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11 records – page 1 of 2.

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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Higher Mode Effects in Multi-Storey Timber Buildings with Varying Diaphragm Flexibility

https://research.thinkwood.com/en/permalink/catalogue1480
Year of Publication
2017
Topic
Seismic
Mechanical Properties
Material
CLT (Cross-Laminated Timber)
Application
Frames
Walls
Author
Moroder, Daniel
Sarti, Francesco
Pampanin, Stefano
Smith, Tobias
Buchanan, Andrew
Year of Publication
2017
Format
Conference Paper
Material
CLT (Cross-Laminated Timber)
Application
Frames
Walls
Topic
Seismic
Mechanical Properties
Keywords
Nonlinear Time History Analysis
Higher Mode Effects
Stiffness
Diaphragms
Inter-Story Drift
Conference
New Zealand Society for Earthquake Engineering Conference
Research Status
Complete
Notes
April 27-29, 2017, Wellington, New Zealand
Summary
With the increasing acceptance and popularity of multi-storey timber buildings up to 10 storeys and beyond, the influence of higher mode effects and diaphragm stiffness cannot be overlooked in design. Due to the lower stiffness of timber lateral load resisting systems compared with traditional construction materials, the effect of higher modes on the global dynamic behaviour can be more critical. The presence of flexible timber diaphragms creates additional vibration modes, which have the potential to interact with each other, increasing the seismic demand on the whole structure. This paper uses a parametric non-linear time-history analysis on a series of timber frame and wall structures with varying diaphragm flexibility to study their dynamic behaviour and to determine diaphragm forces. The analyses results showed that although higher mode effects play a significant role in the structural dynamic response, this increased demand can be successfully predicted with methods available in literature. The parametric analyses showed that the diaphragm flexibility did not significantly increase the shear and moment demand; however, stiff wall structures with flexible diaphragms experienced large inter-storey drifts measured at diaphragm midspan compared with the drift of the wall alone. As expected, the diaphragm forces observed from the time-history analyses were significantly higher than the forces derived from an equivalent static analysis, leading to a potentially unsafe design. The paper presents a simplified approach for evaluating these amplified peak inertial diaphragm forces.
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Long-term Dynamic Characteristics of Pres-Lam Structures

https://research.thinkwood.com/en/permalink/catalogue1647
Year of Publication
2016
Topic
Design and Systems
Seismic
Material
LVL (Laminated Veneer Lumber)
Application
Wood Building Systems
Author
Smith, Tobias
Sarti, Francesco
Granello, Gabriele
Marshall, Jack
Buckton-Wishart, Victoria
Li, Minghao
Palermo, Alessandro
Pampanin, Stefano
Year of Publication
2016
Format
Conference Paper
Material
LVL (Laminated Veneer Lumber)
Application
Wood Building Systems
Topic
Design and Systems
Seismic
Keywords
Pres-Lam
Long-term
Dynamic Behaviour
Conference
World Conference on Timber Engineering
Research Status
Complete
Notes
August 22-25, 2016, Vienna, Austria p. 3462-3470
Summary
Pres-Lam timber structures are being adopted throughout New Zealand and around the world. This innovative method of timber construction combines the use of large engineered timber members with posttensioning cables/bars. The hybrid version of the Pres-Lam system improves seismic performance through the addition of external or internal steel reinforcing. While the post-tensioning provides re-centering properties, the steel increases energy dissipation from the system as well as increasing moment resistance. The design of these structures is performed to withstand high levels of seismic loading without damage to the structural system. Over time, the post-tensioning force being applied to the structural timber members causes them to reduce in length that has a subsequent impact on the quantity of force being applied. This paper looks at the dynamic characteristics of fundamental period and elastic damping of three recently constructed Pres-Lam buildings, investigating the influence of these losses on the dynamic characteristics. Following this a study of the performance under strong motion is performed. The paper concludes that although the losses in post-tensioning are clear they do not impact on the dynamic characteristics and have only a minor impact on strong motion response.
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Pres-Lam in the US: The Seismic Design of the Peavy Building at Oregon State University

