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Engineered Lumber
Wood that is manufactured by bonding together wood strands, veneers, lumber or fiber to produce a stronger and more uniform composite. Engineered lumber does not require the use of mature growth trees and typically results in less production and job-site waste.
Characteristics
Engineered wood products are used in a variety of ways, often in applications similar to solid wood products. Engineered wood products may be preferred over solid wood in some applications due to certain comparative advantages:
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Because engineered wood is man-made, it can be designed to meet application-specific performance requirements.
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Large panels of engineered wood may be manufactured from fibres from small diameter trees.
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Small pieces of wood, and wood that has defects, can be used in many engineered wood products, especially particle and fiber-based boards.
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Engineered wood products are often stronger and less prone to humidity-induced warping than equivalent solid woods.
Hardwood Facts
Until a few decades ago, Bolivian wood was studied very little
in the country, because of the lack of specialized technical people
and of the adequate equipment to perform test and corresponding
exercises.
Fragmented information exists about some various native wood
species tested in foreign laboratories. Sometimes, the studies
were conducted through restlessness of institutions to governmental
standards like " the Bolivian - Argentina Mixed Commission
or representatives of all private activity, interested in knowing
the property of our wood and to promote a better use of them.
Toward the mid-70's, the countries of the The Andes Pact (Bolivia,
Colombia, Ecuador, Peru and Venezuela) introduced in the sub regions
a integral study of the wood that was know little in each country.
In this time, they realized that an agreement and installation
of two technological wood laboratories, in the cities of Tarija
(equipment brought by the university) and Santa Cruz (equipment
donated by IDRC of Canada) with the promotion of a national wood
investigation began.
They have enough various information of the performed studies
or the process of execution about the physics , mechanics societal
and anatomical structure characteristics of the Bolivian wood.
Lamentably, all this technical information is scattered in different
investigation, production, commercialization, and use of the wood,
a situation that sometimes gives many places duplicated information.
For example, "el jichiturique" is a wood that was studied
for its physical properties and initial mechanics through the
CDF (Center of Forrest Development ) between 1979 and 1980; but
during this time the "Camara" National Forest studied
the same wood and found similar information.
Actually, there is a market interest in the country and an international
standard through promotion of the use of the tropical wood.
The exertion of the technological investigation in the wood circulation
of the results are technical and economically felt by some worlds
like Japan, Spain, Switzerland, Germany, the United States, and
the European Economic community, and others.
It is hoped that future national and Latin-American standards
will keep better dates and technical publications about our wood.
The objective of this present work is bring together the best
technical information about our wood, that has been studied in
the country and aboard and condensed into documents and distributed.
The information refers to the identification of botany, commercial
names, physical properties, mechanical properties, workability,
preservation, natural durability, and finally the possible uses
and applications. In some cases, we were not able to get all of
the information. All the information we found is listed in order
and has been distributed to the specific countries.
For information to be effective we have consulted various information,
personal records,m institutional archives from the world, from
the industrial wood companies, Universities, libraries in Santa
Cruz, La Paz, Tarija and Yacuiba, and places where material has
been relocated.
The information was completed with observation from the authors
and accumulated through many long years of work in state and private
institutions.
COMMON NAME: Ochoo, Soliman
COMMERCIAL NAME: Possumwood, Assacu (22) (54)
SCIENTIFIC NAME: Hura crepitans L.
FAMILY: Euphorbiaccae
DISTRIBUTION AREA: In transition, seeks tropical humidity to subtropical
humidity, sections of Santa Cruz, Beni, Cochabamba, La Paz, Pando (13)
GENERAL CHARACTERISTICS OF THE TREE: The total height approximately
is 40 meters, treetop large, intensely green foliage color, alternate
leaves, simple; color of bark clear brown to grayish color, from appearance
it looks smooth, but it has pricklers approximately 6mm., after it diminishes,
it exudes a yellowish caustic latex color, dangerous to the view, diluted
in water is toxic and venomous; thickness of the bark is 2 to 5cm., conical
shaft.
GENERAL CHARACTERISTICS OF THE WOOD: Sapwood color is white, gradual
final change to a yellow color; without odor characteristics, some caustic
flavor, straight grain; smooth grain; differentiated growth rings; porosity
diffusion, large pores visible through simple view, limited (less than
3mm squared) solitary and in radial multiples of four, large and very
large (o.20-0.40mm); slender radius (less than 0.05 mm) not straight,
visible with a magnifying glass, numerous (45 to 60 by 5mm),; absent stratification.
PHYSICAL PROPERTIES:
Density at 12 % controlled humidity = 0.52 gr/m3
Total radial contraction = 3.9%
Total tangential contraction = 5.7%
Appraisal (T/R) = 1.5 stable wood
Total volumetric contraction = 9.7%
Basic weight = 0.44 average
Total porosity = 6.8%
Saturation point of fibers = 25%
MECHANICAL PROPERTIES:
| Flexion |
Parallel Compression |
Lateral |
| Break Exertion |
Break Exertion, |
Strength |
Wood humidity
(Concentration less than 30%) = |
|
| 489 kg/cm2 |
259 kg/cm2 |
241 kg |
| At 12% of concentration |
|
=475 kg/cm2 |
| 685 kg/cm2 |
445 kg/cm2 |
364 kg |
EXERTION OF STRUCTURAL DESIGN, ACCORDING TO THE ANDES PACT
Flexion = 100 kg/cm2
Parallel Compression = 80 kg/cm2
Perpendicular Compression =15 kg/cm2
Parallel shears =8 kg/cm2
Modulation of average elasticity =90,000kg/cm2
Work corresponds to structural group C.
EXERTION OF DESIGN KGR/NAIL
|
2 1/2" Nails |
4" Nails |
| Double
shears |
26 |
52 |
|
Simple shears |
20 |
37 |
WORKABILITY:
Wood is easy to work with, a successful finish can be
obtained. In dry air, the board have bends and curves.
PRESERVATION & DURABILITY: Wood is moderately permeable
absorption good in a hot-cold bath of pentachlorophenol at 5 % concentration,
results between 132 and 194 kg/m3. It has an elevated absorption in treatment
at pressure, results between 327 and 788 kg/m3. Green lumber from the
saw is not durable, but proper treatment including chemical baths, air
and kiln drying makes it suitable for high quality millwork.
USES & APPLICATION:
Carpentry, cabinetmaking, paneling, (short rotary and together), plywood,
sets of drawers, interior work, molding, plywood, toys, chest of drawers
in a vestry. In the 70s, wood was exported to Argentina, Brazil, the US,
and Italy.
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