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CLT
Oregon State University
College of Forestry
CROSS LAMINATED TIMBER Department of Wood Science and Engineering
Evaluating Effects of Non-Uniform Scaling On Structural Properties
Using Digital-Image Correlation Deflection Mapping
Introduction Benjamin Sundberg - Undergraduate Research Fellow OSU COF:WSE COE:CCE
Cross Laminated Timber (CLT) is a Lech Muszynski - Associate Professor OSU COF WSE
relatively new timber product which consists Melanie Noyel - International Graduate Intern Digital Image Correlation
of orthogonally oriented dimensioned lumber Thomas Pisaneschi - International Graduate Intern The deformation of panels during
glued together similar to laminated veneer Vaclav Sebera - Mendel Uni. Brno mechanical testing were recorded using
plywood. CLT is cur r ently being used in full field optical measurements based on
Europe but has not yet emerged into the North American Market. the digital image correlation (DIC) principle.
One of the reasons for this is the lack of standards and testing Research in Progress at OSU Stereographic images of the deflected
procedures for the material. surface are captured by a pair of digital
Objectives:
camer as and ar e then pr ocessed by
The pr imar y goals of the r esear ch at Or egon State
advanced computer software.This system
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University are to:
History of CLT - Develop testing protocols for panel specimens utilizing
returns full field deflection maps across the
surface of the panel. This is a great advantage to the traditional topical
CLT was developed in Sweden in the 1970's. However, it wasn't non-contact full field optical measurement based on
measurement of limited discrete points using LVDT's. Full f ield
marketed or produced until the early 1990's. In 1996, Austria Digital Image Correlation (DIC).
deflection measurements enable more accurate comparisons of the
undertook a joint industry-academic research venture that - Derive correction factors which will allow predicting
outcomes with analytical models and FEM simulations. The anisotropic
standardized the production process and testing procedures the mechanical performance of full sized structural
nature of the panels may be reflected and characterized in a single test.
ultimately creating modern CLT. panels f rom tests perf ormed on smaller panels
This new and exciting technique has been integral in developing the
specimens. Smaller panels are easier and less
scaling factors for approximating full size panel performance from tests
2007 - the Japanese erected a full scale seven story CLT structure expensive to manuf acture f or entrepreneurs
on smaller specimens.
on the world's largest seismic shake considering entering the market.
table "E-Defense" and subjected the -
building to 10 earthquakes in a row. Materials:
Fr om this test, the r esear cher s Oregon Hybrid Poplar harvested from Collins/Greenwood Conclusions and Future Work
concluded that CLT is very good at plantation near Boarman, OR. PRF resin formulated for Conclusions: The analysis of the full field deflection data acquired from
resisting seismic forces. glulam beams from Hexiom Specialty Chemicals. optical measurements is pending. The precision and accuracy of the
optical measurement is specific to the experimental setup. In our tests
2010 - The Bridgeport House, The study included: the pr ecision of the out of plane def lection was within 0.001"
constructed almost entirely out of Determination of optimal bonding conditions conducted on
cross laminated panels, was finished small billets. Future work includes the
in London. At 9 storey, the Bridgeport House is the tallest timber construction of full size structural
structure in the world . Construction of 3-Layer CLT Panel specimens for panel specimens, and the
mechanical testing (2'x2', 4'x4', 4'x8') bending and torsion tests on
2010 - Researchers at OSU began pilot tests on hybrid poplar CLT. those panels. The data generated
Mechanical testing of small and medium sized panels in from these tests will allow us to
2011 - FP Innovations Canada releases CLT Handbook - First step torsion and center point bending. Including FEM simulation develop the correction factors for
towards North American market emergence. of these mechanical tests. This portion of the study is in tests done on small scale
progress. specimens.
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