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MATERIALS 57
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displacement that was 7 percent more than the actual Das et al. showed superior bonding performance of both
values. Furthermore, FEM was shown to underestimate the poplar and hybrid maple–poplar CLT, compared to spruce
maximum load capacity of thinner panels by 4 percent, while (Picea abies (L.) H. Karst.) CLT.
overestimating it by 20 percent for thicker panels. This study was carried out with the that CLT from poplar,

In contrast, Navaratnam et al. observed that the FEM which has a density almost comparable to that of spruce,
underestimated the bending stiffness of three-layered radiata may match or surpass the conventional spruce CLT in terms
pine CLT by five percent while overestimating it by 13 percent of both bending and rolling shear performance.
for five-layered CLT. Additionally, the study also explores the potential benefits of
As CLT is a structural component, its mechanical properties hybrid CLT panels prepared by combining low-density poplar
like Emg, fm, and fr must be considered during structural design. in the core and high-density maple in the outer layer with an
Furthermore, designing wall, floor or roof assemblies expectation to achieve enhanced load-bearing capabilities,
composed of CLT panels needs consideration for the maximum material efficiency, and reduced risk of rolling shear failure.
compressive stress both parallel and perpendicular to the Utilisation of low-density and underutilised hardwoods

grain directions. in CLT production aligns with sustainability objectives by
Several studies indicated that hardwood CLTs outperformed enhancing the resource base.
the typical softwood CLTs in terms of mechanical properties, The experimental results were compared with theoretically
like load-bearing capabilities, material consumption, and the predicted values from three different methodologies: Timoshenko
risk of rolling shear failure. beam theory, shear analogies, and modified gamma. Additionally,
Still, the bond line delamination in hardwood CLTs is a finite element models (FEMs) were utilised to evaluate the
major drawback. Moreover, increasing demand for CLT and bending stiffness.

expansion of plantation-grown hardwood forests, like poplar
and other cultivated species necessitates the researchers Materials For The Experiment
to explore the feasibility of utilising these materials in CLT The study included two hardwood species, poplar (Populus
manufacturing. nigra L.) and maple (Acer platanoides L.), as well as a softwood,
This exploration involves analysing their properties in Norway spruce (Picea abies (L.) H. Karst.), which were obtained
homogeneous CLT panels made entirely from single species from a commercial provider (woodstore) in the Czech Republic,
and hybrid CLT panels that combine different wood species. and possessed the nominal dimensions of a 150 mm width,
Selecting suitable species depends on factors such as a three metre length, and a thickness of 30 mm.
resource availability, economic viability and compliance with

established minimum performance criteria to ensure that the
chosen species or combination of species meets the required Auburn University
structural and environmental standards.
In the Czech Republic, poplar (Populus spp.) and maple
(Acer spp.), two common fast-growing species, make up
around 24 percent of the avenue plantations.
\Moreover, the latest iteration of EN 16351 identifies poplar

as the sole hardwood species for the production of CLT
panels, with minimal study concerning maple.