Failure tests on full scale models of grout laminated wood decks

A grout laminated wood deck (GLWD) comprises wood
laminates, or logs trimmed to obtain two vertical faces, held
together by internal grout cylinders, also referred to as shear
keys, which are prestressed with rods of steel or glass fibre
reinforced polymers (GFRP). There are two methods of constructing
GLWD. In one scheme of construction, the deck is
compressed laterally by tendons in regularly spaced transverse
holes within the deck. After stressing the deck, the
holes are filled with a grout. The prestressing force is removed
from the rods after the grout has set, thus putting the
grout cylinders in compression. For ease of reference, the
deck resulting from this method of construction is referred
to as the GLWD with grout cylinders in compression or
GLWD-C.
In the other method of construction, the deck is compressed
by an external prestressing system and the transverse
holes in the deck, containing the rods, are filled with a grout.
After the grout has set, the external prestressing system is
removed, inducing a tensile force in the grout cylinders,
most of which develop small transverse cracks along their
length. The deck obtained by this form of construction is referred
to as the GLWD with grout cylinders in tension or
GLWD-T.
Full-scale models of both forms of construction of GLWD
were constructed at Dalhousie University. The GLWD-C
employing steel rods was built about 3 years ago, and the
GLWD-T with GFRP rods about 2 years ago. A set of initial
tests conducted on the two models have confirmed that the
grout cylinders, whether cracked or not, are effective in the
lateral transfer of concentrated loads. Unlike stress laminated
wood decks, GLWDs are not affected by prestress
losses.
The two models of GLWDs were recently moved to The
University of Manitoba in Winnipeg, where each was tested
to failure under a central patch load. It was confirmed that
the decks can be assembled and stored for prolonged periods
of time without adversely affecting their performance, thus
making them an excellent choice for emergency use. The ultimate
load tests are described herein and the pre-failure test
results compared with those from the earlier tests.
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