How does SFA determine the mass of reinforcement steel? Where can I find the steel density value/s that SFA uses?
SFA calculates bar number and number of bars during reinforcement calculation. For example #8 @ 250 mm c/c means #8 bar is used at 250 mm c/c spacing.
Now we know the bar area for #8. And we can calculate the number of bars as 1+ roundup( (Total span - 2x cover - bar dia)/ spacing).
Next, we know the dimension of the footing in reverse direction, SO each bar length = Dimension of footing at that direction - 2x cover
So, if we have bar area bar length, we can calculate bar volume. Now density of steel is 7850 kg/***. So, SFA follows the procedure to calculate weight.