TIMBER DETAILS, Varity, Categories, .pptx

TIMBER

1. timber MODULE : MATERIAL MODULE CODE : F45TOOM10

2. CONTANTS Introduction Identifications of Timber Uses of Timber Alternative materials of Timber Defects of Timber Preservation of Timber Seasoning of Timber Defects due to seasoning Storage of Timber Examples of Timber structure

3. 3 TIMBER : The wood which is suitable or fit for engineering construction or engineering purpose is called timber. WOOD: The organic matter obtained from trees is called wood. LUMBER : The sawed wood meant for Construction in the form of boards is called lumber. INTRODUCTION

4. Identifications of Timber General Properties Color : a darker color in wood indicates greater durability. Odor : it is present only on freshly cut trees. Density : densest woods are generally the strongest. Structure : The structure should be uniform. Toughness : A good timber should be tough (i.e.) capable of offering resistance to shocks due to vibration.

5. Appearance : A freshly cut surface of timber should exhibit hard and of shining appearance. Defects: A good timber should be free from series defects such as knots, flaws, shakes etc Durability: A good timber should be durable and capable of resisting the action of fungi, insects, chemicals, physical agencies, and mechanical agencies. Identifications of Timber

6. Swelling: It is the capacity of wood to increase both its linear and volumetric dimensions when it absorbs water. Fire resistance: A dense wood offers good resistance to fire. Hardness: A good timber should be hard. Shrinkage: This is the reduction in leaner and volumetric dimensions in drying of place only when hygroscopic moisture evaporates. Identifications of Timber

7. Shape: A good timber should be capable of retaining its shape during conversion or seasoning Sound: A good timber should give a clear ringing sound when struck Strength: A good timber should be sufficiently strong for working as structural member such as joist, beam, rafter etc. Identifications of Timber

8. USES OF TIMEBR : Timber is used in: 1.Building construction 2.Construction of house posts 3.Construction of beams 4.Construction of rafters 5.Construction of bridges

9. 9 6.Construction of piles, poles and railway sleepers,

10. Plastic Timber Isn’t wood at all, but a 100 per cent recyclable material that is made of recycled plastic made to look like genuine wood Alternative Timber Examples

11. 2. Fibre -reinforced composite timber Involves a complex mix of refined, blended and compounded natural fibres -makes use of rice husk, rice hull and plastic -actually hollow Alternative Timber Examples

12. 2. Wood-plastic composites - made of: * wood fibres * wood flour * thermoplastics -Cannot be recycled Alternative Timber Examples

13. DEFECTS OF TIMBER

14. DEFINE DEFECTS IN TIMBER A DEFECT IS AN IRREGULARITY OR ABNORMALITY OCCURING IN OR ON WOOD WHICH IS RESPONSIBLE FOR ITS STRENGTH REDUCTION LOWERING OF DURABLITY LOWERING OF UTILITY POOR APPERANCE DECAY

15. CLASSIFICATIONS OF DEFECTS (CAUSED DUE TO) NATURAL FORCES INSECTS FUNGI CONVERSION SEASONING

16. DEFECTS DUE TO NATURAL FORCES CHEMICAL STAIN KNOTS SHAKES RIND GALLS UPSETS BURLS TWISTED FIBRES

17. CHEMICAL STAIN :- THE WOOD IS SOMETIMES DISCOLOURED BY THE CHEMICAL ACTION CAUSED WITH IT BY SOME EXTERNAL AGENCY.THIS IS KNOWN AS CHEMICAL STAIN. RIND GALLS :- THE RIND MEANS BARK AND GALL INDICATES ABNORMAL GROWTH.HENCE PECULIAR CURVED SWELLING FOUND ON THE BODY OF TREE ARE KNOWN AS RIND GALL.THEY DEVELOP AT POINTS FROM WHERE BRANCHES ARE IMPROPERLY CUT OFF OR REMOVED.THEY ARE RARELY FOUND IN A TREE AND THE TIMBER IN THIS PART IS VERY WEAK AND NOT DURABLE.

18. KNOTS :- THESE ARE THE BASES OF BRANCHES OR LIMBS WHICH ARE BROKEN OR CUT OFF FROM THE TREE.THE PORTION FROM WHICH THE BRANCH IS REMOVED RECIEVES NOURISHMENT FROM THE STEM FOR A PRETTY LONG TIME AND IT ULTIMATELY RESULTS IN FORMATION OF DARK HARD RINGS WHICH ARE KNOWN AS KNOTS.AS CONTINUITY OF WOOD FIBRES ARE BROKEN BY KNOTS,THEY FORM A SOURCE OF WEAKNESS

