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Feasibility of portable NIR spectrometer for quality assurance in glue-laminated timber production

https://research.thinkwood.com/en/permalink/catalogue2962
Year of Publication
2021
Topic
Mechanical Properties
Material
Glulam (Glue-Laminated Timber)
Author
Sandak, Jakub
Niemz, Peter
Hänsel, Andreas
Mai, Juana
Sandak, Anna
Organization
University of Primorska
ETH Zurich
Bern University of Applied Sciences
Luleå University of Technology
Saxon University of Cooperative Education
Publisher
Elsevier
Year of Publication
2021
Format
Journal Article
Material
Glulam (Glue-Laminated Timber)
Topic
Mechanical Properties
Keywords
Near Infrared Spectroscopy
Delamination
Quality Assurance
Research Status
Complete
Series
Construction and Building Materials
Summary
The feasibility of a portable NIR sensor for off-line determination of diverse wood quality aspects relevant in the production of glue-laminated timber was demonstrated. The best performance was noticed for assessing wood moisture content, with a lower capacity to estimate wood density and mechanical properties. NIR spectroscopy was modestly capable of predicting surface roughness. However, the traceability of the raw resources and the automatic classification of diverse wood defects were successfully demonstrated. The developed chemometric model could predict the total delamination and detailed delamination length. Finally, recommendations regarding further system development were provided with the aim of implementation and integration of the NIR measurement into glue-laminated timber production plants.
Online Access
Free
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Leveraging Structural Health Monitoring Data Through Avatars to Extend the Service Life of Mass Timber Buildings

https://research.thinkwood.com/en/permalink/catalogue3085
Year of Publication
2022
Author
Riggio, Mariapaola
Mrissa, Michael
Krész, Miklós
Vcelák, Jan
Sandak, Jakub
Sandak, Anna
Organization
Oregon State University
University of Primorska
University of Szeged
Czech Technical University in Prague
Year of Publication
2022
Format
Journal Article
Keywords
Mass Timber Building
Hygrothermal Monitoring
Avatars
Microclimate Data
Mold Risk Models
Research Status
Complete
Series
Frontiers in Built Environment
Summary
Mass timber construction systems, incorporating engineered wood products as structural elements, are gaining acceptance as a sustainable alternative to multi-story concrete or steel-frame structures. The relative novelty of these systems brings uncertainties on whether these buildings perform long-term as expected. Consequently, several structural health monitoring (SHM) projects have recently emerged to document their behavior. A wide and systematic use of this data by the mass timber industry is currently hindered by limitations of SHM programs. These limitations include scalability, difficulty of data integration, diverse strategies for data collection, scarcity of relevant data, complexity of data analysis, and limited usability of predictive tools. This perspective paper envisions the use of avatars as a Web-based layer on top of sensing devices to support SHM data and protocol interoperability, analysis, and reasoning capability and to improve life cycle management of mass timber buildings. The proposed approach supports robustness, high level and large-scale interoperability and data processing by leveraging the Web protocol stack, overcoming many limitations of conventional centralized SHM systems. The design of avatars is applied in an exemplary scenario of hygrothermal data reconstruction, and use of this data to compare different mold growth prediction models. The proposed approach demonstrates the ability of avatars to efficiently filter and enrich data from heterogeneous sensors, thus overcoming problems due to data gaps or insufficient spatial distribution of sensors. In addition, the designed avatars can provide prediction or reasoning capability about the building, thus acting as a digital twin solution to support building lifecycle management.
Online Access
Free
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Mechanical performance of timber connections made of thick flexible polyurethane adhesives

https://research.thinkwood.com/en/permalink/catalogue3130
Year of Publication
2021
Topic
Connections
Author
Pecnik, Jaka Gašper
Gavric, Igor
Sebera, Václav
Kržan, Meta
Kwiecien, Arkadiusz
Zajac, Boguslaw
Azinovic, Boris
Organization
University of Primorska
Slovenian National Building and Civil Engineering Institute
Cracow University of Technology
Publisher
Elsevier
Year of Publication
2021
Format
Journal Article
Topic
Connections
Keywords
Flexible Adhesive
Timber Connection
Polyurethane
Double Lap-shear
Cyclic Loading
Energy Dissipation
Research Status
Complete
Series
Engineering Structures
Summary
This study investigates timber connections with flexible polyurethane adhesives, which prove to have the potential for timber-adhesive composite structures without mechanical connections for seismic regions. Results of conducted cyclic double lap-shear adhesive timber joints tests were compared with available experimental results on timber connections with standard mechanical dowel-type fasteners and with results of numerical finite element analysis. The study found that the shear strength, elastic stiffness and strength degradation capacity of the flexible adhesive connections were significantly higher compared to mechanical fasteners commonly used in seismic-resistant timber connections. The latter, however, manifested larger ultimate displacements but also yielded at lower displacements.
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Free
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On the distribution of internal forces in single-storey CLT symmetric shear-walls with openings

https://research.thinkwood.com/en/permalink/catalogue2850
Year of Publication
2021
Topic
Mechanical Properties
Material
CLT (Cross-Laminated Timber)
Application
Shear Walls
Author
Casagrande, Daniele
Fanti, Riccardo
Greco, Marco
Gavric, Igor
Polastri, Andrea
Organization
Institute of Bioeconomy - National Research Council of Italy
University of Trento
University of Primorska
Publisher
Elsevier
Year of Publication
2021
Format
Journal Article
Material
CLT (Cross-Laminated Timber)
Application
Shear Walls
Topic
Mechanical Properties
Keywords
Shear Walls
Openings
Stress Distribution
Finite Element Modeling
Research Status
Complete
Series
Structures
Summary
This paper presents a numerical and analytical study on single-storey cross-laminated timber (CLT) shear-walls with openings subjected to lateral loads. The main objective was to investigate the location and distribution of maximum values of axial and shear forces in relevant wall sections. The influence of parameters such as wall geometry (different sizes of wall openings, door openings, lintel/parapet lengths and heights, wall thickness) and different stiffness levels of mechanical anchors for CLT wall connection with floor/foundation were studied. Finite element (FE) parametric analyses were performed on a set of single-storey CLT shear-walls with door and window openings and were compared with analytical models for determination of internal forces. The importance of wall connections’ flexibility was identified, as the distribution of internal forces in walls with rigid and flexible anchors were considerably different. The obtained outcomes of this study provide a solid base for the next step, an experimental investigation of in-plane internal force distribution in CLT walls with openings, which will serve for further development of numerical, analytical and design approaches.
Online Access
Free
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