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10 records – page 1 of 1.

Characterization and Prediction of Construction Detail Quality and Their Implications for the Customer

https://research.thinkwood.com/en/permalink/catalogue2327
Organization
Université Laval
Country of Publication
Canada
Research Status
In Progress
Notes
Project contact is Pierre Blanchet at Université Laval
Summary
Construction standards are governed by several factors. The National Building Code dictates the minimum to meet occupant safety issues. Energy issues are imposed by the energy efficiency standards of the Novoclimat programs of Transition Energie Québec. However, some developer-builders go further and enforce voluntary environmental standards such as LEED Version 4 or the WELL standard on occupant welfare. Many of these efforts are invisible to the occupier or the buyer because they are hidden in the building assembly, envelope or structure. Over the entire life cycle of buildings, these construction details will be important to the building operator, but their initial costs will also have an impact on the choices made during construction or acquisition. The project proposes to determine the added value of these quality approaches for the consumer. The project will consider key wood building systems by comparing minimum requirements, best practices and consumer perception.
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Air-Coupled Ultrasound Propagation and Novel Non-Destructive Bonding Quality Assessment of Timber Composites

https://research.thinkwood.com/en/permalink/catalogue13
Year of Publication
2012
Topic
Mechanical Properties
Material
Glulam (Glue-Laminated Timber)
Author
Martín, Sergio
Organization
ETH Zurich
Year of Publication
2012
Country of Publication
Switzerland
Format
Thesis
Material
Glulam (Glue-Laminated Timber)
Topic
Mechanical Properties
Keywords
Adhesives
Bonding
Delamination
Failure
Non-Destructive Testing
Air-coupled Ultrasound (ACU)
Finite-Difference Time-Domain (FDTD) model
Language
English
Research Status
Complete
Summary
Glued laminated timber (glulam) is manufactured by gluing and stacking timber lamellas, which are sawn and finger-jointed parallel to the wood grain direction. This results in a sustainable and competitive construction material in terms of dimensional versatility and load-carrying capacity. With the proliferation of glued timber constructions, there is an increasing concern about safety problems related to adhesive bonding. Delaminations are caused by manufacturing errors and in service climate variations simultaneously combined with long-sustained loads (snow, wind and gravel filling on flat roofs). Several recent building collapses were related to bonding failure, which should be prevented in the future with a timely defect detection. As an outlook, the feasibility of air-coupled ultrasound tomography was demonstrated with numerical tests and preliminary experiments on glulam. The FDTD wave propagation model was excited by the difference of the time-reversed sound fields transmitted through a test and a reference (defect-free) glulam cross-section. Both datasets were obtained with the same SLT setup. Wave convergences then provided a map of bonding defects along the height and width of the inspected glulam cross-sections. Further research is envisaged in this direction
Online Access
Free
Resource Link
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Tall Wood Buildings and Indoor Air Quality

https://research.thinkwood.com/en/permalink/catalogue2291
Topic
Environmental Impact
Application
Wood Building Systems
Organization
TallWood Design Institute
Country of Publication
United States
Application
Wood Building Systems
Topic
Environmental Impact
Keywords
Health
Research Status
In Progress
Notes
Project contact is Kevin Van Den Wymelenberg
Summary
New research is showing that wood buildings are more likely to harbor environmental microbes with beneficial health effects. This pilot project will study various surface materials in both the lab setting and occupied mass timber buildings to assess effects on occupants’ health and comfort as well as indoor air quality.
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Monitored Indoor Environmental Quality of a Mass Timber Office Building: A Case Study

https://research.thinkwood.com/en/permalink/catalogue2103
Year of Publication
2019
Topic
Serviceability
Material
CLT (Cross-Laminated Timber)
Glulam (Glue-Laminated Timber)
Application
Wood Building Systems

