Weld at HSS Stair Stringer Dogleg

[bookowski]

What is the appropriate weld for an HSS to HSS splice at a dogleg in a stringer? This is exterior so it needs to be closed. I was looking on a welding forum and they were howling about engineers calling out cjp because of the difficulty of getting a backing bar to fit into this layout. Stresses are well below capacity of hss so I don't need cjp for strength, just need an all around weld that is reasonably easy to achieve.

 

[KootK]

PJP? Or fillet weld both pieces to a through plate at the knuckle which is tough to make look elegant.

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.

 

[hokie66]

Never had complaints about requiring backing bars in closed sections. Some people just like to whinge.

 

[EngineeringEric]

And you just bevel one side and weld that, i am not 100% sure of the detail configuration so...? I was told by a tube distributor that they also hate CJP called out when it isn't needed, but that it can always be done.

 

[bookowski]

I can see how a backing bar is always a pain at the radius but with a dogleg it seems especially annoying. I can't see how it's easily accomplished.

For a pjp, say a single bevel groove, I guess it's a different bevel in 3 conditions - the sides, the top, and the bottom to achieve the required angle? Seems weird to me but it's probably just showing my lack of weld knowledge.

 

[KootK]

If it's not an area of aesthetic importance, I suppose that one could make the connection via fillet welded side plates and then just seal weld the rest. Might have to give some consideration to how the seal welds might end up getting stressed inadvertently in the finished product.

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.

 

[thaidavid40]

Our shop does PJP welds on rectangular tubes connecting at an angle quite frequently - and quite well. It takes some time to properly lay out the pieces, but it isn't rocket science. If the PJP welds are adequate for your purposes, then I suggest you go that route.
Dave

Thaidavid

 

[wannabeSE]

I like Hokie66's response. If I tried specifying a PJP on a stair stringer, some senior engineers in my office would whinge.