huangyhg

asd - 6 kips lrfd - 10 kips for stair
dear sir / madam,
could you provide any comments about minimum strength of connections according to:
- asd - it should be proportioned to 6 kips and
- lrfd - it should be proportioned to 10 kips.
how to use these norms for stairs calculations and especially for:
1. tread's connections to stringers and
2. post rail's to stringer and
3. stringers to stringers?
these norms are absent in asce 7-98 minimum design loads for buildings and other structures.
sincerely,


this is an outdated requirement that is no longer in the aisc specification. it was intended to provide some arbitrary minimum capacity, but the ramification was it caused miscellaneous connections, like those you mention, to be designed for much more capacity than necessary. i would disregard it, especially for your application.
dear nutte,
thank you for answer!
the same time, please, take a look on the comentary for 13-th edition of aisc manual. they are plaeing a game - for next edition they will put it up site doun.
let me ask you about max. spacing for bolts. some fabricators makes bolted tread connections to the stringers(mcnicholos co. provides treads with bolt specing c/c 7")
for example we use for stringers mc12x10.6 (thk. of web 3/16"). in that case max. spacing will be 3/16" x 24 = 4.5".
what should i do - to follow aisc standard and to take stringer with thicker web or to discegard standard?
sincerely,

you need to read the rest of the sentence: "a) for painted members or unpainted
i would disagree with that. it doesn't say the maximum of the two. if your spacing exceeds 24 times the thickness, you have violated this provision.
maybe the answer is the aisc specification deals with structural steel, and this application, stairs and treads, is not "structural steel," so this requirement does not apply.
in formal english, the difference between "and" and "or" is specifically applicable to this sentence. the "or" used means either limit can be used. if "and" was inserted for the "or", then both limits on maximum spacing must be applied at the same time.
the spacing shall not exceed 4.5" or 12".
i'm pretty good at grammar, and i know what "and" and "or" mean. i still maintain that you can't exceed either of those two.
imagine if your wife said, "you can paint the house, but you can't paint it green or red." surely you'd expect to be in trouble if you painted it one of those colors.
sorry civilperson, nutte is right.

dear sir/ madam,
please, confirm:
1. the spacing shall not exceed 4.5" for web's thk. 3/16" (mc12x10.6)
or
2. we should take stringer with thicker web.
sincerely,

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