Evaluation of Brazilian Reforestation Species in Glulam Beams Before and After Preservative Chemical Treatments

https://research.thinkwood.com/en/permalink/catalogue511
Year of Publication
2014
Topic
Mechanical Properties
Material
Glulam (Glue-Laminated Timber)
Application
Beams
Author
de Alcântara Segundinho, Pedro
Calil Neto, Carlito
Dias, Antonio
Calil Junior, Carlito
Year of Publication
2014
Country of Publication
Canada
Format
Conference Paper
Material
Glulam (Glue-Laminated Timber)
Application
Beams
Topic
Mechanical Properties
Keywords
Brazil
Static Bending Test
Chemical Treatment
Copper Chrome Arsenic
Copper Chrome Boron
Language
English
Conference
World Conference on Timber Engineering
Research Status
Complete
Notes
August 10-14, 2014, Quebec City, Canada
Summary
Although the glulam is a product of the nineteenth century, there are few industries in Brazil. The high cost of the structural elements of glulam is committed at the time, its competitiveness with full tropical sawn timber and reforestation. Being a tropical country, we recommend the use of wood treated to prevent termites attack. This study aims to evaluate the resistance of glulam beams before and after being subjected to chemical treatments with pressure using CCA (Copper Chrome Arsenic) and CCB (Copper Chrome Boron). To that end, we tested 54 glulam beams with nominal dimensions of 9 cm x 9 cm x 200 cm, with wood harvested from forest plantations. These beams were subjected to static bending tests, according to Brazilian standard NBR 8458:1984. After analyzing the experimental data it was concluded that the glulam beams produced from wood of Pinus oocarpa had the best results, taking into account the combination wood-adhesive-treatment, because the physical properties remained the same before and after chemical treatment in fullcell method.
Online Access
Free
Resource Link
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Impact of Cracks to the Hygrothermal Properties of CLT Water Vapour Resistance and Air Permeability

https://research.thinkwood.com/en/permalink/catalogue1326
Year of Publication
2017
Topic
Mechanical Properties
Material
CLT (Cross-Laminated Timber)
Author
Kukk, Villu
Horta, R.
Püssa, M.
Luciani, G.
Kallakas, Heikko
Kalamees, Targo
Kers, Jaan
Publisher
ScienceDirect
Year of Publication
2017
Country of Publication
Netherlands
Format
Journal Article
Material
CLT (Cross-Laminated Timber)
Topic
Mechanical Properties
Keywords
Crack Propagation
Crack Formation
Moisture Content
Water Vapour Transmission
Air Permeability
Language
English
Research Status
Complete
Series
Energy Procedia
Summary
Current research is focused on crack formation and propagation in cross laminated timber (CLT) panels and its impacts on the water vapour resistance and air permeability of panels. Crack formation was examined by means of climate tests with five layer CLT-panels with a thickness of 95 mm. Results of climate tests showed that decreasing the moisture content (MC) from 11 % to 7 % caused mean crack widths in panels of 0.27 mm and 0.38 mm, and an MC decreasing from 17 % to 7 % caused mean crack widths of 0.89 mm and 2.0 mm. From these test results it was concluded that in CLT panels which were produced and stored in a humid environment there was an approximate 200% increase in the mean maximum width of cracks compared to panels stored in a dry environment. The water vapour transmission increased by about 9 % with smaller cracks (that were imitated with 2 mm holes) and 30 % with larger cracks (6 mm holes). The air permeability of CLT at a maximum air pressure difference of 550 Pa was 2.25 l/(s*m2) with 2 mm holes and 5.56 l/(s*m2) with 6 mm holes. It can be concluded from the afore mentioned test results that cracks significantly influence the hygrothermal properties of CLT. Deeper investigation as to the reasons, formation and propagation procedures are needed to avoid inadvisable cracks in CLT.
Online Access
Free
Resource Link
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In Plane Shear Strength of Cross Laminated Timber (CLT): Test Configuration, Quantification and influencing Parameters

https://research.thinkwood.com/en/permalink/catalogue2121
Year of Publication
2013
Topic
Mechanical Properties
Material
CLT (Cross-Laminated Timber)
Application
Wood Building Systems

Development of Modular Wooden Buildings with Focus on the Indoor Environmental Quality

