Slab Edge Angle Under Torsion?

[SteelPE]

I have a condition where we have a post installed angle at the corner of a suspended concrete slab. The angle will be subjected to a torsion load with post installed angles to transfer these loads into the slab (not a great condition, but I have no control over the condition). In the attached sketch you will see two loading conditions. I am pretty convinced that case #2 is correct for negative torsion, however I am not fully convinced that case #1 is correct for positive torsion. My other option for Case #1 is to put a tension load in bolt #1 which would then require a shear load in bolt #2, but I am not convinced that this is correct either. How would others handle this situation?

 

[dik]

Unless the moment can act in both directions, Bolt#2 does little and may interfere with forces on Bolt#1. Is it a significant moment? and can it be handled as flexure and not torsion?

Dik

 

[SteelPE]

dik,

The moment isn't overly large (2,100 in-lbs/ft) and can act in both directions. This is a support for a glass railing shoe. I'm not worried about the angle but rather the post installed anchors which are not really good at the edge distances proposed.

 

[kipfoot]

My other option for Case #1 is to put a tension load in bolt #1 which would then require a shear load in bolt #2,

Another thought for Case #1: tension load in bolt #1 and a compression zone at the top surface of the slab. I think that pressure on the slab would engage before shear at bolt #2. This means you'd have a shorter moment arm for the couple in Case #1.

It's not part of your question, but in Case #1 I also see a horizontal reaction on the bolts in addition to the moment.

 

[Teguci]

Don't forget the 50 lbs/ft lateral load as well.

I think solving for the loads as you have shown in your sketch is appropriate.