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8 records – page 1 of 1.

Quantifying the Impacts of Moisture and Load on Vertical Movement in a Simulated Bottom Floor of a 6-Storey Platform Frame Building

https://research.thinkwood.com/en/permalink/catalogue2619
Year of Publication
2013
Topic
Moisture
Design and Systems
Material
Light Frame (Lumber+Panels)
Application
Wood Building Systems
Author
Wang, J.
King, L.
Organization
FPInnovations
Year of Publication
2013
Country of Publication
Canada
Format
Report
Material
Light Frame (Lumber+Panels)
Application
Wood Building Systems
Topic
Moisture
Design and Systems
Keywords
Mid-Rise
Vertical Movement
Moisture Content
Shrinkage
Load-Induced Movement
Language
English
Research Status
Complete
Summary
Vertical movement of wood frame buildings has become an important consideration in recent years with the increase of building height in Europe, North America, and Asia up to 6-storeys. This movement is composed of wood shrinkage and load-induced movement including initial settlement and creep. It is extremely difficult to identify the relative contributions of these components while monitoring full size buildings. A laboratory test was therefore designed to do this under controlled environmental and loading conditions. Two identical small-scale platform frame structures with dimensional lumber floor joists were designed and constructed, with built-in vertical movement and moisture content monitoring systems. The two structures were first conditioned in a chamber to achieve an initial moisture content (MC) about 20% to simulate typical MC on exposed construction sites in wintertime in Coastal BC. After the two structures were moved from the conditioning chamber into the laboratory environment, using a unique cantilever system, Structure No. 1 was immediately loaded to measure the combined shrinkage and deformation in the process of drying. Structure No. 2 was not loaded until after the wood had dried to interior equilibrium moisture content to observe the shrinkage and load-induced movement separately. The load applied on the two structures simulated a dead load experienced by the bottom floor of a six-storey wood frame building. The vertical movement and MC changes were monitored over a total period of six months. Meanwhile, shrinkage coefficients were measured by using end-matched lumber samples cut from the plate members of the two structures to predict the shrinkage amounts of the horizontal members of the two structures. The results suggested that a load must be applied for movement to “show up” and occur in a downward direction. Without loads other than the wood weight, even shrinkage could show as upward movement. Monitoring of Structure No. 1 appeared to separate the contributions of wood shrinkage, initial settlement (bedding-in movement), and creep reasonably well. The entire movement amount reached about 19 mm after six months, which was comparable to the vertical movement measured from the bottom floor of a 4-storey wood-frame building in BC. Shrinkage accounted for over 60% of the vertical movement, with the other 40% contributed by load-induced movement including initial settlement and creep (when elastic compression was neglected); the magnitude of creep was similar to the initial settlement amount. Structure No. 2 showed less vertical movement but an increased settlement amount at the time of loading, indicating the presence of larger gaps between members when the wood was dry (with an estimated MC of 11%) before loading. Depending on construction sequencing, such settlement should occur with increase in loads during construction and can therefore be ignored in design. However, this test suggested that there may be a need to consider the impact of creep, in wet climates in particular, in addition to wood shrinkage. This laboratory test will be maintained for a longer period to observe any further vertical movement and the relative contributions of shrinkage and creep. Similar tests should be conducted for structures built with engineered wood floor joists, given the fact that most mid-rise platform buildings use engineered wood floor joists instead of lumber joists.
Online Access
Free
Resource Link
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Review and Survey on Differential Movement in Wood Frame Construction

https://research.thinkwood.com/en/permalink/catalogue2627
Year of Publication
2010
Topic
Design and Systems
Material
Light Frame (Lumber+Panels)
Application
Wood Building Systems
Author
Wang, J.
Ni, Chun
Organization
FPInnovations
Year of Publication
2010
Country of Publication
Canada
Format
Report
Material
Light Frame (Lumber+Panels)
Application
Wood Building Systems
Topic
Design and Systems
Keywords
Deformation
Mid-Rise
Shrinkage
Movement
Language
English
Research Status
Complete
Summary
This report summarizes the existing knowledge on building movement related to wood-frame construction. This knowledge includes fundamental causes and characteristics of wood shrinkage, instantaneous and time-dependent deformations under load, major wood-based materials used for construction and their shrinkage characteristics, movement amounts in publications based on limited field measurement, and movement estimations by construction practitioners based on their experience with wood-frame construction. Movement analysis and calculations were also demonstrated by focusing on wood shrinkage based on common engineering design assumptions, using six-storey platform buildings as examples. The report then provides engineering solutions for key building locations where differential movement could occur, based on the literature review as well as a small-scale survey of the construction industry. The report emphasizes the importance of comprehensive analysis during design and construction to accommodate differential movement. Most building materials move when subjected to loading or when environmental conditions change. It is always good practice to detail buildings so that they can accommodate a certain range of movement, whether due to structural loading, moisture or temperature changes. For wood-frame buildings, movement can be reduced by specifying materials with lower shrinkage rates, such as engineered wood products and drier lumber. However, this may add considerable costs to building projects, especially when specifications have to be met through customized orders. Producing lumber with a lower moisture content adds significant costs, given the additional energy consumption, lumber degrade and sorting requirements during kiln drying. Specifying materials with lower moisture content at time of delivery to job site does not guarantee that wood will not get wet during construction, and excessive shrinkage could still be caused by excessively long time of exposure to rain during construction. On the other hand, effective drying can occur during the period between lumber delivery and lumber closed into building assemblies. Appropriate measures should be taken to ensure lumber protection against wetting, protected panel fabrication on site, good construction sequence to facilitate air drying, and supplementary heating before closing in to improve wood drying. This report also provides recommendations for future work, including field measurement of movement and construction sequencing optimization, in order to provide better information for the design and construction of wood buildings, five- and six-storey platform frame buildings in particular.
Online Access
Free
Resource Link
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Seismic Design of Timber Buildings with a Direct Displacement-Based Design Method