https://research.thinkwood.com/en/permalink/catalogue1475
Year of Publication
2017
Topic
Design and Systems
Mechanical Properties
Seismic
Material
CLT (Cross-Laminated Timber)
Glulam (Glue-Laminated Timber)
Timber-Concrete Composite
Application
Hybrid Building Systems
Author
Sarti, Francesco
Smith, Tobias
Danzig, Ilana
Karsh, Eric
Year of Publication
2017
Format
Conference Paper
Material
CLT (Cross-Laminated Timber)
Glulam (Glue-Laminated Timber)
Timber-Concrete Composite
Application
Hybrid Building Systems
Topic
Design and Systems
Mechanical Properties
Seismic
Keywords
Pres-Lam
Load Carrying Capacity
US
Codes
Nonlinear Time History Analysis
Conference
New Zealand Society for Earthquake Engineering Conference
Research Status
Complete
Notes
April 27-29, 2017, Wellington, New Zealand
Summary
Pres-Lam is a post-tensioned rocking timber technology that has been developed over the last decade at the University of Canterbury. Pres-Lam overcomes a major challenge in timber construction, the development of a high strength moment connection, by tying mass timber elements together with high-strength steel post-tensioned tendons. In seismic areas, additional reinforcing can be added to the system increasing capacity as well as providing hysteretic damping. In 2010 Pres-Lam moved from laboratory testing to onsite implementation and has now been used in the construction of numerous building in New Zealand and around the world. This paper will present the lateral load design of the first Pres-Lam structure to be built in the United States: the Peavy Building at Oregon State University, Corvallis, Oregon. Peavy is a three-storey mass timber building within the College of Forestry. A glulam and CLT gravity structure support the timber-concrete-composite floor, which is made up of CLT panels spanning between glulam beams. The lateral load carrying capacity is provided in the two orthogonal directions by Pres-Lam walls fabricated from Cross Laminated Timber (CLT). The paper will present an overview of the design philosophy and the main motivations for the use of the Pres-Lam system, discuss the requirements for U.S. code compliance, and review the nonlinear time-history analysis of the Pres-Lam structure.
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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
Format
Journal Article
Application
Walls
Topic
Connections
Seismic
Keywords
Post-Tensioning
Dissipation
Quasi-Static
Cyclic Tests
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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Quasi Static Cyclic Tests of 2/3 Scale Post-Tensioned Timber Wall and Column-Wall-Column (CWC) Systems

https://research.thinkwood.com/en/permalink/catalogue648
Year of Publication
2014
Topic
Seismic
Material
LVL (Laminated Veneer Lumber)
Application
Walls
Author
Sarti, Francesco
Palermo, Alessandro
Pampanin, Stefano
Year of Publication
2014
Format
Conference Paper
Material
LVL (Laminated Veneer Lumber)
Application
Walls
Topic
Seismic
Keywords
Post-Tensioned
Quasi-Static Testing
Column-Wall-Column
Steel
U-Shaped Flexural Plates
Displacement
Conference
New Zealand Society for Earthquake Engineering Conference
Research Status
Complete
Notes
March 21-23, 2014, Auckland, New Zealand
Summary
The paper presents the design and construction detailing of the quasi-static testing of two post-tensioned timber wall systems: a single (more traditional) wall system and a new configuration comprising of a column-wall-column coupled system (CWC). The latter allows avoiding displacement incompatibilities issues between the wall and the diaphragm by using the boundary columns as supports. Different reinforcement configurations were taken into account for both the wall systems; the walls were subjected to different initial post-tensioning stress levels, and different dissipater options were considered: both internal and external replaceable mild steel tension-compression yield fuses, and U-shape Flexural Plates (UFPs) were used for the single wall and the CWC solutions respectively. The experimental results showed the high-performance of both post-tensioned timber wall systems with negligible level of structural damage in the wall element and residual displacements and high level of dissipation.
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11 records – page 1 of 2.