How Short is Too Short for a Steel Joist of a Particular Depth
How Short is Too Short for a Steel Joist of a Particular Depth
(OP)
Just like the title says. Say I have a 16" joist. How short of a span could I go to before it's not feasible to produce such a thing? Additional info:
- Yeah, I'll call somebody if I don't get what I need here.
- Not concerned with economy. It's a client/mech decision.
- Tables seem to stop around h x 12 but I've certainly gotten shorter than that in the past.
- Yeah, I'll call somebody if I don't get what I need here.
- Not concerned with economy. It's a client/mech decision.
- Tables seem to stop around h x 12 but I've certainly gotten shorter than that in the past.
I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.






RE: How Short is Too Short for a Steel Joist of a Particular Depth
RE: How Short is Too Short for a Steel Joist of a Particular Depth
RE: How Short is Too Short for a Steel Joist of a Particular Depth
Joist depth/Minimum Base Length
10"/5'-2" 12"/5'-6" 14"/5'-10" 16"/7'-0" 18" rod/7'-4" 18" crimp/9'-4"
20" rod/7'-8" 20" crimp/9'-10" 22"/10'-6" 24"/11'-0" 26"/11'-0"
28"/11'-6" 30"/12'-0"
Those are only Vulcrafts numbers and it's 10 years old so take it with a grain of salt.
RE: How Short is Too Short for a Steel Joist of a Particular Depth
Dik
RE: How Short is Too Short for a Steel Joist of a Particular Depth
This would be dumb. I bet someone would make it, though, if you really pushed.
More realistically, I think that it's probably twice the end panel length plus one standard interior panel. That'd be \/\/. So ballparking, it'd be somewhere in the 4*Depth range, maybe lower with a more aggressive web angle.
RE: How Short is Too Short for a Steel Joist of a Particular Depth
You probably need at least one panel point at mid-length of the top chord or the top chord member would almost make the span, by itself, as a simple beam. Then, you need the two end diags. from the bot. chord up to the end bearings, plus the end bearing lengths. Then, the issue becomes how tightly you can bend the diag. bar stock without cracking it, and still be able to get enough welding in place. In the end you are moving from a truss with triangular diags., almost to a vierendeel truss.
RE: How Short is Too Short for a Steel Joist of a Particular Depth
Is my thinking off here? Am I missing something?
RE: How Short is Too Short for a Steel Joist of a Particular Depth
joist depth/ panel size
10"/1'-7" 12"/1'-7" 14"/1'-7" 16"/2'-0" 18" Rod/2'-0" 18" Crimp/4'-0" 20" Rod/2'-0" 20" Crimp/4'-0"
All of the remainder of the depths to 30" had a panel size of 4'-0"
RE: How Short is Too Short for a Steel Joist of a Particular Depth
I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.