Lect1 material timber_edit-paklan

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TIMBER CONSTRUCTION Introduction

description

timber construction

Transcript of Lect1 material timber_edit-paklan

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TIMBER CONSTRUCTION

Introduction

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Introduction Traditional bldg

material

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Bldg industry largest consumer

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Offer advantages – easy workability + aesthetic appeal + resistance to shocks / vibrations

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M’sian usage limited to:- low cost construction- temporary structures- squatters / villages houses- concealed works / formworks

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Timber less popular in M’sia Due to prejudice, bad

workmanship, poor detailing.

Difficult to get popular species / higher cost than other materials

Present, Uniform Bldg Bye-Laws (UBBL) classify timber as temporary structures

Insurance companies not willing to insure against fire / premium very high

Difficult to get bank loan

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Timber more popular in West Usage in Europe /

N.America / Australia- large + prestigious structures- appreciate timber as bldg materials

Good workmanship / skill

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More advanced in timber technology glued laminated beams plywood box beam

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Availability + Cost M’sia still has plenty of

timber But only few species

popular – cengal, keruing, meranti

Most timber for export Difficult to get popular

species / higher cost than other materials

Govt, through M’sian Timber Industry Board to encourage other species

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Current situation Timber production geared towards export Only leftovers for local Prejudice towards timber – results in less

popular in urban areas Present, Uniform Bldg Bye-Laws (UBBL)

classify timber as temporary structures Insurance companies not willing to insure /

premium very high Difficult to get bank loan

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TIMBER AS STRUCTURAL

MATERIAL

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Structural Favourable strength to weight ratio “Bending strength” between 1/28 to 1/23

compared to mild steel “Stiffness” is low but compared to its weight, it is

relatively “stiff” (Extra structural members to compensate lack of stiffness will not greatly increase total weight)

Suitable for light to medium loaded low-rise building

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Strength Characteristics Strength characteristics indicate ability to

withstand load & potential as engineering an material

Malaysian timber categories into 7 groups:- SG1 to SG7- SG1 the strongest, SG7 the weakest

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Strength Group- commercially available M’sian timber

SG1 SG2 SG3 SG4 SG5 SG6 SG7

A) NATURALLY DURABLE

BALAU BELIAN BEKAK GIAM

CENGAL MATA ULAT KERANJI MERBAU

KEKATONG RESAK

B) REQUIRE TREATMENT

KEMPAS RED BALAU KAPUR KEDONDONG DURIAN GERONGGANG

MEMBATU K.SEMANGKOK KASAI KELEDANG JELUTONG PULAI

KULIM MERAWAN KERUING MACANG SESENDOK

TUALANG MEMPAUH RUBBERWOOD MEDANG

PUNAH MERANTI MERSAWA

RENGAS NYATOH TERAP

SIMPOH RAMIN MELANTAI

YELLOWMERANTI

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Fire resistance Combustible material

(thin boards easily burnt)

Large size more than 150mm have higher resistance to fire

Smaller sections can be protected with plasterboard, asbestos or fire retardant treatment

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Advantages of Timber Environmentally

friendly material Good appearance,

aesthetic appeal Low weight to

strength ratio Light, easy to handle,

easily joined Suitable for

prefabrication of components (reduce amount of site work)

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Dry construction, faster completion period

Good sound, thermal and electrical insulation property

Capacity to withstand shock / vibration

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Disadvantages Subjected to rot – dry

rot / wet rot Is a combustible

material Being a living

material, it is subjected to attack by insects / termite

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Traditional usage of timber Main structure of

Malay house made of “heavy hardwood” – such as “cengal”, “cengal mas”, “cengal batu” and “balau”

Floor of “balau”, “cengal”

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Walls made of “medium hardwood” – such as “meranti”

Colonial buildings – other species of timber such as “keruing” and “merbau” for structures

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Timber usage in brick buildings FLOOR – floor beams /

bearers, floor joist, floor boards

WALL – studs, wall panel / sheathing

CEILING – beams, ceiling joists

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ROOF – beams, rafters, trusses, purlins, battens

DOOR & WINDOW – frames, door panels, window leaves, sills

VERANDA – balusters, handrails, flooring, stairs, columns