid Structures
Research Status
Complete
Series
New Zealand Timber Design Journal
Summary
This paper describes the structural design of low-rise multi-storey timber buildings using a new and exciting structural system. This system, originally developed for use with pre-cast concrete, combines un-bonded post-tensioning and additional energy dissipaters, providing a recentering capability after the earthquake, while greatly reducing the structural damage. This new structural system can be used in multi-storey buildings, with large structural timber members made from laminated veneer lumber (LVL) or glulam timber, with lateral loads resisted by prestressed timber frames or walls, separately or in combination. A case study of a six storey timber office building in a moderate seismic area is analysed and a virtual design is carried out, allowing investigation of different methods of structural analysis, and development of many construction and connection details for rapid construction. Total building cost is compared to equivalent steel and reinforced concrete options.
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Design and Testing of Post-Tensioned Timber Wall Systems

https://research.thinkwood.com/en/permalink/catalogue696
Year of Publication
2014
Topic
Design and Systems
Seismic
Material
Glulam (Glue-Laminated Timber)
LVL (Laminated Veneer Lumber)
Application
Walls
Author
Sarti, Francesco
Palermo, Alessandro
Pampanin, Stefano
Year of Publication
2014
Format
Conference Paper
Material
Glulam (Glue-Laminated Timber)
LVL (Laminated Veneer Lumber)
Application
Walls
Topic
Design and Systems
Seismic
Keywords
Multi-Storey
Pres-Lam
Energy Dissipation
Quasi-Static Test
Conference
World Conference on Timber Engineering
Research Status
Complete
Notes
August 10-14, 2014, Quebec City, Canada
Summary
The paper presents the design and detailing, and the experimental quasi-static 2/3 scale tests of two posttensioned wall systems: a single (more traditional) wall system (Figure 2) and a new configuration comprising of a column-wall-column coupled system (Figure 3). The latter allows avoiding displacement incompatibilities issues between the wall and the diaphragm by using the boundary columns as supports.
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Design of Floor Diaphragms in Multi-Storey Timber Buildings

https://research.thinkwood.com/en/permalink/catalogue294
Year of Publication
2015
Topic
Design and Systems
Seismic
Material
CLT (Cross-Laminated Timber)
Light Frame (Lumber+Panels)
Application
Floors
Author
Moroder, Daniel
Smith, Tobias
Pampanin, Stefano
Palermo, Alessandro
Buchanan, Andrew
Year of Publication
2015
Format
Conference Paper
Material
CLT (Cross-Laminated Timber)
Light Frame (Lumber+Panels)
Application
Floors
Topic
Design and Systems
Seismic
Keywords
Diaphragms
Multi-Storey
Commercial
Lateral Loads
Equivalent Truss Method
Lateral Load Resisting System
Conference
New Zealand Society for Earthquake Engineering Conference
Research Status
Complete
Notes
April 10-12, 2015, Rotorua, New Zealand
Summary
This paper discusses the design of timber diaphragms, in response to the growing interest in multi-storey commercial timber structures, and the lack of guidance or regulations regarding the seismic design of timber diaphragms. Proper performance of floor diaphragms is required to transfer all lateral loads to the vertical systems that resist them, but design for earthquake loads can be more complex than design for wind loads. This paper confirms that the seismic design of a diaphragm is intimately linked to the seismic design of the whole building. Diaphragm failure, even if restricted to a limited diaphragm portion, can compromise the behaviour of the whole building. It is therefore necessary to design and detail diaphragms for all possible load paths and to evaluate their influence on the load distribution within the rest of the structure. It is strongly recommended that timber diaphragms be designed as elastic elements, by applying dynamic amplification and overstrength factors derived from the lateral load resisting system. This paper shows that some current design recommendations for plywood sheathing on light timber framing can be applied to massive wood diaphragms, but for more complex floor geometries an equivalent truss method is suggested. Diaphragm flexibility and displacement incompatibilities between the floor diaphragms and the lateral resisting systems also need to be accounted for.
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Development and Testing of an Alternative Dissipative Posttensioned Rocking Timber Wall with Boundary Columns

