Hi @alijalil,
I don’t understand what you are trying to achieve. Calculating the weight of a theoretical I-beam is a pointless exercise if it’s not commercially available. As far as I know the lightest commercially available I-beam is 14 kg/m. If you want a lighter member, you will need to look at alternative sections such as cold rolled C-channel or lipped C-channel.
As discussed previously, I believe these lighter sections are more appropriate for your application. However, you will need to change your design to suit. For example, you will probably need to include diagonal bracing and check for resistance to buckling.