Welding of SHS to I Beam End-to-End

[scotland6]

Hi Guys,

I wish to weld a 250mm SHS with an internal flush end cap to a 200HEB I beam. The combined beam will be horizontal and the bottom of the SHS will align with the bottom flange of the I beam, see attached. The connection will be subject to bending forces, not yet established. Is it practice to add some stiffening / re-enforcement to the top and or angle on either side of web to improve the connection?

Regards

John

 

[racookpe1978]

You are trying to pass the entire load - moment (bending moment down ?) AND shear - from the I-beam (WF shape ?) through its fillet welds to the flat steel end plate inside the HSS member through the (what kind of weld ?) to the inner wall of the hollow HSS member to the main webs and flanges of the HSS.

Poor idea. Instead, I'd recommend a thicker flat plate over the end of the HSS, welded all-around with a larger fillet weld to the HSS. An outside fillet over a full-penetration prep joint is easier, more reliable, larger, longer, and easier to inspect than a small inside weld tucked into the HSS. Hard to cut the inside piece accurately too without machining the corners and radii of the inserted small end plate.

Once the thicker flat plate is in place, then weld the WF/I beam to the end plate.

 

[KootK]

Frankly, I'd avoid this connection configuration unless the moment is trivial. For serious moment, I'd weld a short length of custom WT or channel to the top of the wide flange so that the top flanges of the two members do effectively align. Or make the wide flange the deeper member and throw in some horizontal stiffeners if that is feasible here.

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.

 

[dhengr]

Scotland6:
That’s a pretty mangy detail to do well in the real world, even though CAD allows you to draw it perfectly. I would like to know a lot more about the loads, moments, shears, the potential for fatigue and vibration, etc. I would like to see more of the entire machine to really see how this is going to work, how it is loaded, why it has taken that shape. And, I might look for another way. I would like to see dimensions, and accurately scaled drawings to see how things really fit together. I might even change member sizes for better fit-up, rather than just stresses. You will likely end up with a bunch of partial penetration welds, likely some questionable root penetration issues, some stress raisers and triaxial weld stress conditions.

You could rip (saw cut?) the WF web about 10-12" long, into the WF length, from the joint/the WF’s end. Do this about 2-3" below the bottom of the top flange, well below the ‘k’ area of the flg./web. Heat a spot at the end of this cut, and bend the top flg. and web up, so its free end matches the height of the HSS. Cut a stl. pl. wedge to fill the WF web space and weld it in to fill this web gap. Trim, grind, clean-up and bevel the end of the WF as needs be so you can weld the two WF flgs. to the HSS top and bot. walls, and fillet weld the WF web to your HSS end pl. Make your HSS end pl. fit the inside of the HSS well, but let it extend out beyond the end of the HSS by 3-5mm and use this extension as an effective land for welding the WF flgs. to the top and bot. HSS walls. Otherwise, prep. the end of the HSS (inside bevels all around) for welding to the end pl. and finish this with a 3mm reinforcing fillet all around.

 

[scotland6]

Hi Guys,

Please see attached picture of the frame. Its a 30ft ISO frame 8f x 8ft and it carried a large pressure vessel. I have a requirement to remove as much wight as possible hence the joint. The moment acting on the connection will be minimal but I want get the specifics right for fabrication. I have changed the end cap and added a cut channel section to take up the gap a the top of the i beam and the box. The pv, which is not shown, will carry a lot of the bending when the frame is lifted via the ISO castings which are either side of the large fabricated i beam. What is shown is replicated at the other end of the ISO frame.

Regards

John