https://research.thinkwood.com/en/permalink/catalogue1884
Year of Publication
2016
Topic
Seismic
Design and Systems
Application
Frames
Walls
Author
Sarti, Francesco
Palermo, Alessandro
Pampanin, Stefano
Publisher
American Society of Civil Engineers
Year of Publication
2016
Format
Journal Article
Application
Frames
Walls
Topic
Seismic
Design and Systems
Keywords
Pres-Lam
Prestress
Post-Tensioning
Displacement
Seismic Performance
Column-Wall-Column
Research Status
Complete
Series
Journal of Structural Engineering
Summary
The unbonded post-tensioned rocking and dissipative technology was first developed as the main outcome of the PRESSS (PREcast Seismic Structural Systems) Program in US. After the first developments and significant refinement, the technology was extended to steel and, more recently, timber structures. The timber version, referred to as Pres-Lam (Prestressed laminated) system can be either implemented for timber walls (single or coupled) or frames or combination of the above, with unbonded post-tensioning and supplemental dissipation devices. In unbonded post-tensioned dissipative wall systems a combination of re-centering capacity and energy dissipation leads to a “controlled rocking” mechanism which develops a gap opening at the wall base. This generates an uplift displacement which is transferred to the floor diaphragm. This vertical displacement incompatibility can represent a potential issue if the connection detailing between floor and lateral resisting system is not designed properly. The same issue can be mitigated by adopting an alternative configuration of the rocking/dissipative wall system, based on the use of a column-wall-column post-tensioned connection. This concept, originally proposed for precast concrete walls and referred to as PreWEC (Prestressed Wall with End Column), has been extended and adapted to posttensioned timber structures and validated through experimental testing. The paper presents the design, detailing and experimental testing of a two-thirds scale wall specimen of this alternative configuration. Different wall configurations are considered in terms of post-tensioning initial force as well as dissipation devices layout. The experimental results confirm the excellent seismic performance of the system with the possibility to adopt multiple alternative configurations.
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Dynamic Testing of Multi-Storey Post-Tensioned Glulam Building: Planning, Design and Numerical Analysis

https://research.thinkwood.com/en/permalink/catalogue634
Year of Publication
2012
Topic
Design and Systems
Material
Glulam (Glue-Laminated Timber)
Application
Wood Building Systems
Author
Smith, Tobias
Pampanin, Stefano
Carradine, David
Di Cesare, Antonio
Carlo Ponzo, Felice
Auletta, Gianluca
Nigro, Domenico
Simonetti, Michele
Mossucca, Antonello
Year of Publication
2012
Format
Conference Paper
Material
Glulam (Glue-Laminated Timber)
Application
Wood Building Systems
Topic
Design and Systems
Keywords
Post-Tensioned
Dissipative Steel Angles
Dynamic Testing
Damping Ratio
Conference
World Conference on Earthquake Engineering
Research Status
Complete
Notes
September 24-28, 2012, Lisbon, Portugal
Summary
The following paper describes the first stage of dynamic testing of a post-tensioned timber building to be performed in the structural laboratory of the University of Basilicata in Potenza, Italy as part of a series of experimental tests in collaboration with the University of Canterbury in Christchurch, New Zealand. During this stage of testing a 3-dimensional, 3-storey post-tensioned timber structure will be tested. The specimen is 2/3rd scale and made up of frames in both directions composed of post-tensioned timber. The specimen will be tested both with and without the addition of dissipative steel angles which are designed to yield at a certain level drift. These steel angles release energy through hysteresis during movement thus increasing damping. The following paper discusses the testing set-up and preliminary numerical predictions of the system performance. Focus will be placed on damping ratios, displacements and accelerations.
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Evaluation of the Seismic Performance Factors Of Post-Tensioned Timber Wall Systems

