FULLY BUTT WELDED BEAMS

[lmcan]

I have 2 DIFFERENT SIZE wide flange beams in a cantilever construction( beam over column) to be welded in the field.

1. Can I weld the beams along their webs ONLY(Butt weld) without going for one sided or both sided plates and still achieve the transfer of shear from one beam to other?

2. Is there any way to make it a continuous connection( moment connection) without welding plates at top/bottom or on sides?

 

[UcfSE]

If you only need shear transfer I would go with some sort of bolted arrangement, such as a double plate or double angles with bolted flanges. You can weld the web for shear only but there may be more details to work out than just saying full penetration weld at the web. Go with a single bevel weld unless the webs are less than about 1/8-inch thick in which case I'd use a square butt weld. If they are greater than about 5/8-inch to 3/4-inch you'll probably need a "V" weld. This may or may not work out depending on just how different the beams sizes are. For that reason and for simplicity in construction I recommend using bolts.

You can make a full moment connection without plates depending again on how much difference there is in the beam sizes. Assuming the difference is small, you can use a full-penetration weld, single bevel or "V", to splice the beams and provide continuity across the flanges. If the difference in size is substantial you won't be able to physically weld the flanges to provide continuity without some extra steel.

It all comes back to just how different the beams are, and how substantial the loads are. Those two variables will play a major role in whether your different solutions will not only satisfy the engineer involved but also be practical enough to be done.

 

[VirtualEngineer]

I think you pretty much have to make sure you tranfer the flange load and web load for a moment connection.

You can do this with welds, or with splice plates and bolts.

One option is to use endplates.

There are several good references for endplate moment design in the AISC design guides.

http://www.aisc.org/Template.cfm?Se...aggedPageDisplay.cfm&TPLID=21&ContentID=22619

Design guide 4 and design guide 16 are good references for endplate design.

Regards,

JPJ