Moment Connection using RISA Connection 1

[structure_engineer]

Hello Engineers,

I am designing an extended end plate moment connection using W12x26 framing into W10x33, W10x39 or W10x45 columns. On page 18 of the Design Guide 4 Extended End-Plate Moment connections 2nd ed., there is a requirement to use CJP (Complete Joint Penetration) weld if the flange thickness is greater than 3/8". In my case it is at 3/8" thickness exactly. Do you follow this requirement if say a 1/2" tf is used? Do you know where is this coming from? I recalled in another company I have seen this before. Now I am in a sort of different industry stream and was told to ignore this requirement by another fellow structural engineer. Regardless, I think design guide requirements needs to be followed no matter what is the nature of the industry or plant we are building. What do you think? Below is the screen capture of the partial content of page 18:

Your time and input is much appreciated.

 

[ads0221]

I’ve come across this numerous times and still haven’t figured it out. We use RAM Connection as well and this is never an issue with that program.

 

[DrZoidberWoop]

I would disregard the 3/8" CJP suggestion in DG 4 & 16, unless you have some seismic thing to account for. I can't think of a single time I've used a CJP at an end plate. It incurs additional costs in weld prep, inspection, and even a 5/16 backing fillet. A pair of single-pass 5/16" fillets will nearly develop a 1/2" gr50 flange.

A CJP for every end-plate connection could really start to cost big money if there are a lot of them on the job, especially when fillet welds would suffice. Also, by the time a moment pushes the limit of an end-plate, I consider using a flange plated moment connection instead.

You are working with really small columns. If your end-plate to column web connections are only on one side, consider the effects of yield line (AISC 15th Eq 9-31).

It will be interesting to see how they present welding in DG 39, which will supersede DG 4 & 16. SHould be out later this summer.

 

[JoshPlumSE]

Do you follow this requirement if say a 1/2" tf is used? Do you know where is this coming from?
Well, if it's a seismic connection (IMF or SMF), I would tend to follow the requirement from AISC 358. That's the legal requirement and I don't see your DG-4 requirement in 358, but I do see the following:
"... the beam web and flanges shall be connected using either a CJP groove weld or a pair of fillet welds each having a size 75% of the beam web thickness but not less than 1/4in.".

For what it's worth, this 75% thickness of the beam web requirement is from testing at Virginia Tech. I believe the testing shows that the weld at the beam / flange intersection could fracture if were not stronger than the beam web.

If you connection were an OMF... I'm not sure whether DG-4 really applies. Certainly if it's an R = 3 connection, I wouldn't worry about DG4 a all. Meaning, the more lax requirements of DG 16 are more applicable for R=3 connections.

DrZ: I didn't realize a DG39 would be coming out on this type of bolted moment connections.... Makes me realize how much I'm missing out on now that I no longer attend the AISC committee meetings.

 

[structure_engineer]

Thank you all so much for the responses.

I have the same inclination at the time of working on that connection. Recently. my colleague came up with the same specification for the moment connection on the same project. This is a high wind location so definitely no OMF, IMF or SMF. I would have to share with my colleague and ask them to ignore the CJP requirement as specified by the software. Great insight and guidance. Keep up the good work guys. This site rocks.