https://research.thinkwood.com/en/permalink/catalogue80
Year of Publication
2014
Topic
Seismic
Material
LVL (Laminated Veneer Lumber)
Application
Walls
Author
Sarti, Francesco
Palermo, Alessandro
Pampanin, Stefano
Berman, Jeffrey
Organization
The European Association for Earthquake Engineering
Year of Publication
2014
Format
Conference Paper
Material
LVL (Laminated Veneer Lumber)
Application
Walls
Topic
Seismic
Keywords
Connections
Hybrid
Post-Tensioned
Pres-Lam
Testing
Conference
Second European Conference on Earthquake Engineering and Seismology
Research Status
Complete
Notes
August 25-29, 2014, Istanbul, Turkey
Summary
Low-damage seismic-resistant post-tensioning technologies were first developed during the PREcast Seismic Structural Systems program, coordinated by the University of California San Diego. Different connections were developed and tested as part of the research program, and the most stable solution was the hybrid connection, which provides a combination of re-centering and dissipative contributions. The hybrid connection was later extended to Laminated Veneer Lumber Elements (LVL) and referred to as Pres-Lam (Prestressed Laminated) system. As part of a broader experimental campaign on frame and walls systems, several experimental tests were carried out on small-scale specimens of post-tensioned single walls and on coupled walls systems. More recently 2/3 scale quasistatic tests were performed on different wall configurations. The paper shows the evaulation of the seismic performance factors of post-tensioned timber wall systems, carried out according to the FEMA P695 procedure. The latter utilizes nonlinear analysis techniques, and explicitly considers uncertainties in ground motion, modelling, design, and test data. The technical approach is a combination of traditional code concepts, advanced nonlinear dynamic analyses, and risk-based assessment techniques. A set of archetype buildings were developed to characterize the behaviour of the system. Several parameters were accounted for, such as the building height, lateral load resisting system, magnitude of the gravity loads and seismic design category. The system archetypes were represented by numerical models developed to simulate the full range of behavioural aspects of the system. Nonlinear quasi-static and dynamic analyses were carried out to determine the system over-strength factors and median collapse capacity of the buildings. The system performance was then assessed by computing the Collapse Margin Ratio (CMR) defined as the ratio of the median collapse (SCT) and MCE (SMT) spectral accelerations.Once the non-linear analysis results confirmed the CMR values were within acceptable values, the trial value of the seismic response modification, R, was confirmed, and the system seismic performance factors were evaluated.
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Experimental Behaviour of Diaphragms in Post-Tensioned Timber Frame Buildings

https://research.thinkwood.com/en/permalink/catalogue95
Year of Publication
2014
Topic
Connections
Seismic
Material
LVL (Laminated Veneer Lumber)
Application
Floors
Author
Moroder, Daniel
Smith, Tobias
Simonetti, Michele
Carlo Ponzo, Felice
Di Cesare, Antonio
Nigro, Domenico
Pampanin, Stefano
Buchanan, Andrew
Organization
The European Association for Earthquake Engineering
Year of Publication
2014
Format
Conference Paper
Material
LVL (Laminated Veneer Lumber)
Application
Floors
Topic
Connections
Seismic
Keywords
Diaphragms
Lateral Loads
Post-Tensioning
Shake Table Test
Testing
Conference
Second European Conference on Earthquake Engineering and Seismology
Research Status
Complete
Notes
August 25-29, 2014, Istanbul, Turkey
Summary
Floor diaphragms have an important role in the seismic behaviour of structures, as inertia forces are generated by their masses and then transferred to the lateral load resisting system. Diaphragms also link all other structural elements together and provide general stability to the structure. As with most other structural components, there is concern about damage to floor diaphragms because of displacement incompatibilities. This paper describes two different experiments on engineered timber floors connected to post-tensioned timber frames subjected to horizontal loading. First a full scale two-bay post-tensioned frame was loaded with lateral loads through a stressed-skin floor diaphragm. Different connection configurations between the floor units on either side of the central column were tested. Secondly a three dimensional, three storey post-tensioned frame building was tested on a shaking table. The diaphragm consisted of solid timber panels connected to the beams with inclined fully threaded screws. For all tested connections, the diaphragm behaviour was fully maintained throughout the testing and no damage was observed. The test results showed that careful detailing of the floor panel connections near the beam-columnjoint and the flexibility of timber elements can avoid floor damage and still guarantee diaphragm action at high level of drifts in post-tensioned timber frame buildings.
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Experimental Investigation of Wall-To-Floor Connections in Post-Tensioned Timber Buildings

