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Combination of laser scanner and drilling resistance tests to measure geometry change for structural assessment of timber beams exposed to fire

https://research.thinkwood.com/en/permalink/catalogue3057
Year of Publication
2021
Topic
Fire
Application
Beams
Author
Cabaleiro, Manuel
Suñer, Carlos
Sousa, Hélder S.
Branco, Jorge M.
Organization
University of Vigo
University of Minho
Publisher
Elsevier
Year of Publication
2021
Format
Journal Article
Application
Beams
Topic
Fire
Keywords
Drilling Resistance Test
Structural Assessment
Laser Scanning
Cloud Point
Research Status
Complete
Series
Journal of Building Engineering
Summary
A structure may be totally destroyed due to a fire, but often it is only partially damaged and parts of it may still be salvaged and reused. For buildings with significant historic and cultural value, it is of utmost importance that these elements, which were only partially damaged, can still be recovered as to preserve the authenticity of the structure. In the case of timber elements after a fire, it is common to find damage on the cross-section exterior part, whereas the inner part presents still a non-damaged section. Therefore, the element is often found with an exterior irregular shape, either due to its original shape prior decay or due to the exposure to fire, that does not coincide with the inner residual cross-section. Moreover, it is essential to perform a preliminary safety analysis to verify which elements can be preserved and to what extent interventions could be needed. The objective of this work is to apply a methodology that allows to calculate the residual cross-section of partially burnt timber elements structures as to calculate the resistant and apparent sections for geometry assessment and to implement that information in three-dimensional structural models. For this purpose, this work proposes a methodology based on a combination of drilling resistance tests together with laser scanner measurements. The methodology was first tested and calibrated within a controlled laboratory environment and then validated onsite using elements from a building exposed to a past fire. The Casa de Sarmento (Sarmento's House) in Guimarães (Portugal) was used as case study, where various structural damages due to a past fire were found.
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Numerical Analysis of Masonry-Infilled RC-CLT Panel Connections

https://research.thinkwood.com/en/permalink/catalogue3258
Year of Publication
2022
Topic
Mechanical Properties
Material
CLT (Cross-Laminated Timber)
Application
Frames
Author
Mehdipour, Zabih
Poletti, Elisa
Branco, Jorge M.
Lourenço, Paulo B.
Organization
University of Minho
Editor
Tullini, Nerio
Publisher
MDPI
Year of Publication
2022
Format
Journal Article
Material
CLT (Cross-Laminated Timber)
Application
Frames
Topic
Mechanical Properties
Keywords
RC-CLT Connectors
Optimum Arrangement of Connections
Masonry-infilled RC Frame
Research Status
Complete
Series
Buildings
Summary
CLT panels have been investigated for reinforcement of existing masonry-infilled RC framed buildings through the increase of the overall lateral stiffness of the structure, thus reducing the story drift demand. The contribution of CLT panels depends on the connection to the RC frame elements. This paper evaluates the role of connectors by which CLT is attached to RC frames for capacity, ductility, and energy dissipation of the structure and its elements separately using different kinds of RC-CLT connections, and ultimately finds and compares the optimum number and arrangement of connectors. The results show that the geometry of connections plays a greater seismic role in RC frames than their mechanical properties. Regarding masonry infills, they allow a higher strength capacity but reduce the efficacy of CLT strengthening. However, strong connectors decrease the ability of infills in dissipation. Finally, in the optimum arrangement of connectors, they are distributed equally along the upper and lower beams at equal spacing, where CLT is added, starting in the middle of the beams and moving to the frame corners.
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Free
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Statistical correlation investigation of a single-doweled timber-to-timber joint

https://research.thinkwood.com/en/permalink/catalogue3193
Year of Publication
2022
Topic
Connections
Author
Aquino, Caroline D.
Rodrigues, Leonardo G.
Branco, Jorge M.
Gomes, Wellison J.S.
Organization
University of Minho
Federal University of Santa Catarina
Publisher
Elsevier
Year of Publication
2022
Format
Journal Article
Topic
Connections
Keywords
Timber Joints
Uncertainty Quantification
Joint Behavior
Copula Theory
Reliability Analysis
Research Status
Complete
Series
Engineering Structures
Summary
Dowel-type joints are widely used in timber structures given their ease of construction, strength, and capacity to deform before failure. The embedment strength of timber and the bending moment capacity of dowels are considered key properties in the design. On the other hand, these properties have an inherent variability that increases the uncertainties related to the connection’s strength and associated failure modes. This study proposes to quantify the uncertainty related to the statistical correlation behavior between the timber embedment strength and dowel bending moment capacity while comparing analytical solutions to the results of double shear single doweled timber joints. Traditional distribution fitting procedures, as well as copula functions, are implemented to capture their marginal and dependence behavior. Since their source of mutual correlation is known, the effectiveness of the different approaches in describing the statistical dependence structure can be assessed. This is done by investigating how equivalent are the descriptions of dependence by copula functions and directly from the correlation origin. Results obtained here indicate that, for single dowel-type connections in double shear, the impact of the copulas on the results is small, which means that improving their joint characterization represents a minor improvement in the reliability results. Besides the minor differences, the results show that copula functions are a viable tool capable of capturing the nuances of the joint behavior between random variables.
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