19. DEAD WOOD :- THE TIMBER WHICH IS OBTAINED FROM DEAD STANDING TREES CONTAINS DEAD WOOD.IT IS INDICATED BY LIGHT WEIGHT AND REDDISH COLOUR . SHAKES :- THESE ARE LONGITUDINAL SEPERATIONS IN WOOD BETWEEN THE ANNUAL RINGS.THESE ARE CRACKS WHICH PARTLY OR COMPLETELY SEPARATE FIBRES OF WOOD.THE SEPERATIONS MAKE THE WOOD UNDESIRABLE WHEN APPERANCE IS IMPORTENT

20. TYPES OF SHAKES STAR SHAKES:- THESE ARE CRACKS WHICH EXTEND FROM BARK TOWARDS THE SAP WOOD.THESE ARE USUALLY CONFINED UPTO THE PLANE OF SAP WOOD.THESE ARE WIDER ON OUTSIDE ENDS AND NARROWER ON INSIDE ENDS.THEY ARE USUALLYFORMED DUE TO EXTREME HEAT OR SEVERE FROST DURING THE GROWTH OF TREE CUP SHAKES:- IT APPEARS AS CURVED SPLIT WHICH PARTLY OR WHOLLY SEPERATES ANNUAL RINGS FROM ONE ANOTHER.IT IS CAUSED DUE TO EXCESSIVE FROST ACTION ON SAP PRESENT IN THE TREE ESPECIALLY WHEN THE TREE IS YOUNG

21. HEART SHAKES :- THESE CRACKS OCCUR IN CENTRE OF CROSS-SECTION OF TREE AND THEY EXTEND FROM PITH TO SAP WOOD IN DIRECTION OF MEDULLARY RAYS.THESE CRACKS OCCUR DUE TO SHRINKAGE OF INTERIOR PART OF TREE WHICH IS APPROACHING MATURITY.THE HEART SHAKE DIVIDE THE TREE CROSS-SECTION INTO TWO OR FOUR PARTS. RING SHAKES :- WHEN CUP SHAKES COVER THE ENTIRE ,THEY ARE KNOWN AS RING SHAKES

22. TWISTED FIBRES :- THESE ARE KNOWN AS WANDERING HEARTS AND CAUSED BY TWISTING OF YOUNG TREES BY FAST BLOWING WIND.THE TIMBERS WITH TWISTED FIBRES IS UNSUITABLE FOR SAWING UPSETS :- THESE INDICATE WOOD FIBRES WHICH ARE INJURED BY CRUSHING OR COMPRESSION.THE UPSETS ARE MAINLY DUE TO IMPROPER FELLING OF TREE AND EXPOSURE OF TREE IN ITS YOUNG AGE TO FAST BLOWING WIND BURLS :- THEY ARE PARTICULARLY FORMED WHEN A TREE RECIEVES SHOCK OR INJURY IN ITS YOUNG AGE.DUE TO ITS INJURY,THE GROWTH OF TREE IS COMPLETELY UPSET AND IRREGULAR PROJECTIONS APPEAR ON THE BODY OF TIMBER

23. DEFECTS DUE TO FUNGI BLUE STAIN BROWN ROT DRY ROT HEART ROT WET ROT WHITE ROT

24. BLUE STAIN :- THE SAP OF WOOD IS STAINED TO BLUISH COLOUR BY THE ACTION OF CERTAIN TYPE OF FUNGI BROWN ROT :- THE TERM ROT IS USED TO INDICATE DECAY OR DISEASE OF TIMBER,THE FUNGI OF CERTAIN TYPE REMOVES CELLULOSE COMPOUNDS FROM WOOD AND HENCE WOOD ASSUMES THE BROWN COLOUR WHITE ROT :- IT IS JUST OPPOSITE OF BROWN ROT.IN THIS CERTAIN TYPE OF FUNGI ATTACK LIGNIN OF WOOD AND WOOD ASSUMES THE APPEARANCE OF A WHITE MASS CONSISTING OF CELLULOSE COMPOUNDS

25. HEART ROT :- THIS IS FORMED WHEN BRANCH HAS COME OUT OF THE TREE.IN SUCH CASE,THE HEART WOOD IS EXPOSED TO ATTACK OF ATMOSPHERIC AGENTS.ULTIMATELY THE TREE BECOMES WEAK AND IT GIVES HOLLOW SOUND WHEN STRUK WITH HAMMER WET ROT:- SOME KIND OF FUNGI CAUSEDCHEMICAL DECOMPOSITION OF WOOD OF TIMBER AND IN DOING SO CONVERT TIMBER INTO GREYISH BROWN POWDER.IT IS KNOWN AS WET ROT. DRY ROT :- SOME TYPES OF FUNGI FEED ON WOODS AND DURING FEEDING THEY ATTACK ON WOOD AND CONVERT IT INTO DRY POWDER FORM.THIS IS KNOWN AS DRY ROT.

