# STAAD Foundation - Steel Density

Hi,

How does SFA determine the mass of reinforcement steel? Where can I find the steel density value/s that SFA uses?

• Please let me know the type of footing and the design code in which this MTO is generated? Also please attach the SFA file

• Assuming you have used the ACI metric code, here is my answer.

Weight of steel= Cross section area of single bar*total length*density of steel

An example calculation for the first row values in your screenshot will be

Weight in kg=( pi*(9.525/1000)^2/4 )* 145.60*7850=81.442 kg

• 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.