Single Angle Compression Members, interpretation of AISC 360-05 Section E5b

[jochav5280]

Good afternoon:

Would someone advise if I am interpreting Section E5b of AISC 360-05 correctly?

E5b says:

For equal-leg angles or unequal-leg angles connected through the longer leg that are web members of box or space trusses with adjacent web members attached to the same side of the gusset plate or chord:

I interpret "with adjacent web members attached to the same side of the gusset plate or chord" as meaning that there must be an adjacent angle on the same gusset or chord connection location. My interpretation makes sense to me as you would need an adjacent tension angle at the same location to offset the moment induced by the compression angle about the plane of the gusset or chord. My colleague disagrees with my interpretation, insisting that this is not saying that there must be an adjacent brace connection, just that all adjacent angles must be attached to the same side of the gusset or chord.

I'd appreciate some help.

Many thanks in advance,

jochav5280

 

[KootK]

I agree with your interpretation. The commentary states that idea is for the compression member to benefit from rotational restraint of the chord at the joint provided by adjacent web members at the joint. No adjacent web member at joint = no rotational restraint for joint = no reduced K for compression member.

This section of AISC could really use a rewrite and perhaps some diagrams. It's pretty tough to decipher.

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