Couple Moment in Base Plate Bolts

[Jhinnie2]

Hi,

I have a base plate with an 75x6 Equal Angle EA bolted to a 150 PFC flange. See sketch for calculations and overall geometry. I checked the moment in the direction where bolts are eccentric and there's a tens-comp resolved by bolts(Case 2) but wondering how do I check the moment for Case 1 - is there any moment in the base plate or is it carried by the equal angle via compression and uplift of base plate and both bolts working in tension?

Thanks

 

[Ingenuity]

It is tough to read your notes/calcs even when I enlarge it to 400% - maybe it is my eyes! Maybe post as an attachment too.

For CASE 1, you may mobilize both bolts in tension to each base plate BUT the base plate connection to the 150 channel will be bending the (flexible?) web of the channel, unless there is some horizontal member that resists this action.

 

[Jhinnie2]

Hopefully this is a bit clearer? There is no horizontal member that resists the bending of the web, I think this 150PFC is just a small floor trimmer quite close to a column support - see photo attached (note EA toes drawn wrong orientation). I haven't done a 2-bolt moment connection like this but it seems common for all the handrail base plates.

Link
Link
[link img

https://res.cloudinary.com/engineering-com/image/upload/v1633037119/tips/image003_tru1lu.jpg

]Link[/url]

 

[Enhineyero]

Case 1 moment is carried by EA then transferred to the PFC by bolt tension/base plate compression, I think you have that.

Couple of things that I didn't see here but would recommend to be carried out.
1. Check bolt/base plate for prying forces.
2. Check PFC flange against bending failure (due to bolt tension), you may likely need a full depth cleat connecting top and bottom flange to limit flange bending (or at least mobilise the whole section).
3. If PFC is not restrained effectively by a floor type structure or to another beam then I would check it for torsion