Detailing requirements for tongue plate notches in tube to gusset plate connection 2

[user277418]

Hello colleges

I have quite a basic connection like that below. I haven't made steel quite a lot of time, hence forget some special detailing requirements.

I remember in some cases I used an elongated notch for the tongue plate, but I don't remember exactly what for. My memory gives a clue that this was because of some big concentration of stresses near the end of the notch, hence the gap is to avoid the concentration. Am I right?

Also are there should be a 0.5-1mm gap between the tongue plate and the tube?

Best regards

 

[RPMG]

Extending the slot is for field erection, but AISC recommends that the slot end still be rounded with no return welds. If a clean finish is required, the end should be connected with a T-connector.

1/16" or 1.5mm gap per AISC

 

[user277418]

Thx for the reply

...but AISC recommends...

To what AISC document are you refering?

...with a T-connector.

Do you mean like a weld or a perpendicular plate on a butt edge of the tongue plate?

 

[JLNJ]

16 bolts is beyond what I'd call a "basic" connection. 200+ kips...the net section at that first row of bolts is doing work!

 

[cliff234]

"...the net section at that first row of bolts is doing work!"

JLNJ - I disagree with your statement that the first row of bolts is doing all of the work. For the configuration shown, all 16 bolts transfer the load between the plates, and each of the bolts will have about the same shear. Among the other checks you need to check block shear rupture. (Equation J4-5 in both AISC 360-10 and AISC 360-16.)

 

[user277418]

Thx for the replies guys

This is preliminary joint. I am going to check it in Idea Connections, hence don't worry. After the check the joint may change a lot. Also the bolts are prestressed, hence they should transfer loads +- uniformly.

 

[human909]

I would suggest the truth is closer to being between those extremes. Particularly in the case of tension. With bolts placed horizontally with spacing that closely then the perforation tear out along the first row would be almost certainly the limiting factor.

Without doing ANY calculations, 4 rows deep seems excessive to me given the thickness of the plate and its eccentricity. Gut feel, happy to be proven wrong.

This is preliminary joint. I am going to check it in Idea Connections, hence don't worry. After the check the joint may change a lot. Also the bolts are prestressed, hence they should transfer loads +- uniformly.

I sound like a broken record on this topic but check the connection eccentricity. If you need that many bolts then the plate doesn't look strong enough.

 

[JLNJ]

@ciff234 - I didn't mean to imply that the BOLTS were doing work, I meant that the net section of the PLATE at the first row of bolts is doing serious work - similar to what human909 points out.

I was trying to subtly encourage the OP to examine his plate size and connection geometry without explicitly stating it.

 

[human909]

Fair point JLNJ. In fact FEWER columns of bolts would likely INCREASE the connection capacity due to the reason highlighted. 3 Bolts across rather than 4 would give a greater net section.