Tutorial Presentation (2013-14)On

Timber as a Construction Material

Department of Civil Engineering

Prepared By:Paritosh Vyas (U11CE079)

Ganga Singh Chouhan(U11CE080)Kaushal Kumawat(U11CE081)

Dharmesh Kaithwas(U11CE082)

Timber: The Preface

Timber refers to wood used for construction works. In fact the word timber is derived from an old English word ‘Timbrian’ which means ‘to build’. A tree that yields good wood for construction is called ‘Standing Timber.’ After felling a tree, its branches are cut and its stem is roughly converted into pieces of suitable length, so that it can be transported to timber yard. By sawing, rough timber is converted into various commercial sizes like planks, battens, posts, beams etc. Such form of timber is known as converted timber.Timber was used as building material even by primitive man. Many ancient temples, palaces and bridges built with timber can be seen even today.

Source: Extension to EED, SVNIT

Source: Extension to EED, SVNIT

Timber as a cast and support for concrete casting of ;BeamsColumns SlabsFoundation

While Bamboo is used for scaffolding in Asian countries, Timber is occasionally used in scaffolds as platforms and in shoring

USES

Hadimba Temple, Manali

Source: KAASHTHA Timber Traders, Surat

Timber is frequently used in the frames of doors and windows.Type of Wood used:Shorea robustaVernacular name:सा�ल

In zones with cold climates and earthquake prone areas, structures are entirely constructed out of timber. These buildings have a distinct architecture and all structural elements are made of timber.

USES

Pragati Woodply, Icchanath, Surat

Source: KAASHTHA Timber Traders, Surat

Types of TimberThere are over 150 species of timber which are produced in India. Following are the chief varieties of timber trees which are used for engineering purposes in India:

Terminalia arjuna (अर्जु��न)

It is heavy and strong. It has such uses as beams, rafters, and posts.

Source: Google Images

Cedrus deodara (दे�वदे�र)

Source: Sample

Deodar is in great demand as building material because of its durability, rot-resistant character and fine, close grain, which is capable of taking a high polish. Its historical use to construct religious temples and in landscaping around temples is well recorded.

Tectona grandis(सा�ग)

Teak is often an effective material for the construction of both indoor and outdoor furniture. Teak's high oil content, high tensile strength and tight grain makes it particularly suitable for outdoor furniture applications. Teak is used extensively in India to make doors and window frames, furniture, and columns and beams in old type houses. It is very resistant to termite attacks.

Google Images

L Local Market Scenario - In the local market, most of

the timber is imported. Only inferior woods are from domestic sources.

- This is due to a ban on tree felling in India.

- Imported timber also serves better quality.

- This material is generally from African, South East Asian or Latin American countries.

- So high costs of importing and processing makes timber a lavish feature of construction.

Market Analysis

KAASHTHA Timber Mart, Nr. SOSYO Circle, Surat

- Once the material reaches port. It is transferrred to workshop by trucks (road ways).

- EOT ( electric overhead travelling ) crane lifts logs from store to the working zone.

- It travels over 2 rails on which motion is controlled by a powerful electric motor.

Workshop works

EOT CraneKAASHTHA Timber Mart

table wood cutterIts blade fitted on a table by making a Grove on it.Its generally used for rough cutting.

It’s a multi purpose machine which is used for cutting , grooving as well as filing.

KAASHTHA Timber Mart

KAASHTHA Timber Mart

c Cost Comparison

- The rate of timber in market is given in terms of cubic feet. ( varying from 650 to nearly 4000 )

- The cost of timber generally depends on the measure of the white part in the woody brown color of sample. This is a feature which is important for furniture wood.

- Its capability to bear compressive and tensile load.

- Resistance to the environmental conditions.

- Resistance to attack of insects.

- On the size of trunk of tree available.

- Non-uniformity in the internal texture of the timber.

Sr. no. Timber type Market rate

1 Burma teak 3800-4000

2 Tanzania teak 3100-3200

3 Valsadiya teak 2800-3000

4 Burma border teak 2000

5 Ghana teak 1450-1550

6 Sevan 1900

7 Saal teak 1200-1300

8 Pine 650

Local Market Rates of Timber

*the given rates are in cubic feet.

Defects in TimberAn irregularity or abnormality occurring in or on the surface of timberDefects are responsible for the following;

Reduction in StrengthLowering of DurabilityPoor Appearance Decay

Google Image Results

Classification of Defects

Natural Forces

Insects

Fungi

Conversion

Seasoning

Defects due to Natural Forces

Chemical Stain:Discoloration caused by external agency.

Rind Galls:Rind means bark and gall means abnormal growth. The peculiar curved swelling developed on the body of a tree at points where branches have been improperly cut off or removed.

Source: Ovara,Old Surat

Location: CED parking Lot

Defects due to Natural Forces

Coarse Grained:If the tree grows rapidly, the annual rings are widened. Such a timber possesses less strength.

Knots:The portion from which branch is removed receives nourishment for a long time and results in the formation of dark hard rings called knots. Continuity of wood fibers is broken by knots, they induce weakness.

KAASHTHA Timber Mart

Shakes:These are longitudinal separations in wood between the annual rings. These are cracks which partly or completely separate fibres of wood.

Defects due to Natural Forces

Twisted Fibres:These are also known as wandering hearts and are caused by the twisting of young trees by fast blowing wind. Unsuitable for sawing.

Location: CED Parking Lot

KAASHTHA Timber Mart

Defects Caused by InsectsBeetles Termites

Tunnel formation by larvae of beetle, bore holes of 2 mm diameter.Convert Timber to a flour like powder.Do not disturb the outer shell or cover

Live in colony and multiply fast. Bore tunnels without disturbing outer core. The Timber piece may look sound until completely hollowed.Good quality timber like Teak, Sal etc. can resist action of termites.

Google Images Google Images

Defects Due to Fungi

CHEMICAL DECOMPOSITION- GREYISH BROWN POWDER.-UNSEASONED OR IMPROPERLY SEASONED TIMBER EXPOSED TO RAIN AND WINDWELL SEASONED TIMBER USED FOR EXTERIOR OR UNDERGROUND WORK - COVERED BY TAR OR PAINT- PROTECTION AGAINST MOISTURE

DRY POWDERFORM-NO FREE CIRCULATION OF AIR SUCH AS IMPROPERLY VENTILATED BASEMENTS,ROOMS AND DAMPED SITUATIONLIKE KITCHEN TOILET ETC-ABSENCE OF SUNLIGHT,DAMPNESS,PRESENCE OF SAP,STAGNANT AIR AND WARMTH- FREE FROM SAP- COPPER SULPHATE

Wet Rot: Dry Rot:

KAASHTHA Timber Mart

Defects during Conversion

Chip Mark:This defect is indicated by a mark or sign placed on the finished surface of timber. Formed by Planing machine.

Diagonal Grain:Formed due to improper Sawing of timberIndicated by diagonal marks on straight grained surface of timber.

KAASHTHA Timber Mart

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Thank You.