Slip Critical Connection

[chriskrol]

Can you specify SC connection if the bolts are subjected to tension? For example hanger connection?
Thanks

 

[Lion06]

Sure, but there's really no need unless they are also subject to shear.

 

[nutte]

Yes. There is a separate equation in the AISC specification to check for slip critical bolts with applied tension.

Are the bolts only under tension, as in there is no shear on them? If so, why would you call out a slip critical connection?

 

[chriskrol]

The bolts under both tension and shear. I gave a hanger example to make it clear. What I am trying to calculate is the slip capacity of a bolt with subjected to tension.

 

[chriskrol]

Nutte,

Can you tell me where I can find this equation?
Thanks

 

[JLNJ]

Eq. 5.2 in the RCSC Spec. It's in my AISC 13th edition on page 16.2-32.

Certain types of connections usually should be SC - such as bolts in direct tension. I think it was worded directly as such in the 9th edition but the 13th seems to have an overflow of commentary, essentially leaving it up to the EOR whether to pretension or not.

 

[chriskrol]

If I understand correctly my slip capacity of the bolt is not effected by external tensile force?
Is that right?

 

[nutte]

That is not correct. Look in the 13th edition page 16.1-110, or 3rd LRFD page 16.1-66, or 9th ASD page 5-74. Any applied tension will reduce the slip resistance of a slip critical connection.

If the bolt is A325, you're not required to pretension it, although it is probably a good idea to. However, there is a difference between pretensioning a bolt and a slip critical connection. Calling for a SC connection requires surface preparation in addition to the pretension. If you just want a fully torqued bolt, call it out that way.

 

[chriskrol]

Thank you all,

 

[henri2]

Also check Table 4.1 on page 16.2-23 of the 13th edition