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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.
Online Access
Free
Resource Link
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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.
Online Access
Free
Resource Link
Less detail