https://research.thinkwood.com/en/permalink/catalogue60
Year of Publication
2014
Topic
Connections
Seismic
Material
LVL (Laminated Veneer Lumber)
Application
Walls
Floors
Author
Moroder, Daniel
Sarti, Francesco
Palermo, Alessandro
Pampanin, Stefano
Buchanan, Andrew
Year of Publication
2014
Format
Conference Paper
Material
LVL (Laminated Veneer Lumber)
Application
Walls
Floors
Topic
Connections
Seismic
Keywords
Connections
Damage
Lateral Loads
Post-Tensioned
Pres-Lam
Conference
New Zealand Society for Earthquake Engineering Conference
Research Status
Complete
Notes
March 21-23, 2014, Auckland, New Zealand
Summary
Rocking timber walls provide an excellent lateral load resisting system for structures using the low damage seismic design philosophy. Special attention has to be given to the wall-to-floor connections, because diaphragm forces have to be properly transferred while accommodating displacement incompatibilities, which include the relative rotation and the uplift of the wall with respect to the floor. This paper presents the experimental behaviour of several different wall-to-floor connections in Pres-Lam post-tensioned timber structures subjected to horizontal seismic loading. A 2/3 scale post-tensioned timber wall was laterally loaded through collector beams using different connection details. Bolted connections take advantage of the flexibility of the fasteners and lead to some bending of the collector beam, whereas pins and slotted steel plates reduce the wall-tofloor interaction, as they allow for rotation and some uplift. No significant damage to the floors was observed in any of the tests. The experimental results showed that floor damage can generally be prevented up to high levels of drift by the flexibility of well-designed connections and the flexibility of the collector beams. In the case of very stiff floors or very stiff collector beams, a more sophisticated connection such as sliding steel elements with a vertical slot should be considered.
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Experimental Investigations of Post-Tensioned Timber Frames with Advanced Seismic Damping Systems

https://research.thinkwood.com/en/permalink/catalogue464
Year of Publication
2012
Topic
Mechanical Properties
Seismic
Material
Glulam (Glue-Laminated Timber)
LVL (Laminated Veneer Lumber)
Application
Wood Building Systems
Author
Smith, Tobias
Carradine, David
Di Cesare, Antonio
Carlo Ponzo, Felice
Pampanin, Stefano
Buchanan, Andrew
Nigro, Domenico
Organization
Structures Congress
Publisher
American Society of Civil Engineers
Year of Publication
2012
Format
Conference Paper
Material
Glulam (Glue-Laminated Timber)
LVL (Laminated Veneer Lumber)
Application
Wood Building Systems
Topic
Mechanical Properties
Seismic
Keywords
Damping
Energy Dissipation
Full Scale
Post-Tensioning
Conference
Structures Congress 2012
Research Status
Complete
Notes
March 29-31, 2012, Chicago, Illinois, United States
Summary
This paper describes initial experimental testing to investigate feasible sources of passive damping for the seismic design of post-tensioned glue laminated timber structures. These innovative high performance structural systems extend precast concrete PRESSS technology to engineered wood structures, combining the use of post-tensioning bars or cables with large post-tensioned timber members. The combination of these two elements provides elastic recentering to the structure while the addition of damping using a specialised energy dissipation system gives the desirable `flag shaped' hysteretic response under lateral loading. Testing has been performed on a full scale beam-column joint at the University of Basilicata in Italy in a collaborative project with the University of Canterbury, New Zealand. The experimental testing uses engineered wood products, extending the use of laminated veneer lumber (LVL) structures tested in New Zealand to testing of glue laminated timber (glulam) structures in Italy. Current testing is aimed at further improvement of the system through additional energy dissipation systems.
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35 records – page 1 of 4.