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AISC Style Moment Connection 4

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dik

dik

Structural
Joined
Apr 13, 2001
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I need to provide a moment connection to splice a beam. Space is limited and the entire length of beam cannot be installed in this existing building, so needs to go in 2 parts. Moment is always +ve and only need bolts on one side of the beam.

Does anyone see any contraindications for the connection (in sketch)
Conn-Moment_End_Plate__8_Bolt_owrvnn.png
I propose to design?


4 bolts at the one side doesn't do it unless I go to 1" dia and not 3/4" dia (client's preference). I also note the AISC uses a CJP or PJP weld at the flange to the end plate. Any reason this cannot be a fillet weld?

Dik
 
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Hi dik,

You can refer to AISC Design Guide 13 to design the splice. Your design model seems valid to me, but there are some options that you can take from the design guide.

End_plate_1_xtbvqg.jpg


End_plate_2_qn28b7.jpg


dik said:
I also note the AISC uses a CJP or PJP weld at the flange to the end plate. Any reason this cannot be a fillet weld?
Click to expand...

There is nothing in the AISC that prohibits the use of fillet welds for end plate connections (unless it is a high seismic design, which doesn't seem to be the case here). There are many design examples throughout the AISC design guides and manuals in which they use fillet welds for the beam flange to end plate joint.
 
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Found it in DG 16... thanks

Dik
 
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Yes, you are right, i meant DG 16, sorry for the typo.
 
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With just the two bolts near the compression flange, I wouldn't mind seeing some lateral bracing near by. These kinds of joints usually tend to occur at natural bracing locations.
 
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Agreed... but they have a clamping force of about 30K each or about 60K total for 3/4" A325s


Dik
 
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Any idea of units? Just drop the inches?

image_dumskg.png


Dik
 
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Where you get that equation from?
 
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dik said:
Any idea of units? Just drop the inches?
Click to expand...

Yes, the results are given in inches, see the design example below.

AISC_DG16_qrcbd3.jpg


Here are some interesting notes on the design of the weld between the beam flange and the end plate.

AISC_DG16-weld_pnkrou.jpg
 
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Any reason not to use web and flange splice plates?
 
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It's from DG 16...

Dik
 
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Thanks... the formula gives a minimum value to use one unitless and one in inches. SMath pukes when units don't match. When I finish the program I'll post it here for comments/others to use.



Dik
 
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Dik,

Yes, aois in inches. See DG16 p.61 "App. A Nomenclature" for explanation.
 
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Dik,

I could have missed something on DG16's equations, to me, they are not always unit consistent. So program your worksheet to restrict the unit of input field, but carry out unitless calculation in the operation to avoid your program from puking :)
 
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Easy work around... you divide the variable by the unit to make it unitless. It always raises the question if the formula is correct.

Dik
 
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I am not convinced that the yield lines shown in red actually occur. If they are removed, there is a trapezoid each side of the vertical plate which has a single slope.

image_ejmgqh.png


BA
 
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BAretired said:
I am not convinced that the yield lines shown in red actually occur. If they are removed, there is a trapezoid each side of the vertical plate which has a single slope.
Click to expand...

Due to the virtual rotation in the connection, the virtual displacements at each bolt lines are different. Therefore, those yield lines are required for compatibility and to complete the plastic mechanism. In other words, without those red yield lines there would be no kinematic mechanism.

Yield_line_mechanism_nowzwk.jpg
 
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Bart... they happen for compatibility...

Dik
 
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Yes, I see it now. Thanks PROYECTOR. Excellent explanation. I should have seen that for myself.

BA
 
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Yes, thanks Proyector. When BARetired posted his comment, I was walking along the path with him. I was 75% of the way to convincing myself that he was right before I read your post.

Note: This is why I like Eng-Tips. When someone challenges conventional thinking (even when they're incorrect) it forces us to better understand the issue and why "conventional thinking" is right or wrong.
 
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