https://research.thinkwood.com/en/permalink/catalogue881
Year of Publication
2014
Topic
Environmental Impact
Material
CLT (Cross-Laminated Timber)
Light Frame (Lumber+Panels)
Application
Wood Building Systems
Author
Beikircher, Wilfried
Zingerle, Philipp
Flach, Michael
Year of Publication
2014
Country of Publication
Canada
Format
Conference Paper
Material
CLT (Cross-Laminated Timber)
Light Frame (Lumber+Panels)
Application
Wood Building Systems
Topic
Environmental Impact
Keywords
Indoor Air Quality
Indoor Climate
Modular Construction
Language
English
Conference
World Conference on Timber Engineering
Research Status
Complete
Notes
August 10-14, 2014, Quebec City, Canada
Summary
During the last three decades there has been increasing concern within the scientific community about the effects of indoor air quality on health. Changes in building design devised to improve energy efficiency and has induced that modern homes and offices are frequently more airtight than older structures. Furthermore advances in construction technology have caused an extensive use of synthetic building materials. The construction process and the production of building materials not only consume the most energy they also have a big impact on the Global Warming Potential. While these improvements have led to more comfortable buildings with lower running costs, they also provide indoor environments in which contaminants are readily produced and may build up to much higher concentrations than outside. Because about 80-90% of our time is spent indoors, where we are exposed to chemical and biological contaminants and possibly carcinogens, the Indoor Environmental Quality plays an increasing role. The aim of this study was to develop building components out of sustainable natural materials for modular building concepts with regard to the Indoor Environmental Quality such as the air quality and the indoor climate, the temperature and humidity. To guarantee high Indoor Air Quality a mechanical ventilation system is part of the construction. It has to ensure a controlled air change with a minimum of dissipation of energy. Building parts were assembled to meet high energy efficiency Standards. For the construction parts wood, hemp, sheep wool and clay were used to meet the settled requirements. As a first result of this study two modular buildings were erected, in which the indoor air quality and the construction physics will be monitored in the next few years for generating valuable data.
Online Access
Free
Resource Link
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Structural Health Monitoring and Post-Occupancy Performance of Mass Timber Buildings

https://research.thinkwood.com/en/permalink/catalogue2290
Topic
Serviceability
Environmental Impact
Material
CLT (Cross-Laminated Timber)
Application
Wood Building Systems
Organization
TallWood Design Institute
Country of Publication
United States
Material
CLT (Cross-Laminated Timber)
Application
Wood Building Systems
Topic
Serviceability
Environmental Impact
Keywords
Durability
Monitoring
Livability
Research Status
In Progress
Notes
Project contact is Mariapaola Riggio.
Summary
A key question about new generation taller wood buildings is how they will perform over time in terms of durability and livability. This project will determine how best to measure these qualities by selecting sensors, determining testing and measurement protocols, and implementing testing assemblies in selected CLT buildings in Oregon. Future research will use the knowledge developed through this project to carry out post-occupancy monitoring, generating valuable new insights into building performance.
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Experimental Campaign for the Mechanical Characterization of Connection Systems in the Seismic Design of Timber Buildings

https://research.thinkwood.com/en/permalink/catalogue1511
Year of Publication
2016
Topic
Connections
Mechanical Properties
Seismic
Material
CLT (Cross-Laminated Timber)
Light Frame (Lumber+Panels)
Application
Wood Building Systems
Author
Casagrande, Daniele
Polastri, Andrea
Sartori, Tiziano
Loss, Cristiano
Chiodega, Manuela
Year of Publication
2016
Country of Publication
Austria
Format
Conference Paper
Material
CLT (Cross-Laminated Timber)
Light Frame (Lumber+Panels)
Application
Wood Building Systems
Topic
Connections
Mechanical Properties
Seismic
Keywords
Capacity
Stiffness
Ductility
Cyclic Loads
Monotonic Loads
Language
English
Conference
World Conference on Timber Engineering
Research Status
Complete
Notes
August 22-25, 2016, Vienna, Austria p. 353-361
Summary
The seismic behaviour of timber buildings is strongly related to the energy dissipation capacity of connections. According to Standard, since timber is characterized by a brittle failure when subjected to tensile or bending actions, the dissipative zones shall be located in joints and connections, whereas timber members themselves shall be regarded as behaving elastically. In order to ensure the global structural ductility, connections and joints shall be able to deform plastically at the associated ductility level without a significant reduction of their resistance under cyclic loads. The paper deals with an experimental campaign for the mechanical characterization of timber connection systems, commonly adopted in Europe, in the seismic design of timber buildings. The main objective was to find out the capacity, the stiffness and the ductility of the tested connections and to investigate their loss of capacity under cyclic loads. The obtained results were analysed in order to understand if the current provisions, reported in Standard for the different typology of traditional connectors, can be adopted in case of connection systems used for seismic purposes, such as hold-down or angle brackets. Their interaction with other structural parts was then investigated testing six fullscale timber walls, subjected to monotonic and cyclic loads. The tests were carried out at the Laboratory of Materials and Structural Testing of the Trento University (Italy).
Online Access
Free
Resource Link
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10 records – page 1 of 1.