Bolted Partial Moment Connection - PFC to Tube Section

[m_struct]

I am looking for any guidance on bolted beam column connection for channel to tube steel post. The moment frame supporting the front end of a deck. The tube steel posts are fixed base with a post hole foundations. For constructability the beam column joint is bolted and the design only requires partial moment connection as the lateral resistance is coming from the cantilevered posts. Refer to detail below.

 

[Tomfh]

As present it has some moment capacity.

How much strength do you need?



Note that a lot of decks don’t have any stability like this, and instead are braced back to the structure. Eg some cross bracing under the deck, or simply the decking boards and nails themselves. See this thread.

https://www.eng-tips.com/viewthread.cfm?qid=475916

 

[dik]

As long as strength and stability are looked after, I don't see any issues... might need a tapered washer for the connection, and can your stiffener plates be terminated 1" from the top flange of the channel section. For steel connections, other than stair tread supports, I don't like using anything less than 5/8" HS bolts... ie, your 15mm. Can you use an HSS 100x100? or do you need some greater moment capacity? If so, you might want to thicken the cap plate.

Rather than think climate change and the corona virus as science, think of it as the wrath of God. Feel any better?

-Dik

 

[human909]

Looks largely good. I think you'd want a thicker plate that 12mm, say 20mm to achieve something closer to a rigid connection. But like you say if you are only after a partial moment connection this seems to achieve that.

I don't see any issues... might need a tapered washer for the connection

That is why we down south use the P in parallel flanged channel. ;-)

 

[m_struct]

Thank you for the feedback.

For a more rigid connection, add a thicker plate . . . How about a second bolt on the inside connection?

Dik - That's right, 150x100 RHS is needed for the flexure strength.

 

[human909]

For a more rigid connection, add a thicker plate . . . How about a second bolt on the inside connection?

No second bolt needed. If it was my connection I'd be using 20mm bolts with a 20mm plate. (Note I haven't done any calculations here. Just gut feeling based on past designs.)

I would expect that the moment capacity of 230 PFC or a 150x100x9 would be bit higher than a single M20 in tension let alone a single M16.

 

[Tomfh]

You could also make it stiffer but adding side plates to the PFC, same length as the cap plate. Then the PFC flange can’t bend as easily.

 

[dik]

You might want to increase your cap plate size... looks a little light; have you considered prying action on the bolts... also just for stiffness. M19 bolts might be more appropriate, but I suspect for loading the M15 work. In these environs, M19 bolts are less costly than M20s.

Rather than think climate change and the corona virus as science, think of it as the wrath of God. Feel any better?

-Dik