26. DEFECTS DUE TO INSECTS (CAUSED BY) BEETLES MARINE BOARERS TERMITES

27. DEFECTS DUE TO INSECTS DEFECTS CAUSED BY BEETLES THEY FORM PIN HOLES OF SIZE ABOUT 2MM DIA IN WOOD TUNNEL FORMATION IS DONE IN SAP WOOD BY LARVAE OF BEETLE CONVERSION OF TIMBER INTO FLOUR LIKE POWDER THEY DO NOT DISTURB OUTER SHELL OR COVER Flour like powder

28. DEFECTS DUE TO MARINE BOARERS BOARS THEY ARE FOUND IN SALTY WATER THEY FORM TUNNELS OR BORES TO TAKE SHELTERS DIAMETER AND LENGTH OF HOLES ARE AS HIGH AS 25MM AND 60 MM RESPECTIVELY AFFECTED WOOD LOOSES ITS COLOUR AND STRENGTH NO TIMBER IS COMPLETELY IMMUNE FROM ATTACK OF MARINE BOARERS

29. DEFECTS CAUSED BY TERMITES LIVES IN COLONY AND VERY FAST IN EATING AWAY THE WOOD FROM CORE OF CROSS-SECTION. MAKES TUNNELS IN DIFFERENT DIRECTIONS AND USUALLY NOT DISTURB THE OUTER SHELL OR COVER. THE TIMBER PIECE ATTACKED BY TERMITES MAY LOOK SOUND UNTILL IT COMPLETELY FAILS FEW GOOD TIMBERS LIKE TEAK,SAL,ETC CAN RESIST THE ACTION OF TERMITES

30. DEFECTS DUE TO CONVERSION CHIP MARK DIAGONAL GRAIN TORN GRAIN WANE

31. DEFECTS DUE TO CONVERSION CHIP MARK :- THIS DEFECT IS INDICATED BY MARK OR SIGNS PLACED ON FINISHED SURFACE OF TIMBER.THEY MAY BE FORMED BY PLANING MACHINE WANE :- THIS DEFECT IS DENOTED BY PRESENCE OF ORIGINAL ROUNDED SURFACE ON MANUFACTURED PART OF TIMBER

32. DIAGONAL GRAIN :- THE DEFECT IS FORMED DUE TO IMPROPER SAWING SAWING OF TIMBER.IT IS INDICATED BY DIAGONAL MARKS ON STRAIGHT GRAINED SURFACE OF TIMBER TORN GRAIN TORN GRAIN :- DEFECT CAUSED WHEN A SMALL DEPRESSION IS FORMED ON A FINISHED SURFACE OF TIMBER BY FALLING A TIMBER OR SO

33. Preservation of Timber It means protecting from fungi and insects attack so that its life is increased. The following are the widely used: 1.Tar Treatment: Hot coal tar is applied to timber with brush. The coating of tar protects the timber from the attack of fungi and insects. It is a cheapest way of protecting timber. Main disadvantage Appearance is not good after tar is applied

34. 2. Paints Treatment: Two to three coats of oil paints are applied on clean surface of wood. The paint protects the timber from moisture. The paint is to be applied from time to time. Paint improves the appearance of the timber. Solignum paint is a special paint which protects the timber.

35. 4. Creosote oil treatment: Creosote oil is obtained by distillation of coal tar. The seasoned timber is kept in an air tight chamber and air is exhausted. Then creosote oil is pumped into the chamber at a pressure of 0.8 to 1.0 N/mm2 at a temperature of 50°C. After 1 to 2 hours timber is taken out of the chamber. Following paints are used to save timber from fire. Diammonium phosphate, Mono ammonium phosphate, Mono magnesium phosphate, Phosphoric acid.

36. And also Immersion – in this method the materials are immersed in the preservative solution for penetration Pressure and vacuum treatment Hot and cold open tank treatment Charring - surface is burnt and the burnt part act as a protective coat

37. 37 SEASONING OF TIMBER: As fresh timber which is obtained from trees contains about 30 to 40 % sap or moisture. This sap is very harmful for the life of a timber. Therefore, it is necessary to remove that sap by applying some special methods. All those methods which are used for removing the sap from timber are collectively termed as seasoning of timber.

38. 38 Advantages of seasoned timber: It has reduced weight, It is strong and durable, It has resistance to decay or rot, It takes high polish, It is easier to work, Its life is more.

39. 39 Types of Timber Seasoning : The main types of timber seasoning are as under. Natural Seasoning, Artificial Seasoning, (a) Kiln Seasoning, (b) Chemical Seasoning, (c) Electric Seasoning, (3) Water Seasoning ,

40. 40 (1) Natural Seasoning: In the air seasoning or natural seasoning or natural drying, seasoning of timber, timber is dried by direct action of air, wind and sun. In this method, the timber logs are arranged one over the other, keeping some space or distance between them for air circulation of fresh air. Generally this type of seasoning requires few months to over a year, this is very slow process.

