Why is the cutting length for a shape code 86 calculated in Padds different from cutting length calculated with the formula in SANS 282:2011?
In the SABS 82:1978 detailing code the formula for shape code 86 is:
L=C/B*π*(A-d) + 8d
This does not take into account the height effect of B. In the later versions of the detailing code the height effect of B is incorporated, but this is done incorrectly.
If you take the spiral of one segment and make it straight, the vertical component has a value of B and the horizontal component has a value of:
Using Pythagoras the diagonal has a value of:
The equivalent value from the new detailing code is:
Padds and AutoPadds modifies the formula from the SABS 82:1978 detailing code to incorporate the height effect of B and this resulted in the following formula: