Is this weld possible? 4

[Tinguindin]

Hey Guys;

I have 61" circular plate that I will be adding stiffeners which are 5/8" thick x 12" and they vary in depth. See attached sketch.

I am the structural checking the calcs, which are fine, but is this constructable?

The spacing between the stiffeners are less than 4", and you would have to go 12" deep, can you get the gun in there at the correct angle?

Thanks

 

[DVWE]

Do your stiffening plates have to be so tall and thin? Why not a shorter, thicker plate?

If not, you could cut through holes in the circular plate and place the stiffeners through them, and weld from the other side, either a slot weld if the stiffener cannot project through, or a fillet weld if they can.

You will not be able to get a good weld as per your sketch.

 

[metengr]

Tinguindin;
Revise your plate/stiffener design. Having this many stiffeners results in poor constructability.

 

[Tinguindin]

I am the engineering reviewing this design, although the calculations seemed right, I was iffy about the constructability.

Thank you for the response.

 

[stanweld]

What is the circular plate thickness? If thin, can you stand the resultant out of flatness on the opposite side? Your design can be welded though. It is assumed that you intend to fillet weld the stiffeners to the plate.

 

[Tinguindin]

The Circular plate thickness is 5/8"

I do not see a problem standing the resultant out of flatness on the other side.

Thanks

 

[GRoberts]

While there are easier to build designs, I have seen stiffeners with more severe height to width ratios build. 4" should be enough to get a decent weld in. I've done 4" tall stiffeners with a 2" gap. This should be easier than that.

 

[Tinguindin]

GRoberts;

The stiffeners are 12" high with a 4" gap.

Regards

 

[hokie66]

I would look at doing all the welds from the same side as you go. That way, you would need backing bars for complete penetration welds, rather than trying to do fillet welds both sides in a restricted area. You are wise to consider the poor fellow who has to build this.

 

[metengr]

Tinguindin;
Increase the thickness of the plate and re-design the width of the stiffeners to reduce the number needed. This should not be that difficult to do.

 

[rmw]

Make the guy who designed it go out into the shop and build it. Then watch his next design.

rmw

 

[dik]

Yes it is possible to fabricate, albeit, not easy. You might want to suggest thicker plates and fewer stiffeners as noted above. To provide stability to the outside edges of the 12" plates, I'd likely add a bar or two tying the plates together and to the outside of the 'pipe?'. To develop the shear, a complete penetration weld is not likely needed a simple fillet weld should suffice and it may be that intermittent welds would be OK.

Dik

 

[AHaddad1]

The Load Path in your detail is not clear to give a definite answer on whether you can reduce the amount of stiffeners or not. definitely a thicker round plate would help reducing the stiffener; However, there could be other issues with reducing the number of stiffeners, like the wall of the pipe where the stiffeners are welded might not be thick enough.

It is very difficult to give a clear cut answer on your situation. Disregarding all other possible issues, the stiffeners can be welded as long as the hand can reach the height of the stiffeners. Someone has to be standing inside the pipe while welding which is not too healthy (it seems there is no end to your pipe above the round plate and stiffeners.

I would not recommend one sided welds due to weld shrinkage without a proper cooling rate that would cause weld shrinkage and therefore tilted stiffeners especially if this is done in the field and not in the shop, stay with two sided filet welds for a balanced weld shrinkage stress.

I also do not like the fact that you are trying to fit a round cut plate inside a pipe and then welding it on both sides (another accessibily issue from the other side inside the pipe). If possible, try to cut the pipe, install a very thick cap plate without stiffeners and then weld the other pipe section to the protruding cap plate from outside the pipe.

Hope this helps

 

[AHaddad1]

I like to add on this:

I stated:

Quote
If possible, try to cut the pipe, install a very thick cap plate without stiffeners and then weld the other pipe section to the protruding cap plate from outside the pipe.
Unquote

If the cap plate becomes too thick due to the 5 foot span, (like thicker than 4 inches), then you can add a single gusset stiffener plate in the center of the pipe against the 62 inch diameter cut plate, the gusset plate will also be 62 inches wide and will be fished between the pipe wall slots on both sides of the pipe. All pipe welding for the cap plate and the stiffener gusset weld will then be filet welds from outside of the pipe. The pipe weld to the cap plate can be partial penetration with enough root face to eleminate the backer rod requirement.

 

[ornerynorsk]

What's your application, this looks like a perfect job for a foundry that specializes in thin section steel, such as manhole covers.

 

[dik]

Is it possible to design it as a membrane?

 

[Tinguindin]

Thanks for the help guys. I spoke to the designer and told him to speak to welder and see the issues with good constructability.

Learned a lot, thanks

Tinguindin.