AS3600 development of stresses around a bend
AS3600 development of stresses around a bend
(OP)
In AS3600, there is s clause which stipulates that in order to enable stress development around the curve of a reinforcing bar, the internal diameter of the curve must be greater than 10 x the diameter of the bar. Does anyone know where this come from ? I suspect this is something to do with bearing stress of the steel acting on the concrete at the bend. Is a 10 d_b curve sufficient to prevent bearing failure when the bar is fully stressed in tension ?






RE: AS3600 development of stresses around a bend
I have made a small all bonded steel and concrete model to see the stresses and results that the tensile stresses are worst where spall would be expected on the bent bar. On the other hand crushing stresses at the curve remain well within the capacity of the concrete.
It is also worth to mention how full bond -as in the model- resolves the force to manageable tensile stresses in the concrete in a very short length of bar.
RE: AS3600 development of stresses around a bend
Yes, that is the logic! I assume it is based on tests.
If you can get a copy of the British Code, BS8110, clause 3.12.8.23-25 gives more detailed rules on this including calculations for the bearing stress in bends and allowable values.