Welding on the Webs v Flanges of Existing Steel Beams 5

[sigma1525]

We have designed some supplementary steel members, suporting equipment and piping, to be welded on the web of existing steel beams, this way we avoid cross flange welding and residual stresses. The EOR does not like the idea and insists on welding the members to the bottom (tension) flange of the beams and girders.

Does anyone see any problem with our approach or benefit with his/her approach?

Thank you

 

[JAE]

Depends on where along the beam length you are welding. The web works hardest near the supports and the flanges - especially bottom flanges near midspan, should NOT be welded to as they are in the highest level of tension along the beam.

 

[ToadJones]

Why not bolt?

Agree with JAE about welding on tension flanges. This is especially critical on members seeing repetitive loading.

 

[bridgebuster]

Ditto on JAE's opinion.

Something else to consider: The welding position. If you have to weld to the bottom of the bottom flange it's an overhead weld, which can be difficult. Welding to the web would be horizontal and vertical welds, which are a bit easier.

 

[hokie66]

Did you ask the EOR for his reasons? He may not be concerned about the welding, but rather about the loading. Welding to the web suggests to me that you are intending to apply loads eccentrically to the beams, which may be a torsional problem.

 

[sigma1525]

It is very dificult to explain cross flange welding and residual stresses to ME's via e-mailing. Perhaps, if I direct them to this tread they may be convinced that I am not the only one concerned with welding on flanges of loaded beams.

BTW - The loading is very minor as compared to the steel members with full lateral support of the compression flange. One of them is welded to the web of steel column but they want it on the flanges.

Thanks everyone

 

[hokie66]

Similar to my comment about connecting to the web of a beam and causing torsional issues, the concern with connecting to the web of a column may be that your load is cantilevered, bending the column about its weak axis. Again, why not ask the EOR?

 

[sigma1525]

hokie66.

Simply supported supplementary steel between beams cannot induce any torsion on the existing members and the load on the column is around 150 lbs with a 1 ft moment arm.
Mmax(weak) = 0.175 kip-ft about 10 ft above the base of a W14 column. If that creates a weak axis problem to the them we should post a note for helathy people like myself not to lean against the column. Just kidding....

Thanks for all your comments and advise.

 

[hokie66]

Clear enough now, and I agree with you. Was just trying to guess what the EOR was on about.

 

[paddingtongreen]

There is no question for me, if the web is available for a simple beam connection, that is where it is going. The alternative is to carefully design a partial width weld, especially if it is overhand.

Michael.
Timing has a lot to do with the outcome of a rain dance.

 

[a2mfk]

Wheeeee

http://wwww!

I thought all my steel framed buildings were gonna fall down for a minute there!

I think he just liked the thought of you hanging your miscellaneous MEP stuff from the bottom flange, which is pretty typical via clamps and unistruts, etc. Maybe if you gave him the reactions in the first place he would not have knee-jerked, or maybe you did. Which by the way, would in theory produce more torsion than most web connections...

 

[sigma1525]

a2mfk

You sound just like the EOR in question but what puzzles me is that he is an ME and you are a "STRUCTURAL" designing big steel frames buildings. How can you think the same? Perhaps you can go back and check your steel framed "buildings" for the additional load due to dust buildup......

Thank you