Preheat temperature for 2.48" thick A992

[Prestressed Guy]

Ok, time to split hairs.
Given an A992 beam with a 2.48" flange (W27x368) what preheat temperature should be called out?

Per D1.1 Table 3.3
1½" to 2½" inc. preheat to 150ºF
over 2½" preheat to 225ºF

So, by the book preheat to 150ºF. BUT... if it was 0.03" thicker, it would need to preheat to 225ºF. That is a mighty big change in temperature for a very little difference in thickness.

What say you, 150º, 225º or something in between?

 

[driftLimiter]

It says up to and including 2.5" I think you would be safe using 150F. The question is more pertinent if you had say 2.52". But it seems to state clearly that 2-1/2" = 150F.

 

[Prestressed Guy]

I agree that "by the book" 150º is compliant. I was more wondering about is it rational for that 0.03" difference in thickness to result in a 75º change in preheat.

I am inclined to bump the preheat up some but not to 225. My gut is saying 175º but was looking for a sanity check.

The weld will be to add a web doubler which will be sized to allow the plate to be back beveled to clear the flange root fillet (k-tf) and still have sufficient thickness to allow a partial pen weld to meet the VQ/Ib demand.

 

[structSU10]

Anytime you are near a hard boundary it gets fuzzy. Similar problem when determining a seismic site class. It is more than likely that preheat was established for the upper bound of each section so it is always conservative for its given range.

 

[Prestressed Guy]

Thanks.
I am currently up against one of those hard boundaries on Seismic. I have a parking garage which if it was two blocks south of its location would be SDC D but at its actual site, it is SDC E.