I am creating a storage. The trusses are getting shipped tomorrow. When I purchased them, I did not understand that I needed to set up a attic. I wish to understand whether the trusses could be strengthened to maintain that sort of weight?
First, what kind of storage, ie. how much weight spread over what area?
The easiest thing to do is ask your truss supplier. They can tell you exactly what the bottom chords can support. I'd say that that design load wouldn't be a figure too much higher than the dead load imposed by the "warm" side ceiling covering, eg. drywall/sheetrock and the "cold" side insulation.
Unless someone specifically asks for attic trusses meant to carry a 2nd floor/attic storage, truss manufacturers don't just make them extra strong for potentials. They have to bid them for the purpose intended or they would never have their quotes accepted.