Upload
pametnica21
View
34
Download
2
Tags:
Embed Size (px)
DESCRIPTION
drvo
Citation preview
Glued laminated timber, also
called glulam, is a type of
structural timber product comprising a
number of layers ofdimensioned
timber bonded together with durable,
moisture-resistant structural adhesives. In
North America the material providing the
laminations is termed laminating
stock or lamstock.
By laminating a number of smaller pieces
of timber, a single large, strong, structural
member is manufactured from smaller
pieces. These structural members are
used as vertical columns or
horizontal beams, as well as curved,
arched shapes. Glulam is readily
produced in curved shapes and it is
available in a range of species and
appearance characteristics to meet varied
end-use requirements.[1] Connections are
usually made with bolts or plain steel
dowels and steel plates.
Glulam optimizes the structural values of a
renewable resource – wood. Because of
their composition, large glulam members
can be manufactured from a variety of
smaller trees harvested from second- and
third-growth forests and plantations.
Glulam provides the strength and
versatility of large wood members without
relying on the old growth-dependent solid-
sawn timbers. [2]:3 As with other engineered
wood products, it reduces the overall
amount of wood used when compared to
solid sawn timbers by diminishing the
negative impact of knots and other small
defects in each component board.
Glulam has much lower embodied
energy than reinforced concrete and steel,
although of course it does entail more
embodied energy than solid timber.
However, the laminating process allows
timber to be used for much longer spans,
heavier loads, and complex shapes.
Glulam is two-thirds the weight of steel
and one sixth the weight of concrete – the
embodied energy to produce it is six times
less than the same suitable strength of
steel.[3] Glulam can be manufactured to a
variety of straight and curved
configurations so it offers architects artistic
freedom without sacrificing structural
requirements.[4] Wood has a greater tensile
strength relative to steel – two times on a
strength-to-weight basis – and has a
greater compressive resistance strength
than concrete.[5] The high strength and
stiffness of laminated timbers enable
glulam beams and arches to span large
distances without intermediate columns,
allowing more design flexibility than with
traditional timber construction. The size is
limited only by transportation and handling
constraints.[6]
Contents [hide]
1 Glulam versus steel 2 History 3 Sports structures 4 Glulam bridges 5 European Standards Organisation (CEN)
standards 6 See also
7 References 8 External links
§Glulam versus steel[edit]
A 2002 case study comparing energy use,
greenhouse gas emissions and costs for
roof beams found it takes two to three
times more energy and six to twelve times
more fossil fuels to manufacture steel
beams than it does to manufacture glulam
beams. It compared two options for a roof
structure of a new airport in Oslo, Norway
– steel beams and glulam spruce wood
beams. The life cycle greenhouse gas
emission is lower for the glulam beams. If
they are burned at the end of their service
life, more energy can be recovered than
was used to manufacture them. If they are
landfilled, the glulam beams result in
greater greenhouse gas emissions than
the steel beams. The cost of the glulam
beams is slightly lower than the steel
beams.[7]
§History[edit]
Glulam dome roofing the tower of the University of Zurich, built using the Hetzer system in 1911.
Richmond Olympic Oval intern view
One of the earliest still-standing glulam
roof structures is generally
acknowledged[8] to be the assembly room
of King Edward VI College, a school in
Bugle Street, Southampton, England,
dating from 1866, designed by Josiah
George Poole. The building is now the
Marriage Room of Southampton Register
Office.[9]
Two churches in Northumberland are now
thought to have the earliest extant uses:
Holy Trinity, Cambo (1842), and Holy
Trinity, Horsley (1844), and four 1850s
Merseyside churches also feature
laminated timbers: St Mary, Grassendale,
St Luke,Formby, St Paul, Tranmere and
Holy Trinity, Parr Mount, St Helens[citation
needed].
The first industrial patented use was
in Weimar, Germany. Here in 1872[8] Otto
Hetzer set up a steam sawmill and
carpentry business in Kohlstrasse.
