Hello guys I am Pranish. In this blog you will get info about civil engineering so please feel free to share my posts Workshop unit:-4
Unit:-3
Timber
Defination:-
The wood obtained from fully grown free which is ready to use in engineering purpose is called timber. Eg frames of Door, and windows, Beam, wooden coloumn and scaffolding etc.
* Grain of wood section:-
It generally forms cell most of this cell are long, narrow. In longitiudnal direction. Along the trunk axis these long cells are called grain.
Strength of wood:-
Strength of wood is defined as the capacity of of timber to resist load.
There are normaly three types of strength:-
i)Tensile strength
ii)Comppresive strength
iii)Shear Strength
1)Tensile strength:-
It is the maximum tensile force that the timber can is more. per unit area safty resist Tensile strength in perpendicular dircation of grains.
eg sal 11.5 kN/mm² Chir 7.5 kN/mm²
Tensile strength (Ts) = Tensile Force (TF) / Cross section ArealA
2)Comppressive strength:-
It is the strength of timber that can recist Compressive load or force. Compressive strength is three times along the grain direction that along the perpendicular direction of grain
3)Shear strength
It is the strength of timber agnist shear load. Shear strength is greater at perpendicular to the grain direction.
Properties of timber
1)Strength
It depend upon the nature of a sell or and grain structure Timber can resist three
type of force. They are tensile force, compressive force and shear force.
2)Durablity
lt depend upon the nature of the chemical present in the cells and cell walls which are destructive to fungus growth and insects attack.
3)Density
It depends upon cell size and amount of cell present in per unit volume.
4) Hardness
Hardness is the properties to which it can resist direct Impact. It depond upon structure of cell wall.
5) Lightness
Most of the softwood is made up of thin walled cell which gives the light to the wood.
6)Texture
These refers to size and quality of the cells.
7)Grain
These refers to the direction of cell pattern Egg straight sloping diagonal etc.
*Uses of timber:-
1)Temporary structure
-Scaffolding
-Formwork
-Shuttering
2)Bulding construction :-
-structural components (members): Pillar, Beam
-Opening → Door, window ventilation
-Staircase
-Roof, floor
-Partition wall
3)Furnitures:- Table, sofa, bed, Cupboard
4) Decoration purpose.
5) Musical Instrument:- Madal, guitar, violen.
6)Transportation purpose:- Boat
7)Sports:- Cricket materiale, hockey materials
8)Tools
9) Agricultural tools
10)Bridges
11)Electric poles
Advantage of timber:-
i)It is strong and durable.
ii)It is a bad conductor of electricity.
iii)It is easy to work.
iv)It is easy to paint.
v)It is easy to transfer from place to place. vi)It is light in weight.
vii)It is rust-free and sound proof.
viii)It is easily avilable in locality
ix)Itcan be reuse.
x)It is good resistance against heat.
Disadvantage
i)It is expensive nowadays.
ii)It can caught fire easily and is combustable
iii) Unseasoned timber can be attacked by insects.
iv)It can't rist resist heavy load.
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