AISC shape properties library naming logic for HSS

Question

AISC shape properties library naming logic for HSS

Ingenuity (Structural)

(OP)

9 Oct 18 10:08

What is the naming logic in RISA 3D in the AISC shape properties library for tubes?

For example: HSS4x4x4, as per below. Why not call the last digit as a "1/4" or "0.25" to match AISC of the same properties?

It is not an intuitive designation, and you have to view the properties box to verify that you have the correct wall thickness.

TehMightyEngineer (Structural) · Answer 1 · 2018-10-09 12:12:31

It's given in sixteenths, 4/16 = 1/4"

STAAD follows the same methodology if I recall; maybe it's just the industry standard and RISA was following along?

Ian Riley, PE, SE
Professional Engineer (ME, NH, MA) Structural Engineer (IL)
American Concrete Industries https://www.facebook.com/AmericanConcrete/

WinelandV (Structural) · Answer 2 · 2018-10-09 12:44:58

IMO, it makes sense to use a whole number representation for the thickness. That way you're not messing with special characters (was it a "_" or a "/" or a " "), and it will sort better - for HSS 4x4, all the thickness will appear in order without any special sorting. But yes, the last number is the thickness in 16th of an inch (like TehMightyEngineer said).

JoshPlumSE (Structural) · Answer 3 · 2018-10-09 15:57:10

Some of the steel database naming convention is based on "legacy" data. By that I mean, you have to think back to 20 years ago when there were greater restrictions on what characters could be used when naming files (or variables used in programs). If they were to build the database from scratch today, they would likely do something more intuitive like you suggest (1/4 or 0.25). However, back in the day, the '/' or '.' would have been problematic.

It gets worse when you talk about double angles....
LL8x8x10x3 is really an LL8 x 8 x 0.625" spaced 0.375" apart
Meaning the 10 represents the thickness in 16ths of an inch and the 3 represents the spacing in 8ths of an inch!

Ingenuity (Structural) · Answer 4 · 2018-10-09 18:58:57

Thanks all, for the info.

Now IF the US was fully metric we would not need to have this conversation...but that ship has sailed...

I appreciate the assistance.

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AISC shape properties library naming logic for HSS