k3 kayu-application & product -...
TRANSCRIPT
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FKA –UTM
Department of Structures and Materials, Faculty of Civil Engineering
UTM
1
TIMBERTIMBER
Lecturer:
Prof. Dr. Mohammad IsmailFaculty of Civil Engineering, UTM-Skudai,
Johor Darul Ta’zim,
MALAYSIA
December 6, 2013
Room : C09-313
Tel : 07 - 5531688
5. Timber Application, Products
and their use
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FKA –UTM
Department of Structures and Materials2
STRUCTURAL APPLICATION
Marine Work
• Timber use for wharves, piers, sheet piling and cofferdam even though many of these application has been replaced by steel
• For groynes still economic to use timber
• Problem associated with marine work
� Impact, Abrasion, Infestation by marine borers
� Fungal attack, Erosion by chemical action or salt
� Wave action, Dimensional movement caused by differential temperature
• Properties Required
� High density, closeness of grain and resistance to impact, natural durability and wear resistance
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Department of Structures and Materials3
Heavy Construction WorkTimber still used for heavy constructional purposes where availability and cost of materials are favourable. Among others
Pylons, Gantries, Bridges, Shoring and abutments
Main ProblemImpact or accidental loading, infestation, chemical and fungal attack, dimensional movement
Properties RequiredHigh density, closeness of grain and resistance to impact, resistance to acidity, alkalinity and others
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Department of Structures and Materials4
Medium/Light
Construction Work
Roof trusses, partitions,
screens, floors and wall
panels
Properties Required
Reinforced any resistance to fire or rate of flame
Main Problem
Resistance to insect and fungal attack, minimum
dimensional change
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FKA –UTM
Department of Structures and Materials, Faculty of Civil Engineering
UTM
5
Drawback of Solid timber
• Inherent anisotropy
• Many natural defects
• Limited size in (section and length)
• Difficulty of drying
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FKA –UTM
Department of Structures and Materials, Faculty of Civil Engineering
UTM
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SHEET MATERIALS
Range of sheet, board or panel products
includes veneer and core plywoods,
chipboard and flakeboards and a
variety of fibreboards
VERNEER PLYWOOD
• Correct name for plywood defined in BS 6566: Part 2
• All the plies are made of veneers oriented with their plane parallel to the surface of the panel
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FKA –UTM
Department of Structures and Materials, Faculty of Civil Engineering
UTM
7
• Direction of the verneer grain in a ply is at right angles to the direction in the immediately adjacent plies
• There are odd number of plies
• The glues used depend on the intended use of the plywood,
� urea formaldehyde for interior and phenol formaldehyde for exterior
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FKA –UTM
Department of Structures and Materials, Faculty of Civil Engineering
UTM
8
VERNEER PLYWOOD
• Initial cold press may be used before the assembly is put into a hot press, where the glue cures
• Cured panels cooled and trimmed to finished size
• Verneer plywood is generally graded in terms of appearance, durability and bond. According to MS 3.22, 1974, plywood graded to 1, 2 and 3
• Local timber used for plywood:
� Kayu Kapur, Keruing, Mengkulang, Meranti dan Mersawa
• Size (L) 1.8m, 2.4, 2.7 and 3. (W) 600mm, 900 and 1.2m. (T) 2.7-50mm
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FKA –UTM
Department of Structures and Materials, Faculty of Civil Engineering
UTM
9
CORE PLYWOOD
• Commonly referred to as blockboard or laminboard
• Manufactured from strips of solid timber, normally each-glued together to form a solid slab of material
• Normally used in interior applications and have only limited application in construction such as panelling, partitions and door blank
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FKA –UTM
Department of Structures and Materials, Faculty of Civil Engineering
UTM
10
PARTICLEBOARDS
• Commonly referred to wood chipboard or
recently oriented strand board (OSB) and
cement bonded particle board
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FKA –UTM
Department of Structures and Materials, Faculty of Civil Engineering
UTM
11
Chipboard
• Raw material may be solid wood, such as sawmill
offcuts, forest thinnings or logging waste
• or wood residues such as planer shavings or sawdust
• Solid wood is fed into a chipper which cuts the required
sizes and shape of particle
• The chips are then mixed with resin, usually urea
