Quote Originally Posted by sm95m View Post
One thing you need to bare in mind is a joist like this generally have the top chord fully braced by decking, In your case top chord buckling is limited only by how well you attached your ledger - kind of a complicated analysis. Also the bottom chord is not really meant for loading. If you check out the Steel Joist Institute web site you should find some info on loading joists.
for Sh*ts and giggles I modeled on the computer with a 50#/ft dead load and a 100#/ft live (storage) load and the 3/8" rod is overstressed as much as 145% - especially at the ends where the web members do most of the work. if you look at a manufactured bar-joist the web members are small but bigger near the supports. heaviest loaded diagonal is the last one on each end. Deflections are OK @ full 150 PLF load