×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!
  • Students Click Here

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

Jobs

Welded Splice

Welded Splice

Welded Splice

(OP)
I need to design a welded splice at beam to beam connection only taking gravity loads (cantilvered system). One of the beams was about 2" short. I cannot full pen the flanges as I had detailed. The owner does not want to see bolts at the splice and does not want to see the splice plate exposed.(The beams are storefront beams) Is it possible to have a single splice plate welded to the webs of the beam on the non exposed sides? . Has any one designed a welded splice in such fashion.  

 

RE: Welded Splice

a) replace entire beam? It is the steel contractor's problem.

b) I don't think your proposed solution will work because splices generally (to AS 4100) have to be designed for a minimum load of 0.3 x Member Capacity. Check whichever code you are using.

c) Can you change to an extended fin plate connection? This might also not work aesthetically.

RE: Welded Splice

If it's a simple pin support the loss of flanges for the last 2" shouldn't be a problem. Provide a spliced web plate designed for the shear and small maount of bending moment.

RE: Welded Splice

I don't think the problem is very difficult with a little bit of thought.  How large is the reaction?

Best regards,

BA

RE: Welded Splice

(OP)
The location is meant to be a simple pin support, only downward reaction of about 24k. The connected beams are W24x55.

RE: Welded Splice

If it's cantilevered how is it taking only shear and no moment.  Also, if it's taking only shear why would you detail a full pen weld of the flanges?  Have the steel fabricator cut two plates to fit the 2" gap.  Prep the plates and provide full pen welds at top and bottom flanges.  Remove the backer bars after the weld is complete (use a ceramic backer bar if necessary).  Grind the welds smooth, then provide the shear plate on the un-exposed side as you mentioned.   

RE: Welded Splice

Your original statement "I need to design a welded splice at beam to beam connection only taking gravity loads (cantilvered system), and the latest "The location is meant to be a simple pin support" are inconsistant and vague. Please clarify, a sketch may eliminate a lot of guessing and pointless recommendation.

RE: Welded Splice

I assumed the OP was talking about a connection between the end of a cantilevered beam and the drop-in span.  I don't know why he would weld the flanges in that case, though.

If that is the case, a plate welded to the inside of the web on each beam would carry shear and torsion.  Could also fill in with a two inch plate aligned with the webs of both beams and field welded using the first plate as a backer.

A reaction of 24k is not much for a W24x55.  This would be similar to a single angle connection to a column.

 

Best regards,

BA

RE: Welded Splice

A sketch always helps in situations like these.

RE: Welded Splice

BA:

No offense, you could be right on the spot. What I meant was "everybody is guessing to put the puzzle together, the resulting recommendation/comment may not necessarily to the point.  

RE: Welded Splice

(OP)
The beam to beam connection is at the end of a cantilever. The main beam cantilevers across a column and picks up a smaller span beam. The reaction at end of smaller beam is about 24k.
Hope this would help.
I will try to upload a sketch sometime later.

Thanks.

RE: Welded Splice

Well, it't not going to behave the way you expect if you are providing a full moment connection where you are describing a pin.

RE: Welded Splice

Is this how the system looks like?

     ______________________________L_______
     S                 S                  S
     
     
S - support/column
L - link (where splice is needed)

RE: Welded Splice

(OP)
The system looks like as kslee has described.

RE: Welded Splice

Please note the rightmost S was shifted from the right end of the small beam.

RE: Welded Splice

Just out of curiosity, why did you detail (were you expecting) a full pen weld there?  I'm not following the logic of the design - something isn't making sense.  Either you wanted a pin there or you didn't.  If you wanted a pin, then you got what you want.   

RE: Welded Splice

It looks like all you need is a splice to transfer shear. It looks like the propped beam can carry the shear and moment induced. Any comments?

RE: Welded Splice

I agree with you slickdeals, but he did say in his OP that he called for a full pen weld in his detail.  

Kotor-  Either it's a full pen weld (moment connection) or it's a pin (as is showing).  How did you actually design the beam?

RE: Welded Splice

(OP)
Well, the beams were designed as continous beams. The contractor could not get beams long enough to achieve that condition. So we asked them to full pen weld the beams at that location so we could get a cont. beam. However, since the beam (that was meant to be full pen welded) was short, I had to redesign the beam cont upto the "new" splice point and then add the load from the short beam. Luckily, the beams did work.

RE: Welded Splice

What was the shear splice supposed to look like before?  A plate welded to one beam and bolted to the other?  If so, design a longer plate so you can use the same bolt holes.

If it was bolted to both beams, you could do the same thing.

I would not recommend using a plate welded to both beams, since you would not have any mechanism to allow for rotation, providing the pinned support you designed the beam for.

RE: Welded Splice

"Luckily, the beams did work"

The beam "worked" - claim made through confirmation by calculation, or just field observation on the finished/modified product? Load capacity of the "Design" and "as Build" wouldn't be identical, would it (the change) causes long term problem? Please elaborate further.

RE: Welded Splice

(OP)
The cont. beam (with a point load at the newly formed cantilever) do work structurally after new calculations with original design loads.
The smaller beam also is structurally adequate.     

RE: Welded Splice

A 2" gap can easily be filled with weld material.  Use web backing plate and fill the gap with weld.  (Same as full length beam when completed).

RE: Welded Splice

Another possibility, to get around the rotation argument raised by nutte is to use two vertical angles.  The leg parallel to the webs would be welded.  The other legs would be bolted together.  Beam rotation would be permitted by slight bending of the bolted legs.

Best regards,

BA

RE: Welded Splice

If you're trying to achieve a pinned condition, I would not recommend civilperson's suggestion.

RE: Welded Splice

kotor1:

If strength of the beams are adequate, make sure the beam end rotation/deflection at the pin is acceptable. Also, is there any transverse brace to keep the beams stable, side awing could spell trouble.   

RE: Welded Splice

(OP)
The deflection at end of the cantilever is about 0.09 in down(total load). The beams have angle braces attached to the web at 8'-0" o.c that connect to the roof joists.




 

RE: Welded Splice

kslee1000,

A brace to the bottom flange at or near the connection would provide torsional restraint to both beams.  We can't say whether or not it is necessary as we don't know the geometry of the structure.  

An eccentric connection between the two beams does not produce torsion in either beam.  If a double angle is used and the bolts are 2" from the center of each beam, there is a torsional moment (24x2=48k") to be resisted by the bolts, but no torsion in either beam.

 

Best regards,

BA

RE: Welded Splice

kotor1:

Seems you have very good grab of the whole event. Wish you best luck.  

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!


Resources