huangyhg

designation of bolted connections...
when drawing slip critical, direct tension or other bolted connections that would require other than a snug tight condition, how are these connections designated on prints?
find a job or post a job opening
if you have a great number of these connections, maybe designate them as a dot or something simlar on plan. if it is only a few at unique, detailed locations, just show it in the detail.
i would normally put a note saying "fixed connections indicated thus..." or similar. no mis-understandings then.
csd
usually that information is indicated on the notes:
- all bolts to be tensioned as per ... unless noted otherwise
notes are ok but i would also use the standard nomenclature in the bolt call out such as "a325 sc" when calling out slip critical bolts. "x" is a bearing connection with threads excluded, "n" is a bearing connection with threads included. i guess "dt" is direct tension. i saw that on a web site but i don't re
as far as designating them on drawings, we have a general note covering the majority of bolts and then anything different is designated on the details or plans.
i prefer to use 3/4" dia. type n a325 uno. if i require sc, use tc bolts. they are easy for you, your inspector and the iron workers to check in the field. if i need larger bolts, i go two sizes larger (1") so they are not mixed up in the field.
jike,
are all tc bolts sc?
the tc (tension control) bolts have a spline on them that pops off when they are properly tensioned to the slip critical force. as you are walking around, the shiny ends indicate that they were already tensioned.
this has me thinking now. a steel fabricator use tc bolts for bearing type connections. if the slip-critical bolt is not needed, but provided, can you ignore the slip-critical values in aisc (as they are lower than the bearing connections shear values - even using slip at a serviceability limit state) and just assume you can count on the full value of an a325n when they will slip into bearing?
i guess i am thinking about this a little more and you should be able to use the bearing (a325n) values if slip is not a concern at any level correct? what if these bolts were installed without consideration given to the faying surfaces, then the whole slip-critical thing is not valid anyway and you would be right back to the simple a325n bolt values, correct?
one problem that i see with using tc bolts for connections designed as bearing (i.e. no consideration for faying surfaces, etc.), is the "banging bolts" phenomenon. however, some people at aisc said they haven't heard of that problem in years, and our office usually specifies tc bolts with or without sc connections due to ease of construction, inspection, etc.

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