Unknown Steel Joist Configuartion

[stevenspm]

Hello,
I have a project where I am evaluating a roof for a mechanical unit and have come across a steel joist, see attached picture, I have not seen before and I was wondering if any one here has seen one of these before. The joist has double angle top and bottom chords like a typical steel joist, but the webs alternate between double angles, appear to be compression elements, and round bar for the tension.
Thanks
Phil S.

 

[JedClampett]

The joist manufacturers make these up with whatever is laying around. If they have bar stock and angles, they'll use that. If they have just angles, they'll use that.
That's one of the things that makes working with these so much fun. If you can figure out who made them and call them up, they won't have any records (fire; flood; paper eating mice) and they'll just tell you "...it's adequate for the design required, good day."