## Corner Radius of HSS Shapes

## Corner Radius of HSS Shapes

(OP)

Anybody know where to find out how much of a radius different HSS shapes have at their corners. I know this depends on the thickness of the tube wall. In the welded joint tables, the flare bevel weld shows that the radius C is three times the thickness, which could be 1-1/2" for a 1/2" thick wall. Is this right? I haven't seen a lot of half inch wall tubes to recollect how big of a radius it had on them. Is there any where you can find this information?

I have wanted to know this radius several times over the last couple of weeks, so thought I would finally ask.

I have wanted to know this radius several times over the last couple of weeks, so thought I would finally ask.

## RE: Corner Radius of HSS Shapes

In the green AISC Steel Construction Manual (1989 ASD) take a look at the Tubing Dimensions and Properties on pages 1-94 - 1-103.

If you look at the very bottom of every page you will see a note that says "** Properties are based upon a nominal OUTISIDE corner radius equal to two times the wall thickness". If you notice this is used for ALL TUBE properties they have listed in all of these tables. (Area, Moment of Interia, Section Modulus, Polar Moment of Interia, and Z.)

Although the green 1989-ASD is a code that is still used by many engineers the dimensions and properties for all of the structural tubing should still be the same in the LRFD codes that now specify the same tubing with a HSS designation.

I hope this helps.

Jeffrey A, Krus P.E.

## RE: Corner Radius of HSS Shapes

As a follow-up to my earlier post you may want to also look at page 1-155. This is the allowable mill tolerances permissable.

On the right hand side toward the middle of the page you will see:

Radius of Corners - For a square or rectangular structural tubing, the radius of any outside corner of the section shall not EXCEED three times the specified wall thickness.

Based on this and my previous post would suspect that using 2 times the wall thickness for engineering calculations would be reasonable.

If you are doing some sort of fit up or clearence job you can expect the outside radius to be 2 times the wall thickness and no larger then 3 times the wall thickness. This is where you need to use your judgment depending on what you are doing.

Jeffrey Krus P.E.

## RE: Corner Radius of HSS Shapes

## RE: Corner Radius of HSS Shapes

Also, you may not want to design anything using TS properties, as I'm not sure they're even manufactured anymore.

## RE: Corner Radius of HSS Shapes

## RE: Corner Radius of HSS Shapes

Do you neglect the different K values for W shapes from the ASD to 3rd ed. LRFD? No, you cant. The weights are the same, but if you're detailing, you'd better be using the properties out of the 3rd ed. LRFD.

A HSS/TS example-

HSS8x8x1/4

A = 7.10

I = 70.7

S = 17.7

Z = 20.5

TS8x8x1/4

A = 7.59

I = 75.1

S = 18.8

Z = 21.9

## RE: Corner Radius of HSS Shapes

The shapes are both fabricated under the same ASTM - it is because of the TREND in fabbricating these things closer to the lower bound thickness that AISC felt that the phi factor was not adequately accounting for the allowed variation - so they created the HSS shape to deal with it.

When you say that "the thickness of the TS shapes and the HSS shapes is not the same" - you should be saying "the thickness of rectangular tube sections fabricated some years ago varied in the + and - allowables, but now the rectangular shapes tend to be fabricated in the - zone only and AISC has adjusted the properties to give us a better measure of strength to reflect that."

A fabricator could make a rectangular shape and call it EITHER a TS or an HSS and still meet the ASTM requirements. Its just a name change to reflect a need to adjust calculations - its not a name change that required any different fabrication methods.

## RE: Corner Radius of HSS Shapes

The Green ASD book is STILL a valid code to use for design but its becoming outdated and will soon be updated with the new LRFD/ASD steel manual release in 2005.

Until the 2005 book is released the green 1989 ASD and the 2000 LRFD codes are valid. I've stated in my earlier post word for word with page numbers taken directly from the green 1989 ASD manual.

Since I do not use the LRFD method, can anyone provide the SAME information word for word (as I did for ASD) with page numbers from the 2000 LRFD Manual?

By doing this DEL 2000 can make his own educated decision with references to BOTH codes.

Jeffrey Krus P.E.

## RE: Corner Radius of HSS Shapes

2000 LRFD should be 1999 LRFD with 2001 LRFD Errata suppliment.

I cannot wait until the 2005 manual is released it will save lots of confusion between these codes.

Jeffrey Krus P.E.