Tack Welding rebar 1

[Leftwow]

Good morning,

I Have a structural skid for a vibrating pump, we want to saw cut a 3" slab, place the structural skid on the ground, and fill it with concrete. Is it possible to tack weld standard rebar to the structural skid, which mainly consists of W sections?? This is assuming the weld will be used ONLY to keep the rebar in place during transportation.

 

[JedClampett]

Possible-Yes
Good idea-No
Unless the reinforcing is weldable, you're going to have all kind of compatibility issues. And tack welds tend to be pretty amateurish, creating notches in the bar.
If welding is required, go with a weld grade reinforcing and size the welds, even if they're minimal.

 

[Leftwow]

Cool thanks man.

 

[KootK]

I'd tend to be a bit more permissive with this. My thoughts:

1) I have a hard time imagining the tack welds materially affecting the wide flange beams. No worries there for me.

2) If I'm imagining your scenario correctly, you'd be making the tack welds in locations where the flexural tension demand on the bars would be zero/minimal. So I wouldn't be too concerned if the bars develop structural defects at the welds. Who knows, your rebar here may just be T&S governed anyhow.

I'm imagining something like the photo below with concrete deposited into the interstitial spaces.

I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.

 

[Lomarandil]

Is the 3" slab just glorified formwork for the mass concrete?

If so, and like you said, the rebar isn't depended on for the performance of the final skid, I'd be OK with it.

(For other applications, I totally agree with Jed's reservations.)

 

[Leftwow]

Thanks for the reply Kootk and others,

That picture is directly similar to what we are doing.

We are just trying to make it to where they could bring in a rebar mat to the shop and transport it in with like #3 rebar for crack control. What we don't want is the concrete to end up all crumbled up inside the skid if it would happen due to vibration from the pump or perhaps temperature changes. Not to familiar with using beams within concrete, I assume that Steel sections are used within concrete a lot, I'm just not to sure If we could pour 1 foot of concrete inside this thing and it be Sufficient enough to control various modes of cracking.

​

 

[SlideRuleEra]

Unrelated to the rebar issue, it is very difficult to get properly consolidated concrete immediately below the top flange of a beam. You would not think this is the case, but it is. Pay special attention to this detail during concrete placement. Even so, there may still be problems with hidden honeycomb concrete at these locations.

http://www.SlideRuleEra.net

http://www.VacuumTubeEra.net

 

[TehMightyEngineer]

I've seen people use external form vibrators on steel beams embedded in concrete for exactly what SRE is talking about. Never checked to see if it worked to consolidate the concrete below the flange but I don't see why it wouldn't.

Professional and Structural Engineer (ME, NH, MA)
American Concrete Industries

http://www.americanconcrete.com