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19 records – page 1 of 2.

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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Carterton Events Centre Auditorium Pres-Lam Wall Design and Construction

https://research.thinkwood.com/en/permalink/catalogue38
Year of Publication
2012
Topic
Seismic
Material
LVL (Laminated Veneer Lumber)
Application
Wood Building Systems
Shear Walls
Author
Dekker, Dave
Chung, Stanley
Palermo, Alessandro
Year of Publication
2012
Format
Conference Paper
Material
LVL (Laminated Veneer Lumber)
Application
Wood Building Systems
Shear Walls
Topic
Seismic
Keywords
Lateral Loads
Post-Tensioned
Pres-Lam
Sustainability
Conference
New Zealand Society for Earthquake Engineering Conference
Research Status
Complete
Notes
April 13-15, 2012, Christchurch, New Zealand
Summary
Driven by sustainability, locally available resources and expertise, and economy, the design of the Carterton Events Centre focused on timber for the majority of the main structural and non-structural components. Combined with a client desire for minimization of earthquake damage, dissipative post-tensioned rocking...
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Cathedral Hill 2: Challenges in the Design of a Tall All-Timber Building

https://research.thinkwood.com/en/permalink/catalogue1660
Year of Publication
2016
Topic
Design and Systems
Seismic
Wind
Material
CLT (Cross-Laminated Timber)
LVL (Laminated Veneer Lumber)
Application
Wood Building Systems
Author
Below, Kevin
Sarti, Francesco
Year of Publication
2016
Format
Conference Paper
Material
CLT (Cross-Laminated Timber)
LVL (Laminated Veneer Lumber)
Application
Wood Building Systems
Topic
Design and Systems
Seismic
Wind
Keywords
Pres-Lam
Dynamic Behaviour
Nonlinear Time History Analysis
Wind Loading
Conference
World Conference on Timber Engineering
Research Status
Complete
Notes
August 22-25, 2016, Vienna, Austria p. 3633-3640
Summary
The paper presents the design and modelling of Cathedral Hill 2, a 15-storey timber building, planned for construction in Canada. The building is a 59-metre tall office-use construction with an all-timber structure where the lateral-load-resisting system consists of segmented Pres-Lam walls. The paper firstly presents the design philosophy, and the motivations for the use of the Pres-Lam system, which was mainly driven by serviceability limit-state wind loading. The final part of the paper shows the verification of the building’s dynamic behaviour using non-linear time-history analysis, showing that, although the lateral-load design is governed by serviceability limit-state wind deflections, earthquake demand must not be overlooked due to higher-mode amplifications.
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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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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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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 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 seismic response of a resilient 3-storey post-tensioned timber framed building with dissipative braces

https://research.thinkwood.com/en/permalink/catalogue2856
Year of Publication
2020
Topic
Seismic
Material
Glulam (Glue-Laminated Timber)
Application
Frames
Author
Cesare, Antonio Di
Ponzo, Felice Carlo
Lamarucciola, Nicla
Nigro, Domenico
Organization
University of Basilicata
Publisher
Springer
Year of Publication
2020
Format
Journal Article
Material
Glulam (Glue-Laminated Timber)
Application
Frames
Topic
Seismic
Keywords
Pres-Lam
Post-Tensioned Timber
Seismic Resilience
Dissipative Brace
Hysteretic Damper
Research Status
Complete
Series
Bulletin of Earthquake Engineering
Summary
With the increased number of multi-storey buildings in seismic areas, research efforts have been focused on developing earthquake resilient systems, such as low-damage techniques based on the combination of post-tensioning and dissipating devices. This paper describes the experimental study performed on a 3-storey post-tensioned timber framed (Pres-Lam) building equipped with energy dissipating systems. The testing project consisted of three phases adopting different configurations of the experimental model: (1) post-tensioning to beam-column joints only, (2) post-tensioning and dissipative rocking mechanisms and (3) post-tensioning and dissipative braces. The main objective of this paper is to experimentally investigate on the seismic response of a large-scale specimen with dissipative braces located in high seismic area, considering construction details similar to those adopted in practical applications. During the experimental campaign, the test frame was subjected to more than one hundred ground motions considering a set of seven spectra-compatible earthquakes at increasing intensity levels. The dissipating bracing system with external replaceable hysteretic dampers improves the seismic resilience of multi-storey Pres-Lam buildings, showing inter-storey drift comparable to those with rocking walls, with full recentring capability and without structural damages or post-tensioning losses through seismic tests.
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Floor Diaphragms in Multi-Storey Timber Buildings

https://research.thinkwood.com/en/permalink/catalogue71
Year of Publication
2016
Topic
Design and Systems
Seismic
Material
Light Frame (Lumber+Panels)
Glulam (Glue-Laminated Timber)
LVL (Laminated Veneer Lumber)
CLT (Cross-Laminated Timber)
Application
Floors
Author
Moroder, Daniel
Organization
University of Canterbury
Year of Publication
2016
Format
Thesis
Material
Light Frame (Lumber+Panels)
Glulam (Glue-Laminated Timber)
LVL (Laminated Veneer Lumber)
CLT (Cross-Laminated Timber)
Application
Floors
Topic
Design and Systems
Seismic
Keywords
Diaphragms
Lateral Loads
Multi-Storey
Equivalent Truss Method
Pres-Lam
Research Status
Complete
Summary
This thesis studies the behaviour of diaphragms in multi-storey timber buildings by providing methods for the estimation of the diaphragm force demand, developing an Equivalent Truss Method for the analysis of timber diaphragms, and experimentally investigating the effects of displacement incompatibilities between the diaphragm and the lateral load resisting system and developing methods for their mitigation. Although shortcomings in the estimation of force demand, and in the analysis and design of concrete floor diaphragms have already been partially addressed by other researchers, the behaviour of diaphragms in modern multi-storey timber buildings in general, and in low damage Pres-Lam buildings (consisting of post-tensioned timber members) in particular is still unknown. The analysis of light timber framing and massive timber diaphragms can be successfully analysed with an Equivalent Truss Method, which is calibrated by accounting for the panel shear and fastener stiffnesses. Finally, displacement incompatibilities in frame and wall structures can be accommodated by the flexibilities of the diaphragm panels and relative connections. A design recommendations chapter summarizes all findings and allows a designer to estimate diaphragm forces, to analyse the force path in timber diaphragms and to detail the connections to allow for displacement incompatibilities in multi-storey timber buildings.
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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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19 records – page 1 of 2.