correct and best welding on a gusset plate

[lolobau]

Hi guys

in our office we have a debate about the best welding of the angle section on a gusset plate.
See attached image. I have my own theory and my colleagues also they own one. Now I wanted to extend the debate on this forum to get maybe some new ideas.

Where and how would you weld the angle section on the gusset plate?

Lolobau

 

[DETstru]

I usually weld the entirety of the blue edge and whatever distance I need on the red and green edges starting from where they intersect the blue edge.

 

[lolobau]

see image

 

[BMart006]

Welding so that the red and green lines are equal in length will result in an eccentricity being induced in the angle. If you intend for the load to go through the shear center (or at least near it), you need to balance your weld lengths so that the weld group CG corresponds to the line of action. See commentary section J1.7 in AISC 14th for an illustration.

 

[KootK]

I'm still a sucker for the "balanced" welding with the red weld doing the lion's share of the work. I believe that method has fallen out of vogue however as some combination of experience and testing has led to the conclusion that it's not a big deal. Sometimes I'll size the red weld for balance and then use the same weld length at the green weld to keep things simple. I generally design angles assuming that they're eccentrically loaded anyhow.

I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.

 

[gravityandinertia]

I know there exist information about balancing the weld, however, when I worked for a joist manufacturer, we always did a full weld along any overlapping edges. The only check was that we had enough overlap to cover our minimum for our design loads. Right or wrong due to eccentricities that could be introduced, that's how they had always done it, and didn't have joist failing, so they assumed it was fine.

Realistically, in the shop/place of fabrication no one is going to want to measure the specified weld amount for each joist, if they just know, weld anywhere weld will fit, things go faster and less chance of mixing up different structural members and how much weld they require from drawings.

 

[P1ENG]

I know there is talk of eccentric loading on the weld, but the process and some detailing requirements are shown in the commentary of the AISC SCM:

Juston Fluckey, SE, PE, AWS CWI
Engineering Consultant

 

[P1ENG]

You can adjust the weld strength by the shear lag factor of Chapter D of AISC 360:

Juston Fluckey, SE, PE, AWS CWI
Engineering Consultant

 

[racookpe1978]

With today's quality of welders and (lack of) training and supervision, it is more prudent to weld all-around the three colored lengths rather than expect the welder (and his/her lack of years of experience) to properly adjust each of the three sides for each different joint, angle iron width and gusset plate size every time.