Welding steel post bases (over concrete)

[dcg9381]

I'm providing structural support for an LVL in my residential garage. Support is via 2x2 square tube steel, 3/16... Compressive load calc on steel (as near as I can tell) appears to be vastly superior to wood, even twice the size.

This is a photo of the footer on my 2x2 tube. It's painted in epoxy temporarily to keep the steel from rusting to the concrete. The issue I'm having, I'm experiencing warping when welding the base in..

Should these plates be places first, then the post welded in place? If so, kinda hard to keep paint on the steel while being welded... I suppose they could be welded in place, pulled, painted, then put back..

 

[welderjosh]

If you're doing it per AISC the baseplate won't sit on the floor but rather leveling nuts on the studs and then grouted in. What are you using for anchors? You should be able to pull a 3/16" plate flat to the floor if you have correct anchorage.

 

[readhead]

It's going to warp no matter what you do unless you go to 1/2" plate. Just bolt it down, it will be fine. In my business we would usually set it on shims, tighten the nuts and then non-shrink grout would be placed under the plate. We do that to provide some adjustment to hit a specific elevation at the top. What kind of fasteners are you using in the concrete?

 

[strutaeng]

Standard practice is to "shop weld" baseplates to columns.

Ultra rare to have baseplates in the field. I recall doing a job were baseplate had single anchor in the middle and post fit directly over baseplate and was **** welded...steel erector was not happy.

For little baseplates with light loads direct attachment with concrete anchor bolts is fine. Heavy baseplates supporting building columns will typically be leveled and grouted.

 

[dcg9381]

Thanks, guys.. I haven't decided on anchors, this is "inside" and apparently doesn't have a lift component associated with it. That is, the LVL doesn't have to be secured to the concrete in the event of a "wind event". I was just planning on putting 3" 3/8 anchors into the concrete - expansion type. I'm sure I can "pull" the plate tight to the concrete, wasn't sure if I was doing it wrong.

I'm doing this on a larger scale outdoors for a deck, those will be secured by 5"-6" galvanized Titen HD Heavy Duty Screw Anchor, 1/2" diameter minimum. Those posts do have a lift component... I'll do the plate in 1/4".

 

[gmwelder86]

Typically in the shop would tack welder or clamp to fitting table to keep from
Pulling. 3/8 wedge anchors will probably pull it flush. More worries about what’s being done for corrosion resistance on the bottom that will be in direct contract with concrete.

 

[jkeyser14]

It's warping because you put too much heat into it all at once. If you want to weld stuff like this without it warping you need to weld it in smaller "stitches". Place very short welds on each side of the post, then let the part cool fully before adding more short sections of weld. Make sure to weld opposite sides each time you weld, or your plate can warp to one side. When welding very different thicknesses of parts together, it may even be necessary to control the cooling rate using an oven or welding blanket, but you shouldn't have to do that here.

 

[sberry]

Want it flat, they got a special tool caled a hammer.