How would I span a dance floor roof, flat concrete roof without using support columns, just load bearing walls. the room size is 104'X70'. I thought of using steel i beams in the longest lenght 104' then using 2x10 wood joists to connect to i beams. or use steel web joists. If I use steel web joists what spacing do I use?
Even 70 feet is a loonngg span. Investigate using the style of bar joists with bolts welded to the top chord which get encased in the concrete roof deck when it is poured. I think these are called bulbs, but I might be wrong.