https://research.thinkwood.com/en/permalink/catalogue1904
Year of Publication
2013
Topic
Seismic
Design and Systems
Material
Light Frame (Lumber+Panels)
Timber (unspecified)
Application
Frames
Wood Building Systems

Seismic Performance of Multi-Storey Timber Buildings Legnocase Building

https://research.thinkwood.com/en/permalink/catalogue375
Year of Publication
2013
Topic
Seismic
Material
Light Frame (Lumber+Panels)
Application
Wood Building Systems

Seismic Performance of Wood Mid-Rise Structures

https://research.thinkwood.com/en/permalink/catalogue343
Year of Publication
2013
Topic
Seismic
Material
Light Frame (Lumber+Panels)
Application
Wood Building Systems

Seismic Retrofit of Soft-Story Woodframe Buildings using Cross Laminated Timbers

https://research.thinkwood.com/en/permalink/catalogue215
Year of Publication
2013
Topic
Seismic
Material
CLT (Cross-Laminated Timber)
Light Frame (Lumber+Panels)
Application
Wood Building Systems
Author
van de Lindt, John
Bahmani, Pouria
Gershfeld, Mikhail
Kandukuri, Giraj
Rammer, Douglas
Pei, Shiling
Year of Publication
2013
Country of Publication
United States
Format
Journal Article
Material
CLT (Cross-Laminated Timber)
Light Frame (Lumber+Panels)
Application
Wood Building Systems
Topic
Seismic
Keywords
Retrofit
Soft-Story
Numerical model
US
Full Scale
Language
English
Conference
International Structural Engineering and Construction Conference
Research Status
Complete
Notes
June 18-23 2013, Hononlulu, Hawaii, USA
Online Access
Free
Resource Link
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Surface Burning Characteristics of Massive Timber Assemblies

https://research.thinkwood.com/en/permalink/catalogue397
Year of Publication
2013
Topic
Fire
Material
CLT (Cross-Laminated Timber)
LSL (Laminated Strand Lumber)
PSL (Parallel Strand Lumber)
Application
Wood Building Systems
Author
Dagenais, Christian
Organization
FPInnovations
Year of Publication
2013
Country of Publication
Canada
Format
Report
Material
CLT (Cross-Laminated Timber)
LSL (Laminated Strand Lumber)
PSL (Parallel Strand Lumber)
Application
Wood Building Systems
Topic
Fire
Keywords
Flame Spread
National Building Code of Canada
Language
English
Research Status
Complete
Summary
Advanced wood building systems form a significant market opportunity for use of wood in taller and larger buildings, which are currently required to be of non-combustible construction in accordance with the provisions set forth in Part 3 of Division B of the...
Online Access
Free
Resource Link
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Vertical Movement in Wood Platform Frame Structures: Design and Detailing Solutions

https://research.thinkwood.com/en/permalink/catalogue736
Year of Publication
2013
Topic
Serviceability
Material
Light Frame (Lumber+Panels)
Application
Wood Building Systems
Author
Doudak, Ghasan
Lepper, Peggy
Ni, Chun
Wang, Jasmine
Organization
Canadian Wood Council
FPInnovations
Year of Publication
2013
Country of Publication
Canada
Format
Report
Material
Light Frame (Lumber+Panels)
Application
Wood Building Systems
Topic
Serviceability
Keywords
Differential Movement
Language
English
Research Status
Complete
Summary
Most buildings are designed to accommodate a certain range of movement. In design, it is important for designers to identify locations where potential differential movement could affect structural integrity and serviceability, predict the amount of diffe...
Online Access
Free
Resource Link
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8 records – page 1 of 1.