huangyhg

aisc lrfd punched holes
if you have punched holes on connection, you add the diameter by 1/8" right? where can i find that on the manual? i cant seem to find it.

it's not exactly like that. look at d3.2 of the 13th ed. spec.
no, i dont think it is in chapter d. i am doing practice questions for pe exam. i am going through this answer and i just want to know where to find it in the manual.
d3.2 in my manual, too. second paragraph.
coengineer, it's at:
d3.2, page 16.1-27 in the 13th ed.
just in case you're looking at an older manual,
b2, page 16.1-10 in the 3rd ed. lrfd
b2, page 6-34 in the 2nd ed. lrfd
lol, and while we're at it (drumroll):
b2, page 5-33 in the 1989 asd
it doesn't matter whether or not the hole is punched. it matters what limit state is being checked. for example, the extra 1/16 applies for checking shear or tension rupture, but not tear-out.
i just realized something interesting. d3.2 says that the width of a bolt hole shall be taken as 1/16 in greater than the nominal dimension of the hole. on page 16.1-105 (table j3.3) says taht the nominal dimension of the hole is 1/16" greater than the nominal size of the bolt (for a standard hole).
that being the case, the bolt hole should be taken as 1/8" greater than the nominal bolt diameter.
article 2.7 of the guide to design criteria for bolted and riveted joints reads:
"one of the critical details in a bolted or riveted structure is the fastener hole. punching the holes causes strain aging and work hardening of the material around the hole."
and
"to eliminate these points of potential crack initiation, holes should be either drilled or subpunced and then reamed in order to eliminate small surface cracks and work hardened material if brittle fracture is possible under service conditions."
under division ii of aashto's standard specifications, article 11.4.8.1 limits the thickness of material that can be punched.
so if it was punched you add 1/8? if it was drilled, you add 1/16? is that it? yeah, 271828, you are right.. i got the 3rd edition.
coengineer, no, in aisc-land, you add 1/16 to the nominal hole dimension regardless of whether it's punched or drilled. this only applies to tension rupture and shear rupture limit states, not tear-out.
for example, if you have a standard hole, when checking tension rupture, shear rupture, or block shear, you'd use the bolt diamter + 1/8.
if you have an oversided hole, you'd have the bolt diamter + 1/8 + 1/16.
oops, meant "diameter," lol. my 2 month old started crying when i typed that--and the sun was in my eyes!

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