New Steel to Existing - One Sided Connection

[bookowski]

I am connecting a new steel beam (w8) to an existing steel beam. The new beam will be accessible for connecting from one side only. The loads are small, about 5kips shear (no moment). What is the best connection to do this. Tack on a backing bar and then do a cjp of a shear tab to the existing beam? Welded single angle connection? Access is pretty tight for the work.

 

[gtaw]

How about a seat connection with a roll tab?

Best regards - Al

 

[SteelPE]

What about a single tab connection?

 

[bookowski]

gtaw - I don't think I have the room for a seated connection. The new beam is framing into an existing girder, the bottom flanges are close.

SteelPE - That's what I was thinking but what about the weld of the tab to the existing beam from one side only? I'm not too hot on my welding but I didn't think that was kosher. I was thinking that I could do a cjp of the tab to the existing beam by having them first weld in a backing bar. Access is very tight though - would prefer the simplest solution.

 

[hokie66]

Rather than welding to the existing, can you drill and use expansion anchors like Hollo-Bolts?

http://www.ancon.com.au/downloads/s3/l1/hollo-bolt.pdf

 

[msquared48]

With that small load, just se a single shear plate welded to the top and bottom flanges and web of the existing beam, with the edge of the plate extending a minimum of 3" beyond the flanges of the existing steel beam. Bolt the new beam to the plate.

Mike McCann
MMC Engineering

 

[SteelPE]

OOOHHH you only have access to one side of the connection? That's weird. I don't see why you couldn't CJP weld the connection. In fact, for skewed connections, sometimes this is unavoidable. One thing I would be worried about with this type of connection, what happens then everything doesn't exactly fit? Normally the erector would just weld the connection. That may not be possible in this scenario.

 

[dik]

Can you not just weld a plate to the web of the existing beam and bolt the new beam to it.

Dik

 

[connectegr]

How about a single angle. Weld the outstanding leg with a fillet weld along the vertical edge and a return only at the top. The other leg can be shop or field weld to the beam web.

http://www.FerrellEngineering.com

Providing fabrication and erection efficient structural design of connections. Consulting services for structural welding and bolting.

 

[bookowski]

Was originally thinking the single angle option - but I don't know if they will be able to get returns on the weld.

Rough sketch attached. The existing girder is encased in concrete, the new beam will frame such that the bottom flanges are close to the same height. There is no access from the back side in this view.

I think I'll just ask for cjp and ask the steel guy when the time comes if he has a better idea. I thought maybe I was missing something obvious but it doesn't sound like it.

 

[dik]

Good sketch... you can grind a portion of the heel of the angle to provide a prepared groove weld if you like or if you're concerned about eccentricity... else just a fillet weld along the side attached to the beam, using the other leg as a means of providing a right angle to the connection.

Dik

 

[BAretired]

Is that a plate or an angle projecting out from the existing beam? I would prefer an angle welded to the existing beam and bolted to the new beam. I am assuming you have access to both sides of the new beam.

BA

 

[hokie66]

He did say he only has access to one side of the new beam. Even with concrete on the back side, I still prefer drilling the existing beam. Two expansion or epoxy anchors should do it.

 

[connectegr]

I think they can make the return for a welded single angle. Another option is a single plate with partial penetration weld. For example use 1/2" plate with 3/8 prep (S) and 1/4 effective weld (E). Obviously you must verify that this is adequate for the end reaction.

http://www.FerrellEngineering.com

Providing fabrication and erection efficient structural design of connections. Consulting services for structural welding and bolting.

 

[azcats]

I have an oddball thought. Single angle, but strip the leg, or part of the leg of the angle against the existing beam. But leave the leg in place at the top and bottom where you can get a return weld.

So if it's a L3 that's 7" long, you remove a 4" x 2" coupon against the new beam and fillet all along that inside edge.