Cantilevered bolted angle connection design

[struct_eeyore]

Hello all,

Can someone point me to a manual or any other design aids for analysis of bolted angle connections. In my case, I am bolting a steel angle directly to a CMU wall - the angle will be oriented horizontal leg up, which will the act as a cantilever to support ~2 kip load (which comes from a 3" wide steel stair stringer that will bear on top of it). I have previously seen engineers completely discount any tension load created by the moment, and design the bolts as being purely in shear - naturally I am wondering how safe this is... Also, I imagine there is prying action, and if so, how should it be taken into account. Thanks!

 

[KootK]

- there is little prying action with the vertical leg turned upwards which is one of the reasons that we do that.

- in general, the tension on the anchor should not be ignored as a combined load is usually what governs.

- there are situations in which the angle can be considered a flexural extension of the stringers in which case it may indeed be appropriate to consider shear only. We'd need to understand the details of the connection in order to ascertain that though.


I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.

 

[dik]

Can you provide a sketch?

Dik

 

[struct_eeyore]

for a sketch -

https://imgur.com/a/i646r

. The stringer is a 12x3 HSS - will be welded to angle post erection.

 

[sandman21]

You should consider it, likely not an issue, examples can be found in "Design of Welded Structures" Omer Blodgett, PCI Handbook 7th Ed., AISC design examples V14

 

[dik]

Is the stringer prevented from rotation?

Dik

 

[KootK]

At the proportions that you've sketched, and with the vertical leg down, you may indeed have some serious prying effects. Again though, it depends on where there is restraint in the system. Under the right conditions, one could treat the vertical angle leg as essentially an extension of the vertical wall of the HSS. In that case, a pure shear design might be justified.

I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.

 

[OldBldgGuy]

I dunno, with that stringer welded to that angle, I think shear is all you're looking at...

If they are welded together so that the angle really is just an extension of the the vertical wall of the HSS as KK says.

 

[dik]

That's why I was wondering if rotation was prevented...

Dik

 

[struct_eeyore]

yes, the stringer is running against a wall, and will also be secured each end to prevent rotation.