Applies To
	Product(s):	STAAD Advanced Concrete Design
	Version(s):	All
	Environment:	N/A
	Area:	Concrete Design
	Subarea:	IS 456:2000
	Original Author:	Abhisek Mandal Bentley Technical Support Group

I am unable to match the shear reinforcement for the beam designed as per IS456:2000. For manual calculation I am getting 8mm dia bar at 250 C/C. But Output is showing less spacing. Size of beam is 300x600mm and clear cover is 65mm.

In most of the cases we ignore the torsion criteria when calculating the minimum spacing of stirrups ina  beam. We need to include the clause of transverse reinforcement 25.5.1.7a) of IS 456:2000,  if torsion is present. This check is additional to the reinforcement requirement due to unbalanced shear in the beam. Even if a very little amount of torsion is present in the beam that may not affect the shear force value much, the above mentioned clause gets triggered and the reinforcement spacing criteria checked with that requirement. 

For the above example as per the clause,

X1 = 300 - 2*65 +8 = 178mm.

Y1 = 600 - 2*65 +8 = 478mm.

(X1 + Y1) / 4 = (178+478)/ 4 =164mm.

Hence required minimum spacing is 164mm.