41. 41

42. Air Seasoning Advantages No expensive equipment needed Small labour cost once stack is made Environmentally friendly- uses little energy Disadvantages Slow drying rate Large area of space required for a lot of timber Only dries the timber to approximately 20% M.C. so leaving it open to some insect and fungal attacks while it is only suitable for outdoor joinery

43. (2) ARTIFICIAL SEASONING (a) Kiln Seasoning, (b) Chemical Seasoning, (c) Electric Seasoning, 43

44. 44 (a) Kiln Seasoning : In kiln seasoning timber is placed in a chamber with some special heating arrangement. In this process one thing should be kept in mind that heating system should be under control, other wise timber will be crack or wrap. The time required for this seasoning is 3 to 12 days. This is quick process.

45. Kiln Seasoning 45

46. Kiln Seasoning Advantages Quicker due to higher temperatures, ventilation and air circulation Achieve a lower moisture content Defects associated with drying can be controlled Allows more precise rates of drying for various timber species and thickness of boards Disadvantages Is expensive Requires supervision by a skilled operator Uses a lot of energy

47. 47 (b) Chemical Seasoning : In chemical seasoning carbon dioxide, ammonium carbonate or urea are used as agents for seasoning, those are applied in dry state, the inter surface of timber dries first than outer side. This ensures uniform seasoning. The time required for this seasoning is 30 to 40 days.

48. 48 (c) Electric Seasoning: In this method electric current is passed through the timber logs. The time required for this seasoning is 05 to 08 hours.

49. Electric Seasoning 49

50. 50 (3) Water Seasoning: In water seasoning, timber logs are kept immersed whole in the flowing water. The sap present in timber is washed away. After that logs are taken out from water and are kept in open air, so water present in timber would be dried by air. The time required for this type of seasoning is 2 to 4 weeks.

51. DEFECTS DUE TO SEASONING TWIST CUP BOW SPRING SPLIT HONEY COMBING

52. DEFECTS DUE TO SEASONING BOW :- THIS DEFECT IS INDICATED BY CURVATURE FORMED IN DIRECTION OF LENGTH OF TIMBER CUP :- THIS DEFECT IS INDICATED BY CURVATURE FORMED IN TRANSVERSE DIRECTION OF TIMBER

53. CHECK :- A CRACK WHICH SEPERATES FIBRES OF WOOD.IT DOES NOT EXTEND FROM ONE END TO THE OTHER SPLIT:- WHEN CHECK EXTENDS FROM ONE END TO OTHER,IT IS KNOWN AS A SPLIT SPLIT CHECK

54. TWIST :- WHEN A PIECE OF TIMBER HAS SPIRALLY DISTORTED ALONG ITS LENGTH,IT IS KNOWN AS A TWIST HONEY-COMBING :- DUE TO STRESS DEVOLOPED DURING DRYING,VARIOUS RADIAL AND CIRCULAR CRACKS DEVELOP IN THE INTERIOR PORTION OF TIMBER,WHICH RESEMBLES WITH HONEY-COMB TEXTURE HONEY-COMB STRUCTURE

55. STORAGE OF TIMBER Place all stored material in well-drained locations and keep these locations free from weeds and rubbish UNTREATED TIMBER AND PILING Open stack the materials at least 12 in (300mm) above the ground. Pile the materials, so water can run off them to prevent warping. Protect the materials with durable waterproof covering approved by the engineer. TREATED TIMBER AND PILING Close stack treated materials at least 12 in (300mm) above the ground and pile them to prevent warping TIMBER AFTER FEBRICATION Store this timber in covered storage, so the members do not change dimensions before they are assembled

56. EXAMPLES TIMBER

57. Center Pompidou - Metz By Shigeru Ban Architects Europe

58. The wooden observation tower at Helsinki Zoo in Finland was the winning design in a competition held for architectural students of Helsinki University of Technology. Situated on a small island just outside the city, and built on one of its highest hills, it provides visitors to the zoo with panoramic views over the sea and surrounding area. LUSAS Civil & Structural was used in the design and analysis to prove the safety and structural behaviour under imposed loading. Wooden Tower, Helsinki Zoo By the A rchitectural Students of Helsinki University of Technology.

59. Yusuhara Wooden Bridge Museum, Takaoka-gun, Kochi Prefecture, Japan by Kengo Kuma & Associates

60. Richmond Olympic Oval British Columbia, Canada

61. Sneek , The Netherlands. Heavy-traffic Accoya Glulam Bridge

62. THANK YOU FOR WATCHING!