STEEL STAIR STRINGER DESIGN
STEEL STAIR STRINGER DESIGN
(OP)
When designing steel stair stringer, I always consider stringer compression flange unbraced, since light Gage tread will not brace the compression flange like a slab or other diaphragm. The stair manufacturer wants me to design assuming compression flange is fully braced. Any opinion?






RE: STEEL STAIR STRINGER DESIGN
But I think others here may disagree.
DaveAtkins
RE: STEEL STAIR STRINGER DESIGN
RE: STEEL STAIR STRINGER DESIGN
RE: STEEL STAIR STRINGER DESIGN
In any case the fact is that threads and their support many times (but not always) engage the stringers in such a way (threads joined to the webs, compressed flanges restrained against torsion by their union to the thread and vertical plate of the step) that the outfit becomes reasonably stout against LTB of the compressed flange, say, the upper flange.
Only when unable to restrain torsion by the general weakness of the thread your conservative assumption will be the required one. There's a way out of this and is modeling the stair with all details, even providing initial imperfections, with P-Delta and P-delta, then (segment) member analysis by formulas in the code(s), and you will know if you are safe against this in whatever the case.
RE: STEEL STAIR STRINGER DESIGN
http://www.FerrellEngineering.com
RE: STEEL STAIR STRINGER DESIGN
RE: STEEL STAIR STRINGER DESIGN
RE: STEEL STAIR STRINGER DESIGN
RE: STEEL STAIR STRINGER DESIGN
See manual at:
https
RE: STEEL STAIR STRINGER DESIGN
1. Top(Compression) & Bottom(Tension) flanges is supported.
2. Weak Axis - Braced at the length between treads.
3. Strong Axis - Unbraced. The stringer is free to flex over the full length.
RE: STEEL STAIR STRINGER DESIGN
I treat my stringers as fully restrained.
The proof of this is that I have designed many vertical plate stringers on this basis and never had one failing.
RE: STEEL STAIR STRINGER DESIGN
The stringers are fully braced.
RE: STEEL STAIR STRINGER DESIGN
These were with bolted grating treads.
Michael.
Timing has a lot to do with the outcome of a rain dance.