Wide Flange Welded Beam Splice 2

[RM87]

Hey folks,

I've been having a bit of a hard time designing a full-capacity moment beam splice between two wide flange beams of the same size.

I'd like to design a splice that accounts for the maximum moment that the beam can sustain to avoid having to track loads of the existing structure.

Existing W12X35 beam w/ welded beam splice - I've proposed a welded plate splice at the top flange, bottom flange, and at the web.

Any suggestions would be helpful.

Thanks,
RM

 

[RM87]

Please see the attached image for a better idea of what I'm trying to do.

 

[racookpe1978]

For that much effort (4x plates on all available surfaces), why not do a simple bevel weld prep on each of two flanges and one web, and require a full-pen weld? You're having to prep all four sides, plus the edges of the tie plate, so the time is near comparable to make the joint.

Lifting requirements? Travel and transport? even up on the H-beam on site, its not that much different.

 

[dik]

If you want to weld plates as you have shown, flip them over and cut the nailer to accommodate the plate on top... lot easier welding.

I'd normally do a full penn weld as racookpe noted.

Dik

 

[RM87]

Any concern of weakness in the joint? What do you guys think?

At this point, I'm pretty invested in finding out how to do this calc. Any tips? Templates?

 

[gtaw]

Your welding symbol indicates the fillet weld extends "all around", but I seriously doubt there is sufficient access to accomplish that.

The electrode should be able to bisect the angle at the apex of the two members if there is any hope of achieving fusion to the root of the joint. The web plate and the two bars under the top flange do not provide the access needed to deposit the fillet welds specified.

Next, you specify "all around". Once again, there is little chance the welder can do what you specify due to limited access between the two ends of the wide flange beams.

A direct splice between the two members is the better detail if you have welders with the ability to weld grooved joints. Assuming the base metal is carbon or high strength low alloy steel and provided the filler metal matches the strength of the of the beam, the allowable stress on the CJP weld is the same as the allowable stress of the base metal assuming AWS D1.1 or AISC are the governing design documents.

If the application is for static loads, backing can be used for the CJP groove welds and left in place once the weld is completed. The CJP groove weld has the added advantage of higher allowable stress when compared to a fillet weld.

If the connection is critical, that is there is no alternate load path should the weld not perform as expected, I would recommend the CJP groove welds be subjected to ultrasonic examination. The fillet welded option should be or could be tested using magnetic particle examination.

Best regards - Al

 

[RM87]

Thanks for the recommendations - CJP groove welds seems to be the best approach.

However, can someone lend me some pointers on how to do the calculation with welded splice plates? How would you run the calc?

Thanks,
R

 

[dhengr]

RM87:
Dig out your Engineering Mechanics, Strength of Materials, Steel Design and Welding Design text books out and do a little reading and review, you should have a fair idea how to do this problem. And, you always have to think, can I physically weld it or assemble it, while you are doing your design. Why don’t you reread the above, and give it some thought, and then tell us a few reasons why the CJP is the better way to weld the two WF’s together to get full strength of the WF’s for that joint. What should that weld joint look like at the flgs. and at the web, and how should it be preped? Do you have to back gouge the welds and reweld? Do you have to grind the welds smooth, why, why not? Is half this beam already in place and you are just trying to add length to it? Will this be done in a difficult position, out of position?

What is the moment in the WF’s where you are making the splice? Draw us the shear and moment diagrams for your beam. Is it the full moment cap’y. of the member? What is the force in the t&b flgs., and the forces in the web? Show us what the bending normal stress looks like on that cross section, and show what the shear stress looks like across the depth of that member. Why aren’t your splice plates sized properly? There are several reasons. What should their areas be, what about their length and why’s that important?

Note that this kind of welding, particular field welding should not be being done by the carpenters second string helper.

 

[RM87]

Thanks all for the suggestions~!