formaldehyde and then formed into a mat on a flat plate,
the oriented totally at random
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FKA –UTM
Department of Structures and Materials, Faculty of Civil Engineering
UTM
12
Oriented strand board
• Development of waferboard made by cutting small roundwood logs or plywood peeler cores into large flakes which are less than 1 mm thickness
• OSB the flakes are trimmed into rectangular pieces at least twice as long as they are broad, length 75mm or more
• Manufacturing process nearly similar to chipboard
• Application - similar to plywood (wall sheathing) except in highly stressed zones
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FKA –UTM
Department of Structures and Materials, Faculty of Civil Engineering
UTM
13
Cement bonded particleboards
� Small particles of wood blended with cement, water and chemical admixtures
� Wet mixture is then spread to thickness and held in a light press until the cement sets
• Cement bonded, wood content quite low
• Density much higher
• High resistance to fire
• Further information in BS 5669
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FKA –UTM
Department of Structures and Materials, Faculty of Civil Engineering
UTM
14
FIBREBOARDS
• Wood tissue reduced to the basic fiber, eliminate all trace of structure, defect and anistropy
• The product has exceptionally fine texture throughout, with very smooth surface finish
• According to BS 1142, fiberboard not normally use for structural purpose but for internal fitting and finishing and insulation
• Marketed as a replacement for solid timber mouldings in finishing joinery since its fine texture makes it readily machinable to a range of profiles
• Its smooth surface gives an excellent substrate for painting and it is more stable in changing environments
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FKA –UTM
Department of Structures and Materials, Faculty of Civil Engineering
UTM
15
GLUED LAMINATED SECTION
•“Glulam,” or glue-laminated timber, introduced in Europe
in the late nineteenth century, consists of sawn timber
laminations bonded with an adhesive so that the grain of
all laminations runs parallel with the long direction
•BS 4978 for
softwood and
• BS 5756 for
tropical
hardwood
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FKA –UTM
Department of Structures and Materials, Faculty of Civil Engineering
UTM
16
“Glulam,” or glue-laminated
timber, introduced in Europe
in the late nineteenth century,
Consists of sawn timber
laminations bonded with an
adhesive so that the grain of
all laminations runs parallel
with the long direction
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FKA –UTM
Department of Structures and Materials, Faculty of Civil Engineering
UTM
17
Timber sections are kiln dried
to a moisture content of about
12%, after which they are
finger jointed to a required
lengths
Lamination thickness may
vary from 10 mm – 50 mm
Thinner lamination enabling
tighter bends to be produced
and giving greater strength
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FKA –UTM
Department of Structures and Materials, Faculty of Civil Engineering
UTM
18
Manufactured in various sizes and shapes; curved, tapered circular, and spiral-shaped members
Glulam is stronger in longitudinal direction and weaker in the tranverse direction
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FKA –UTM
Department of Structures and Materials, Faculty of Civil Engineering
UTM
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Advantage:
flexibility of shape and size – straight, curved, atches or frame and enabling clear spans in excess of 50m. Appearance warm and attractive
Predictable in fire as solid timber. Additional protection in fire may be obtained by surface treatments, such as clear intumescent varnishes
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FKA –UTM
Department of Structures and Materials, Faculty of Civil Engineering
UTM
20
Allowable strength properties superior than those of
sawn timber
Commonly used for purlins, joists, headers, beams,
and truss members. Also in the design of pedestrian
and highway bridges
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FKA –UTM
Department of Structures and Materials, Faculty of Civil Engineering
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21
1. Define fiber saturation point and equilibrium
moisture content
2. Explain the effects of moisture content on the
strength characteristics of wood
3. What is clear wood
4. Explain the decay and destruction of wood
5. Define growth ring, check, grain and slope grain
6. Explain seasoning and treatment of timber
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FKA –UTM
Department of Structures and Materials, Faculty of Civil Engineering
UTM
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