Required strength of connectors for double angle compression members? 2

[abusementpark]

Anyone know what the strength requirements are for connectors of double angle compression members? The compression tables in the AISC steel manual indicate the number of connectors required along the length of the member, but don't seem to give any strength requirements, unless I am missing something.

 

[TLHS]

The Canadian steel code (CSA S16-01) specifically requires that it be designed to 1% of the axial load in the combined member.

Since 1% of the combined load is 2% of each individual angle, I've always just assumed that they basically just used the same bracing requirements as any other compression member, which is 2% in the Canadian code.

 

[structSU10]

If you go to the commentary for section E.6 in AISC 360-05

The end connection must be welded or a fully tensioned bolt...The connectors must be designed to resist the shear forces that develop in the buckled member

I would assume from this you could use the equations from appendix 6, treating the bolt as a nodal brace, designing it for 1% the compressive force.

 

[abusementpark]

How would you determine the shear forces developed in the buckled member?

Treating the bolt as nodal brace would be checking it for an axial force, not a shear force. It seems inconsistent with the AISC commentary you quoted.

 

[paddingtongreen]

It would buckle sideways about the weak axis, complimentary shear forces then appear.

Michael.
Timing has a lot to do with the outcome of a rain dance.

 

[structSU10]

What I mean is it would be modeled where the bolt would be a brace point, and shear is induced as the member begins to buckle in a certain direction, so i would assume it could be idealized as a nodal brace and design the 1% value for the shear. The only other option is a complete 2nd order analysis.

 

[WARose]

I don’t know if you have any of the old AISC Steel journals on CD (or whatever) but they had a paper in the 3rd quarter of 1992 that addressed stitch strength requirements based on buckling. [I assume it would be applicable to bolts spacing and you could superimpose the shear requirements.]

The name of the article was ‘Analytical Criteria for Stitch Strength of Built Up Compression Members’.

 

[WillisV]

http://www.modernsteel.com/Uploads/Issues/June_2010/062010_June10_si_web.pdf

First Answer. Same reference as WARose but condensed to what you need to know.

 

[abusementpark]

Thanks a lot WillisV!