Second floor weight limit

The size of the engineered I joists will be the determining factor. You should consult with the manufacturer for the loading limitations.

Glenn

Not only size of I-joist but the span and spacing enters the formulae. I built one recently specifically for a pool table and concluded this,
The normal engineering for living space will support the normal pool table when you conbsider that the overall space required to play pool around it is at least 168 sq ft. With three or four husky guys playing the game in that space, it works out to only a little over ten pounds per foot and normal live load design is fourty.

But I chose to design in a little more - fifty pound live load - so that there would be no agravating vibrations as people walked across the room.