ibeam - radius fillet area - whats its name?

By aevald

Date 03-30-2015 08:40

I'm going from memory only, but I believe that it is referred to as the "K" area or region. Best regards, Allan

By 123weld (*)

Date 03-30-2015 13:27

thanks, i called it the "k section", but didn't know if that was slang or formal, or whether it was even close to right. thanks for your help

By aevald

Date 03-30-2015 16:20

Well it sounds as if others have "cleared up and addressed" your question very well and with a lot more detail and back-up data as well. As usual(and this is a good thing), I too am better informed now, however, my memory will still not likely remember all of that great information. Best regards, Allan

By welderbrent (*****)

Date 03-30-2015 13:30 Edited 03-30-2015 13:32

Good morning 123 and Allan,

The radius itself is the 'k'; the area on the web for 1 1/2" from the edge of the radius up the web is the 'k-area'; the area on the flange for 1/2" out from the radius is 'k-1'; the whole thing is often, though I'm not sure at the moment if it is a technical application, referred to as the k-section.

Now, the k-area is what is the critical area. That portion was put under extreme stress during the rolling and is partial to cracking, lamination, and other problems during welding of Heavy Beam Sections, those over 2" thickness. This is of concern in D1.8 for Seismic applications with Demand Critical welds. D1.1 does not consider 'k' in any way but I still don't like to see welding there.

He Is In Control, Have a Great Day, Brent

By welderbrent (*****)

Date 03-30-2015 13:40

To continue a bit,

If you look at the requirements in D1.8 for the corner clips of stiffeners, connection plates, continuity plates, etc you will see that they take the k into consideration to keep the welders from 'accidentally' welding in the k-area.

As mentioned, D1.1 does not mention k but it makes for a good learning moment to teach welders that they are less apt to make a mistake if they always stay clear of 'k' even though they can't always leave an 1 1/2" up the k-area. Just good practice so they always think about it.

It is important to note as well, if the k-area 'accidentally' gets welded into, we can in no way 'demand' the weld be removed. AND, the code says not to and explains that too often more damage is done removing than was done by welding. Bad air-arc practices, or just no talent, bad grinding, etc does more in leaving stress risers than the weld does in the first place.

We are instructed to report it to the engineer and let them decide how to proceed.

He Is In Control, Have a Great Day, Brent

By SCOTTN

Date 03-30-2015 14:12 Edited 03-30-2015 14:50

Great points. I don't like to see welding there either. In fact, in the 14th ed. of AISC's Specification For Steel Buildings, Table N5.4-3 of the newly added Section N requires that when welds are made on doubler plates, continuity plates, and stiffeners in the K-area, the web K-area must be visually inspected for cracks within 3" of the weld, regardless of whether it's a seismic application or not. Cracking in the K-area of hot rolled wide flange shapes was initially believed to be either the scrap iron or the continuous casting into near shape that caused the problem, but it's actually the final cold straightening that alters the steel properties in the K-area. Extremely high yield stress almost equal to the elevated tensile strength occurs with corresponding lowered elongation and single digit CVN toughness. Continuity plates and stiffeners placed in the webs of rolled shapes should be detailed to show clipped corners along the web to extend 1 ½” beyond the published k detail dimension and a dimension not to exceed ½” along the flange, beyond the published k detail dimension. This is to eliminate any welds in the k area, which have the potential to crack due to rotary straightening of the steel at the mill, which may result in a reduction in ductility and toughness, an increase in hardness, yield strength, ultimate strength, and an increase in the ratio of yield to ultimate strength.

By aevald

Date 03-30-2015 16:22

And thank you as well SCOTTN, good information to know too. Best regards, Allan

By aevald

Date 03-30-2015 16:21

Thanks again Brent, I knew some of you other folks would step-in and assist with this one. Best regards, Allan

By CWI7611 (**)

Date 04-05-2015 01:52

What do you call the area in an H beam? You guys ever see any of them?

By welderbrent (*****)

Date 04-05-2015 16:29 Edited 04-06-2015 13:34

I wonder if you are commenting because we 'assumed' by 'I-beam', that the OP was asking about WF beams.

There are 'I-beams' separate from 'WF beams' but for the most part 'H beams' are WF beams. AISC breaks some things down for rails and describes the various differences but we probably did answer wrong for a true I beam.

Gotta get going to Church. Will see about adding tomorrow while my books are handy.

Brent

By welderbrent (*****)

Date 04-06-2015 13:56 Edited 04-06-2015 14:02

So, with AISC 14th ed in hand: (Sorry for not taking notice and commenting about the OP's use of 'I-beam' earlier, much of the earlier posts' information may have been totally out of the context of what the OP wanted)

Structural shapes come in many varieties: channel, angle, plate, HSS, etc.

Beams, as normally termed for description, come in 5 overall separate identified products. W-, M-, S-, HP-, and for sake of arguement, crane (train) rails. The first 4 fall into the 'H' shape classification by AISC. Even though 1 in particular is often referred to in slang terms as 'I' beam, a term which many not in the structural end of things also call almost all beams.

WF= Wide Flange, both inside and outside of the flange surface is basically parallel. Generally what is used for the bulk of structural work for columns and beams. For the most part, an 'H' shape and termed such by AISC.

M-shapes= are an 'H' shaped member not classified as W, S, or HP. May have a sloped inside flange face or other feature that does not fall into standard criteria.

S-shapes= (American standard beams) have a slope of about 16 2/3% on the inner flange surface; what many refer to as 'I' beam but also called an 'H' shape by AISC.

HP-shapes= (bearing piles) similar to W-shapes except their webs and flanges are of equal thickness and the depth and flange width are nominally equal for a given designation.

And of course, crane rails= rails for cranes and much like train rails. Have often been used to make anvils and such out of. Not in the 'H' shape category but added for detail to help some understand who may not normally deal with these items.

In all 4 cases of the 'H' shapes the radius area at the flange to web transition is referred to as the 'k'. For the most part, only the W shapes will have consideration of k, k1, k-area, and/or k-section for any welding and even then it is only of major consideration when used in Demand Critical/Seismic applications.

Hope I cleared up the waters and didn't just make things muddier.

He Is In Control, Have a Great Day, Brent

By SCOTTN

Date 04-06-2015 14:25

I hear people refer to WF shapes all the time as I beams, so I didn't think about it when the OP mentioned I beam, though as you said, it's still the k-area.

By CWI7611 (**)

Date 04-16-2015 01:19

Thanks, that takes a "load" off my mind and puts it on my back. Now I just have to figure out of the choices you gave me what people have used in the past. fortunately most of the time the flange and web sizes were well defined in the drawings. Normally what I always worked with started with the flange at one thickness and gradually thickening toward the web. So I guess this is where I have always differentiated, if the flange was the same thickness to the web, I had always called them "H" beams.

Thanks for your explanation.