Not logged inAmerican Welding Society Forum
Forum AWS Website Help Search Login
Up Topic American Welding Society Services / Technical Standards & Publications / application of "Reentrant Corner"
- - By Richard Cook (**) Date 04-02-2008 22:43
D1.1 specifies a 1" radius for reentrant corners 5.16, then it gives conditions for the beam copes and weld access holes (3/8" radius, typically 1/2") which has been called reentrant corners also. Would the requirement in 5.16 be applied in all inside corner cuts in all shapes and plate conditions or is there a specific condition. Example, 1) Square hole in web of a beam or girder, 2) Baseplate of column that has an extended section less than the width of baseplate off one side to accomodate anchor bolt holes. I can see the requirement applying to 1) because these corners would be under load but on a baseplate as in 2) all torsional and shear loads would be on the weld of column and plate and then on the anchor bolts.

"Reentrant corner" is not defined nor clarified anywhere I can find. I feel it is not applicable in all siuations, has anyone an answer? Referemces or is this an EOR determination?

thanks
wc
Parent - - By swnorris (****) Date 04-03-2008 11:36
The AISC defines re-entrant, referring to any cope (a cutout) or weld access hole as a cut at an abrupt change in direction in which the exposed surface is concave.

I agree that it is not applicable in all situations, but if you have to cut it, why not go ahead and put a radius in it? A sharp corner in any cope would be less resistant to tearing if it included a radius.  It wouldn't take any additional shop time to add a radius, and it would be less confusing to the guys in the shop when it comes down to determining whether a cope should have a radius or not.
Parent - - By Richard Cook (**) Date 04-03-2008 14:08
And I agree, the situation I have is 4" thick baseplates cut with some inside corners, there is a small radius about 1/4". I have an individual specifying that it needs to be a 1" radius, qouting section 5.16, these are already cut and in production. These corners are outside any load zone of the designed connection. The baseplate is under static, compressive load only. 1" radius is a pretty large radius, equivelent to about a 7/8"
fillet weld. I do not see the need to remake or repair in this situation, we are looking at 4" plate at 4 x 6 foot in size. Do I have any justification in my support? I feel D1.1 is not specific and AISC in turn does not shed light, or would it always be an Engineers determination?
Parent - - By swnorris (****) Date 04-03-2008 14:32
Oh.  Ok.  It's after the fact, and it would require significant repairing.  If the base plate is under static, statically loaded members allow and generally require a smaller re-entrant corner radius than what is allowed for cyclic (see C5.16).  Under these circumstances, you probably need to get the EOR's approval to let them go as is, or approval to add weld metal and shape a smaller radius than 1" with a grinder.  The EOR can modify the code as he/she sees fit, and there's a chance that you won't have to do anything at all.  In the future the easiest thing to do is to have everyone get in the habit of putting a radius in the copes, so there's no issues like this one later on.  That's what we do in our shop with any copes, as pointless as it may seem sometimes; base plates, bent plate pour stops, etc. 
Parent - - By Richard Cook (**) Date 04-03-2008 15:31
Sorry, I should have mentioned such. I have read the commentary and that in it self supports my train of thought. Allthough 5.16 does not mention loads of any type it's clear in the commentary that there are differences and load conditions would be applicable to the decision making process. So as it is, there is no clear answer except for the EOR, I know that the EOR may dictate changes in the standard, but the bottom line, is this an issue, under these circumstance, a desgn consideration or good shop practice? Bombarding an Engineer with questions is not always the best route when the issue should be handled in house. In our situation design drawings did not dictate radius at these locations, as it did at other locations. The detailers did not include the 1" radius, because in their opinion it was not applicable. It hasn't been applied in all the years I have been in the industry, under these circumstances. The sad thing is the individual has the ear of the Engineer, which the Engineer is swayed by his opinion. I have just been looking for something that might persuade this individual my way, I don't see it being "required" under this condition.
Parent - - By 803056 (*****) Date 04-04-2008 14:30
There are times when a repair makes sense even if it isn't required.

Are you interested in having to encounter that same problem time after time or would you like to address it once and have it go away?

Nothing teaches good workmanship practices like having to go back and repair the problem. The more painful the lesson the more likely it won't have to be repeated in the future.

It is a human nature that if you do something wrong, but no action is taken, the bad "behaviour" is reinforced. "Hey, we've been doing it like this for years and no one made us fix it before!"

However, being pulled up short and requiring the repair to be made causes the person to think about the problem and makes it clear that the undesirable behaviour isn't to be tolerated. "I ran into this on my last job. The SOB made us spend ten hours welding and grinding until it was right, I don't want to do that again!" And it's for that reason that I like to follow the policy that  "the individual that screwed it up, fixes it up".

You can tell Little Johnny not to put the folk into the socket twenty times. You can even put the folk into the socket so little Johnny can see what will happen if he does. Most likely Little Johnny will roll over laughing as the smoke rises from your hair. However, pain is a great teacher. The little fella will only push the fork into the light socket once if you let him learn first hand what happens when he does.

Best regards - Al
Parent - By Richard Cook (**) Date 04-04-2008 18:28
I agree all the way, but his situation would not allow for that scenerio. Those that did not put enough radius are not the ones that will have to repair it. Then if the argument between parties of whether it is required or not is not settled, who pays. My best bet is to get EOR approval, I still do not think I need a 1" radius and the small but obvious radius would suffice, my opinion, I'll let the engineer make the final call. Then if he wants it repaired I'll have solid basis for repair back charge.

Back up info not previously given because I didn't think of it at the time and because I was looking for a clarification of the requirement found in 5.16 with the commentary given in C5.16.
These parts were outsourced and are installed at this point, would be extensive field work at my cost if I can't say yea or nay. It is already practice at our facility to put an acceptable radius, it's programed in the system. So it's off to the engineer.

Thanks you guys, I think we all have the same understanding
Up Topic American Welding Society Services / Technical Standards & Publications / application of "Reentrant Corner"

Powered by mwForum 2.29.2 © 1999-2013 Markus Wichitill