Comparison of mechanical properties of solid wood and laminated veneer lumber fabricated from Turkish beech, Scotch pine, and Lombardy poplar by ProQuest


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									                 Comparison of
            mechanical properties
         of solid wood and laminated
    veneer lumber fabricated from Turkish
   beech, Scotch pine, and Lombardy poplar

                       Yusuf Ziya ErdilS    Ali KasalS     Jilei ZhangS
                                  Hasan Efe      Taner Dizel

    Selected mechanical properties of laminated veneer lumber (LVL) prepared from Turkish beech (Fagus orientalis L.),
Scotch pine (Pinus sylvestris L.), and Lombardy poplar (Populus nigra) veneers bonded with polyvinyl acetate and urea-
formaldehyde adhesives and solid wood specimens of the same species were tested to evaluate the effects of species, adhesive
type, and veneer grain orientation. The mechanical tests evaluated were compression and tensile strengths parallel to the
grain, bending strength, modulus of elasticity, cleavage strength perpendicular to the grain, and block shear. Test results
showed that the effects of wood species on all of the mechanical properties were statistically significant. Also, adhesive type
was found to have a significant effect on the strength properties of the LVL specimens. But, considering the design flexibility
with different forms and sizes and the opportunity to better utilize low-quality wood, LVL can be recommended as an
alternative to solid wood. Results also showed that LVL could be utilized instead of solid wood material in different areas
such as building and furniture constructions because most strength properties of LVL were at least as good as solid wood of
the same species.

   W      ith an increased demand for lumber worldwide, the
amount of solid timber available has steadily declined. To
                                                                    (apitong) on wearing surfaces such as truck decking, box
                                                                    beams, kiln stickers, and door rails capitalize on the versatility
meet the ever-rising demand, it is crucial to use proper pro-       and consistency of properties exhibited by LVL (USDA
duction techniques for the best yield. Increasingly, composite      1987).
materials are being used in the construction of furniture
                                                                      Eckelman (1993) identified applications and constructions
frames and buildings.
                                                                    in which LVL could be used to best advantage, from both
   Laminated veneer lumber (LVL), which is made from                a structural and an economical point of view. Some detailed
veneers (Aydin et al. 2004), has been developed as an alterna-
tive material to solid wood. LVL is an engineered wood prod-
uct and represents an efficient use of available timber. It offers      The authors are, respectively, Professor and Associate Professor,
several advantages over typical milled lumber: it is stronger,      Dept. of Wood Sci. and Furniture Design, Mugla Univ., Mugla,
straighter, and more uniform. It is much less likely to warp,       Turkey (,; Professor, Forest
twist, bow, or shrink than conventional lumber. Furthermore,        Products Lab., Mississippi State Univ., Mississippi State, Missis-
LVL makes use of timber of smaller dimensions, yet is engi-         sippi (; Professor, Dept. of Wood Sci. and
                                                                    Furniture Design, Gazi Univ., Ankara, Turkey (hasanefe@gazi.
neered to be stronger than similarly sized members comprised; and Lecturer, Dept. of Wood Sci. and Furniture Design,
of solid wood. It is typically used for headers, beams, rimboard,   Kırıkkale Univ., Kırıkkale, Turkey (taner_dizel_kku@hotmail.
and edge-forming material. It is similar in appearance to ply-      com). This paper was received for publication in August 2008.
wood and is stress rated for structural applications.               Article No. 10519.
                                                                    S Forest Products Society Member.
   As a recent technology, the processes and uses for LVL are       ÓForest Products Society 2009.
evolving. Using abrasion-resistant species such as keruing            Forest Prod. J. 59(6):55–60.

FOREST PRODUCTS JOURNAL                  VOL. 59, NO. 6                                                                             55
information on the production techniques, technological prop-     and Lombardy poplar (Populus nigra L.). The plys were
erties, advantages, and disadvantages of LVL products can be      placed on top of each other in various arrangements and
found in the literature (Baldwin 1995, Kamala et al. 1999).       bonded with a vinyl-based adhesive. Results of the study
Fonselius (1997) investigated the effect of size on bending       showed that bending strength and stiffness of the solid wood
strength of LVL produced from spruce (Picea abies) and pine       both perpendicular and parallel to the glueline were smaller
(Pinus sylvestris). Results indicated that width was found to     than those of LVL made of the same species.
have no effect on bending strength while length and depth
                                                                    This study was conducted to:
affected bending strength. Results also showed that size had
no effect on modulus of elasticity (MOE) and modulus of              1. obtain background information concerning the physi-
rigidity (MOR) (Fonselius 1997). Strength properties of par-            cal and mechanical strength properties of 11-layer
allel strand lumber (PSL) made of rubber wood (Heavea bra-              LVL specimens fabricated from Turkish beech (Fa-
siliensis) and an exterior type adhesive were evaluated in air-         gus orientalis L.), Scotch pine (Pinus sylvestris L.),
dry conditions. Comparisons of these strength values were               and Lombardy poplar (Populus nigra) veneers bonded
made with those of LVL, solid rubber wood, and standard                 with two different types of adhesives: polyvinyl ace-
teak. Results showed that the PSL had slightly lower strength           tate (PVAc) and urea-formaldehyde (UF);
properties compared to teak and solid rubber wood. The               2. evaluate the effects of wood species, adhesive type,
strength properties were quite inferior to those of LVL (Shu-           and veneer grain orientation on LVL mechanical
kla et al. 1999). Aydin et al. (2004) determined and compared           properties; and
physical and mechanical properties of LVL produced from
beech (Fagus orientalis Lipsky) and eucalyptus (Eucalyptus           3. evaluate the strength and stiffness properties of LVL
camaldulensis Dehn.). They found that the effects of wood               compared to the control sol
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