The woods that is available for construction is called as timber. the timber as a construction material is less demanded in civil engineering field.
» Uses of Timber in Construction:-
Timber is used as sleepers, coaches in railway construction.Timber used in making furniture.Timber used in the formwork construction.Timber used in making trusses, rafters, piles, arches , partition walls, poles, beams etc
1. Colour and Appearance of good timber: A good timber material must possess dark colour. Low strength of the timber can be understood from its light colour. For this the wood taken must be from the hard wood. This hard wood has to be free from the sap. Uniformity in colour has to be possessed by the wood.
In appearance, the wood must have a hard and shiny surface. Once the timber is planed, the surface must be smooth and bright in colour. Having a dull appearance shows all signs of defects in it.
2. Defects: The timber used for the construction has to be free from defects like blemishes, flaws, shakes, knots etc.
3. Timber Resistance and durability:The timber has to be resistant towards the action of fungi, insects, alkalies, physical agencies and mechanical agencies.
4. Weight of Timber: The weight and the density of timber have to be more. This will reflect a sound timber material.
5. Fibres in Timber: The timber is made of fibres in thousands. These fibres have to be straight and compact in nature. All the fibres within have to be firm and adhesive to each other.
6. Elasticity of Timber: Elasticity property of the timber material is essential for the construction of goods, trusses, shafts etc.
7. Mechanical Wear of Timber: The mechanical wear or abrasion resistance of the timber will help it to stay long when used in high traffic areas, as pavements or wooden floors.
8. Hardness of Timber: The resistance against penetration of any other material into the timber is gained by the hardness property. The chemicals that are present in the heart wood will impart hardness to the material. The density of the wood also defines the hardness of the timber material.
9. Shock Resistance of Timber: The timbers have to be resistant towards undesirable shocks. This is gained by shock resistance property.
10. Shape of Timber: All the preparation process of the timber must not bring any change in shape of the material. It must not undergo any change in shape even after it is subjected to structural use. Change in shape means either warping, expanding, splitting or swelling of the timber wood.
11. Timber with Good Finish and Polish:The timber is finally subjected to final finish and polish. The material must have the ability to take good polish when used in the application of window doors, furniture items. The surface of the timber must have the ability to receive the paint properly.
12. Odour and Sound: The freshly cut wood will have a sweet smell and an unpleasant smell shows the timber have started to decay. A ringing sound made by two pieces of wood will show that it is sound wood.
13. Strength of Timber: A good quality wood must possess strength to carry all types of loads. It must carry all the direct, shear and bending stress in order to behave as a sound beam, column, post, joist and a rafter.
14. Permeability of Timber: The permeability in case of timber, is the possibilities of penetration of water. Good quality timber must be impermeable in nature. The permeability is more along the direction of fibre orientation than on perpendicular direction.
15. Structure of Timber: The timber structure has to be uniform in nature. The timber cross sections consist of annular rings and medullary rays. The annular rings must be regular for good quality wood. This will have hard and compact medullary rays
16. Workability of Timber: Good timber must be able to cut easily, planed and smoothened easily. During the process of sawing, the teeth must not undergo clogging.
» Uses of Timber in Construction:-
Timber is used as sleepers, coaches in railway construction.Timber used in making furniture.Timber used in the formwork construction.Timber used in making trusses, rafters, piles, arches , partition walls, poles, beams etc
Qualities of good timber in construction :-
1. Colour and Appearance of good timber: A good timber material must possess dark colour. Low strength of the timber can be understood from its light colour. For this the wood taken must be from the hard wood. This hard wood has to be free from the sap. Uniformity in colour has to be possessed by the wood.
In appearance, the wood must have a hard and shiny surface. Once the timber is planed, the surface must be smooth and bright in colour. Having a dull appearance shows all signs of defects in it.
2. Defects: The timber used for the construction has to be free from defects like blemishes, flaws, shakes, knots etc.
3. Timber Resistance and durability:The timber has to be resistant towards the action of fungi, insects, alkalies, physical agencies and mechanical agencies.
4. Weight of Timber: The weight and the density of timber have to be more. This will reflect a sound timber material.
5. Fibres in Timber: The timber is made of fibres in thousands. These fibres have to be straight and compact in nature. All the fibres within have to be firm and adhesive to each other.
6. Elasticity of Timber: Elasticity property of the timber material is essential for the construction of goods, trusses, shafts etc.
7. Mechanical Wear of Timber: The mechanical wear or abrasion resistance of the timber will help it to stay long when used in high traffic areas, as pavements or wooden floors.
8. Hardness of Timber: The resistance against penetration of any other material into the timber is gained by the hardness property. The chemicals that are present in the heart wood will impart hardness to the material. The density of the wood also defines the hardness of the timber material.
9. Shock Resistance of Timber: The timbers have to be resistant towards undesirable shocks. This is gained by shock resistance property.
10. Shape of Timber: All the preparation process of the timber must not bring any change in shape of the material. It must not undergo any change in shape even after it is subjected to structural use. Change in shape means either warping, expanding, splitting or swelling of the timber wood.
11. Timber with Good Finish and Polish:The timber is finally subjected to final finish and polish. The material must have the ability to take good polish when used in the application of window doors, furniture items. The surface of the timber must have the ability to receive the paint properly.
12. Odour and Sound: The freshly cut wood will have a sweet smell and an unpleasant smell shows the timber have started to decay. A ringing sound made by two pieces of wood will show that it is sound wood.
13. Strength of Timber: A good quality wood must possess strength to carry all types of loads. It must carry all the direct, shear and bending stress in order to behave as a sound beam, column, post, joist and a rafter.
14. Permeability of Timber: The permeability in case of timber, is the possibilities of penetration of water. Good quality timber must be impermeable in nature. The permeability is more along the direction of fibre orientation than on perpendicular direction.
15. Structure of Timber: The timber structure has to be uniform in nature. The timber cross sections consist of annular rings and medullary rays. The annular rings must be regular for good quality wood. This will have hard and compact medullary rays
16. Workability of Timber: Good timber must be able to cut easily, planed and smoothened easily. During the process of sawing, the teeth must not undergo clogging.
No comments:
Post a Comment