huangyhg

bolting through hss's
does anyone know if aisc has any specific rules about using a through bolt in a hss member? i've seen it done in aluminum tubes and you can actually crush the tube if you tighten the bolts too much.
i haven't seen a structural bolted connection made through a hss yet. almost all of the ones i've inspected have a temporary bolted connection for erection until welding to the gusset (and a couple of other temporary applications involving angle irons). haven't thought about before, but i can't recall any detail for structural bolted connections where the gap between the nut and bolt head was anything but steel.
section 7-13 of the aisc 13 edition allows for this type of connection. the main thing that you need to watch out for is over tightening (you can collapse the tube walls). this type of connection is only allowed for a shear type connection where the bolt does not need to be fully tensioned.
don't know about your code provisions, but in australia we use a lot of these type connections. for all but the tiniest loads, we specify sleeves through the hollow section.
hokie66, how do you weld the sleeves into the hss? i'm working on a similar detail and i am going to specify a partial penetration groove weld around the periphery of the sleeve. but this weld will have to be ground flush so the adjoining piece will bolt flat against the face of the hss. is that what you are doing?
thanks,
bob
bob,
yes, that is what we do. the sleeve is there to allow the bolts to be tightened. for large shear loads, it is sometimes necessary to add a doubler plate on the face of the hss to distribute the force, but then the two
thanks for all the replies. i decided to go with field welding and using a few temporary bolts to locate braces correctly.
the sleeve idea seems like it would be really labor intensive. do you do this because you can't weld in the field or have you actually found it to be cheaper than welding?
where i am, we try to avoid field welding all together if possible. both for economy and quality, our best results are obtained in the shop.
dozer,
we have specified the same sleeves in new york state.
we do this partially for strength and partially for durability as water can get inside the tubes when there is no sleeve.
the only problem is that it is difficult to allow tolerance in this connection.
csd
zipit hokie,
cwis don't need that kind of talk. we've got mouths to feed. welders do good work. only 1 out every 10 field welds i fail is for bad quality. the other 9 aren't there to judge.

dsg
you can use blind bolts also.

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