How to calculate cutting length of diamond stirrups,Cutting length of diamond stirrups,in this topic we know about how to calculate cutting length of diamond stirrups. Another word stirrups is also known as ring or shear reinforcement. It is closed loop of reinforcements used to hold the main reinforcement in RCC structure like column and beam.
The rhombus shape diamond Ring used in column provide lateral support to the the main bar against buckling it is used at proper interval to beam and column to prevent them from buckling.
Also they protect RCC structure from collapsing during seismic activity like earthquake. It is used to resist lateral shear stress and diagonal tension stress in RCC structure and provide stability to the reinforcement of Steel bar.let us discuss about how to calculate cutting length of diamond stirrups.
How to calculate cutting length of diamond stirrups
It is total length of rhombus shape closed ring having hook at one end reinforcement used in column. suppose we have given following
Size of column = 400×300 mm
Length =400 mm
Width =300 mm
Clear cover = 25 mm
Dia of stirrups=8mm
Dia of steel in column=12 mm
When we use 10 mm and 12 mm die of Steel bar in column we have clear cover is equal to 25 mm and when we use more than 12 mm die of Steel bar in column we have clear cover is equal to 40 mm.
Cutting length = perimeter of stirrup + hook length – bend elongation
first we calculate perimeter of diamond stirrups
We have given length of column
First we calculate length of a side that is base of diamond stirrups
Length of a = 400_2cover_2×4(half dia of stirrups at both sides)
Length of a = 400_2×25_2×4 mm
Length of a = 342 mm
For calculating the value of b sides we have to calculate height of diamond stirrup
We have given width= 300 mm
b sides =300_2cover_2×4(half dia of stirrups at both sides)
b side = 300_2×25_2×4 mm
b side =242 mm
Now we have a= 342 mm and b= 242 mm
Now calculate value of C by Pythagorus theorem in which C is hypotonuse a/2 is base and b/2 is perpendicular
a/2 = 342/2 =171 mm
b /2 =242/2= 121 mm
C = √ (a/2)^2+(b/2)^2
length of C =√88082
Length of C = 296.786 mm
Now perimeter = 4C
Perimeter = 4×296.786
Perimeter = 1187 mm
calculation of hook length of diamond stirrups
In rhombus shape diamond ring it has two hook length , minimum size of hook length is equal to 75 mm or 10d where d is dia of stirrup
Hook length = 10d ,but in diamond stirrups it has two hook
hook length = 2×10d
Hook length = 2×10×8=160mm
bend elongation calculation of diamond stirrups
In closed diamond stirrups reinforcement we have 3 bend at 90° and 2 bend at 135 degrees.
● bend angle 45° = 1d
● bend angle 90° = 2d
● bend angle 135°= 3d
Bend elongation =3 bend 90°+ 2 bend at 135°
Bend = 3×2d +2×3d =12d
Bend elongation = 12×8 = 96 mm
now cutting length of diamond stirrup
Cutting length = perimeter of ring + hook length – bend elongation
Cutting L = 1187+160_96 mm
Cutting length =1347 mm _96mm
Cutting length=1251 mm
Hence cutting length of diamond stirrups
Is about 1.251 meter.
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Note:- Diamond shape stirrup is Rhombus shape stirrup also known as ties bar , Diamond stirrup are very difficult to accurately fabricated and so it is avoided it is also difficult to place and align them properly.