Beginning in 1892, he took out a series of
patents. DRP No. 63018 was for a
ventilated timber floor deck that could be
tightened laterally after installation, to
compensate for shrinkage. Hetzer
continued to patent various ingenious
systems, but the first of these that could
be compared with subsequently
standardised horizontal glulam was DRP
No. 197773, dated 1906. This entailed
vertical columns which transitioned into
curved glued laminated eaves zones, and
then became sloped rafters, all in a single
laminated unit. Each component, bonded
under pressure, comprised three or more
horizontally arranged laminations.
In other words, the glulam portal frame
was born. In 1895, Hetzer moved his
company to Ettersburger Strasse, still in
Weimar. At the height of production, in
around 1917, he employed about 300
workers, and Müller includes a fine
engraving of the railway sidings and works
in 1921.
In 1909, the Swiss engineering
consultants Terner & Chopard[8] purchased
permission to use Hetzer's patent, and
employed glulam in a number of projects.
These included the former Hygiene
Institute, Zurich, 1911, now the main
building of the university, where the bell-
shaped roof dome is still to be seen.
The technology arrived in North America
in 1934 when Max Hanisch, Sr., who had
worked with Hetzer at the turn of the
century, formed a firm in Peshtigo,
Wisconsin to manufacture structural glued
laminated timber.
A significant development in the glulam
industry was the introduction of fully water-
resistant phenol-resorcinol adhesive in
1942. This allowed glulam to be used in
exposed exterior environments without
concern of gluline degradation. The first
U.S. manufacturing standard for glulam
was Commercial Standard CS253-63,
which was published by the Department of
Commerce in 1963. The most recent
standard is ANSI/AITC Standard A190.1-
02, which took effect in 2002.[2]:4
The roof of the Centre Pompidou-
Metz museum is composed of sixteen
kilometers of glued laminated timber. It
represents a 90-metre wide hexagon with
a surface area of 8,000 m². The glued
laminated timber motif forms hexagonal
wooden units resembling the cane-work
pattern of a Chinese hat.
§Sports structures[edit]
Sports structures are a particularly
suitable application for wide-span glulam
roofs. This is supported by the light weight
of the material, combined with the ability to
furnish long lengths and large cross-
sections. Prefabrication is invariably
employed and the structural engineer
needs to develop clear method statements
for delivery and erection at an early stage
in the design. The PostFinance Arena is
an example of a wide-span sports stadium
roof using glulam arches reaching up to
85 metres. The structure was built
in Berne in 1967, and has subsequently
been refurbished and extended.
The roof of the Richmond Olympic Oval,
built for speed skating events at the 2010
Winter Olympic Games in Vancouver,
British Columbia, features one of the
world's largest clearspan wooden
structures. The roof includes 2,400 cubic
metres of Douglas-fir lamstock lumber in
glulam beams. A total of 34 yellow-cedar
glulam posts support the overhangs where
the roof extends beyond the walls.[10]
§Glulam bridges[edit]
Sneek, The Netherlands. Heavy-traffic Accoya Glulam Bridge
Glulam bridge crossingMontmorency River, Quebec.
Pressure-treated glulam timbers or
timbers manufactured from naturally
durable wood species are well suited for
creating bridges and waterfront structures.
Wood’s ability to absorb impact forces
created by traffic and its natural resistance
to chemicals, such as those used for de-
icing roadways, make it ideal for these
installations. Glulam has been
successfully used for pedestrian, forest,
highway, and railway bridges. An example
in North America of a glulam bridge is
at Keystone Wye, South Dakota,
constructed in 1966–1967.
The Kingsway Pedestrian Bridge in
Burnaby, British Columbia, Canada, is
constructed of cast-in-place concrete for
the support piers, structural steel and
glulam for the arch, a post tensioned pre-
cast concrete walking deck, and stainless
steel support rods connecting the arch to
the walking deck.
§European Standards Organisation (CEN) standards[edit]
The following CEN standards are relevant
to the topic of glulam. They are used by all
of the countries that subscribe to the
European Committee for Standardisation:
EN 386 — Glued laminated timber —
Performance requirements and
minimum production requirements
EN 387 — Glued laminated timber —
Large finger joints — Performance
requirements and minimum production
requirements
EN 390 — Glued laminated timber.
