Skip to main content

Physical and mechanical properties of densified veneer wood (DVW) forstructural applications

Objective

The project has the following goals:

The mechanical and physical properties of densified veneer wood (dvw) made of poplar and maritime pine will be investigated and compared with softwood. The ability of the dvw to withstand concentrated loads will be investigated as to satisfy the demands for structural applications.

Densified veneer wood (dvw) has the po
tential ability of being a realistic a
lternative for tropical wood and with
preservative treated wood. Improvement
of the mechanical and physical proper
ties of dvw can be achieved by better
grading which is necessary for various
structural and non-structural applica
tions. The introduction in the EC of a
reliable NDT machine grading method r
esult in a better grading of veneer, t
he raw material of the densified venee
r wood. This grading method could well
become a standard grading method in t
he EC as in the USA, although the EC w
ood species are different. The market
replacement ability of the dvw for tro
pical and with preservative treated wo
od is in agreement with EC-policies. B
y gluing dvw to timber a composite is
created which can have many advantages
and therefore can improve market pros
pects and stimulate the competitivenes
s of timber. In short the next subject
s will be covered: a) - As main item:
Introduction of a reliable NDT-machine
grade method for veneer,as in the EC
only visual methods are being used. Th
e machine grade settings are related t
o a strength class segregation of the
dvw which will be verified by mechanic
al and physical tests. Dvw is obtained
by lamination and compression of cros
swise layered graded veneer sheets.
b) - Veneer of low quality, beech, pop
lar and maritiem pine will be utilised
for the production of dvw. Resistance
against moisture, fungal and beetles
is part of the program.
c) - The dvw will be glued to timber i
n order to reinforce or to protect the
wood against mechanical and/or biolog
ical attack.
The dimensional stability of this comp
osite will improve.
d) - Reinforcement by dvw of the timbe
r of joints open new possibilities for
structural application. Combined with
a tube fastener the strength stiffnes
s and ductility properties will increa
se considerable. This will result in e
conomic more competitive timber struct
ures with improved market penetration
capabilities. In the near future Euroc
ode 8 regulations will discourage the
use of wood in seismic zones because o
f the lack of ductility of present tim
ber joints. As tentative results show
this dvw reinforced joint is very prom
issing in satisfying Eurocode 8 requir
ements.
The production proces of densified ven
eer wood is known for more than 100 ye
ars and consists of compression of pil
es of veneer sheets at a temperature o
f about 120C. This pressure closes the
hollow space of the wood fibre. When
the wood fibre is closed the temperatu
re is decreased rapidly leading to pet
rification of the cell walls which lea
d to the dimensional stabilisation of
the compressed wood.

Coordinator

Technische Universiteit Delft
Address
1,Stevinweg 1
2628 BL Delft
Netherlands

Participants (7)

De Groots Gelijmde Houtconstructies BV
Netherlands
Address
77,Chrchillstraat
7680 AA Vroomshoop
Holzbau SpA
Italy
Address
Via Ammon 12
39042 Bolzano - Brixen
LABORATORIO NACIONAL DE ENGENHARIA CIVIL
Portugal
Address
101,Avenida Do Brasil 101
1700-066 Lisboa
Lignostone Ter Apel BV
Netherlands
Address
3,Mercuriusweg
9561 AL Ter Apel
UNIVERSITY OF FLORENCE
Italy
Address
Via Santa Marta 3
50139 Firenze
University of Brighton
United Kingdom
Address
Lewes Road
BN2 4GJ Brighton
Universität Karlsruhe (Technische Hochschule)
Germany
Address
Kaiserstraße 12
76131 Karlsruhe