Question { Construction, 19971 }

How to calculate stirrups cutting length in columns

Answer

1) let cover for column be 40mm (as u have not mentioned)
formula to determine cutting length of stirrup is given below
cutting length= (2A+2B)+(24D)
A=LONGER LENGTH OF COLUMN-2XCOVER=400-40X2=320MM
B=SHORTER LENGTH OF COLUMN-2XCOVER=250-40X2=170MM
D= DIAMETER OF STIRRUP BAR IN MM
therefore 
cutting length=2X320+2X170 + 24X8 =1172MM=1.172 meter
2) given cover 25mm (as u have mentioned)
formula to determine cutting length of stirrup is given below
cutting length= (2A+2B)+(24D)
A=LONGER LENGTH OF BEAM-2XCOVER=400-25X2=350MM
B=SHORTER LENGTH OF BEAM-2XCOVER=200-25X2=150MM
D= DIAMETER OF STIRRUP BAR IN MM
therefore 
cutting length=2X350+2X150 + 24X8 =1192MM=1.192 meter




NOTE SLAB COVER HAS NOTHING TO DO WITH CAL.OF STIRRUPS
3) ASSUME cover 30mm (as u have NOT mentioned)
formula to determine cutting length of stirrup is given below
cutting length= (2A+2B)+(24D)
A=LONGER LENGTH OF COLUMN/2 -COVER=400/2-30=170MM
B=SHORTER LENGTH OF COLUMN-2XCOVER=250-30X2=190MM
D= DIAMETER OF STIRRUP BAR IN MM
therefore 
cutting length=2X170+2X190 + 24X8 =912MM=0.912 meter EACH

Generally term stirrups are used for lateral tie for beams while term ring is used for columns.calculation of length for stirrups & ring are same. Stirrups length depend upon size of column/beam,cover,dia of stirrup's bar.Nominal cover is measured from outer face of stirrups to concrete face.Although this cover at site is measured from outer face of main bar.If cover for beam is 25 mm then, for 90 degree hook for 600x400 mm column & 10 mm dia bar as per IS Code 2502 length will be=2[(600-2x25)+(400-2x25)]+20x10mm=2000... 
If there are four bar of 20mm dia on 600 mm face then for central stirrup of this side will be=[600-25-25-(20/2)-(20/2)]/3=176.66 between centre of two bars of this face,now add (20/2)+(20/2) so that outer face to outer face of 20 dia bar=196.6say 197mm. same way other side of central stirrups are calculated & then add 20 times bar dia.Add 24 xdia of bar for 135 degree hook 
In IS code formula=2(A+B)+20 x bar dia. A & B are internal distance between stirrup side.