Sizes. Permissible deviations
EN 391 — Glued laminated timber -
Delamination tests of glue lines
EN 392 — Glued laminated timber -
Shear test of glue lines
EN 408 — Structural timber and glued
laminated timber — Determination of
some physical and mechanical
properties
EN 1193 — Timber structures —
Structural timber and glued laminated
timber — Determination of shear
strength and mechanical properties
perpendicular to the grain
EN 1194 — Timber structures — Glued
laminated timber — Strength classes
and determination of characteristic
values
EN 14080 — Timber structures — Glued
laminated timber — Requirements
§See also[edit]
Fiberboard
Hardboard
I joist
Masonite
Medium-density fiberboard
Oriented strand board
Particle board
Plywood
Pressed wood
Laminated veneer lumber
Parallam
Timber framing
§References[edit]
1.Jump up^ A Guide To Engineered Wood Products, Form C800 (PDF). APA – The Engineered Wood Association. 2010. p. 7.
2.^ Jump up to:a b Product Guide, Form No. EWS X440 (PDF). APA – The Engineered Wood Association. 2008.
3.Jump up^ Timber Engineering Europe Ltd. Glulam beams
4.Jump up^ Canadian Wood Council Glulam5.Jump up^ Appendix: Mechanics of
Materials, Si Metric EditionFerdinand P.
Beer and E. Russell Johnston Jr.Appendix B Typical Properties of Selected Materials Used in Engineering
6.Jump up^ "About Glulam". American Institute of Timber Construction. Retrieved 3 February 2015.
7.Jump up^ FPInnovations A Synthesis of Research on Wood Products and Greenhouse Gas Impacts page 61
8.^ Jump up to:a b c Müller, Christian (2000). Laminated Timber Construction. Birkhäuser. ISBN 978-3764362676.
9.Jump up^ Leonard, A.G.K. (Spring 2008). "Josiah George Poole (1818–1897): Architect and Surveyor serving Southampton". Journal of the Southampton Local History Forum. Southampton City Council. pp. 19–21. Retrieved 2 June 2012.
10. Jump up^ Naturally:wood Richmond Olympic Oval
§External links[edit]
American Institute of Timber
Construction
APA – The Engineered Wood
Association
Glued Laminated Timber Association
(UK)
Glulam 'the naturally engineered
solution' from BKTS (UK)
Glulam Beam Repair/Reinforcement -
An article (Printed in STRUCTURE
magazine, Sep. 2006) by Gary W. Gray
P.E. and Paul C. Gilham P.E.
Timber Engineering Europe Glulam
Canadian Wood Council Glulam
Naturally:wood Engineered Wood
Glulam Romanian
Rosboro Glulam
http://www.wiehag.com/
[hide V T E
Wood products
Lumber/timber
Batten Beam Bressummer Cruck Flitch beam Flooring Joist Lath Molding Panelling Plank Plate Post Purlin Rafter Railroad ties Reclaimed Shingle Siding Sill Stud Timber truss
Treenail Truss Utility pole
Engineeredwood
Glued laminated timber veneer LVL parallel strand I-joist Fiberboard hardboard Masonite MDF Oriented strand board Particle board Plywood Structural insulated panel Wood-plastic composite lumber
Fuelwood
Charcoal biochar Firelog Firewood Pellet fuel Wood fuel
Fibers Cardboard Corrugated fiberboard Paper
Paperboard Pulp Pulpwood Rayon
Derivatives
Birch-tar Cellulose nano Hemicellulose Cellulosic ethanol Dyes Lignin Lye Methanol Pine tar Pitch Sandalwood oil Tannin Wood gas
By-products
Barkdust Black liquor Ramial chipped wood Sawdust Tall oil Wood flour Wood wool Woodchips
Historical Axe ties
Clapboard Dugout canoe Potash Sawdust brandy Split-rail fence Tanbark Timber framing Wooden masts
See also
Biomass Certified wood Destructive distillation Dry distillation Engineered bamboo Forestry List of woods Mulch Non-timber forest products Papermaking Wood drying Wood preservation Wood processing Woodworking