Steel X-section properties on AISC

[COEngineeer]

I was wondering how AISC rounded their numbers from decimal to fraction to 1/8" increment? I am trying to set up an excel spreadsheet to help with steel shop drawing process. I linked the spreadsheet to Steel x-section property table provided by AISC (depth, web thickness, flange width etc.) The list only has decimal #s. So for example, a W10x22 is 10.2" deep according to AISC. Now if I round it to the closest 1/8 (using mround command on excel), it rounds it to 10 1/4". The manual however says it is 10 1/8".

10.25 is closer to 10.2 compared to 10.125. Do you know why their rounding is not very consistent?

Never, but never question engineer's judgement

 

[Lion06]

I can't say for sure, but I would guess the rounding is always down.

 

[COEngineeer]

No, some of them goes up. I think it is because they only give 1 decimal number instead of 2. So it is impossible for me to create a spread sheet that will automatically look up the fraction # because some of them will be 1/8" off. I just looked up an older ASD and 10x22 is 10.17 instead of 10.2 by AISC.

Never, but never question engineer's judgement

 

[nutte]

That's it, COEngineer. The decimal values are rounded from the actual value. I would expect the actual value to give you consistent results when rounding to get the detailing values.

This is a debate we have with our section properties database. It contains the values from the 9th edition manual, which don't necessarily correspond to the current manual values. Do we dumb our values down to match the current manual, or do we keep the more "correct" values with more significant digits?

 

[MiketheEngineer]

You might use three columns - all manually loaded.

You have a look up column - Say W10x22(characters) and the second column is 10.2''(decimal) while the third is 10 1/8''(characters)

I have done this on many similar databases or spreadsheets and I didn't invent this idea - I copied it. It is a pain - but once done - it works.

 

[COEngineeer]

Well, the data base in the CD that AISC gives out with the manual only has decimal value. I wish they keep it to 2 decimal values. I dont think I have the time and the energy to add another column and put the fraction. Oh well.

Never, but never question engineer's judgement

 

[COEngineeer]

does anyone know where I can get ASD steel member database with 2 decimal places?

Never, but never question engineer's judgement

 

[MarcbSE]

If you are an AISC member you can download the "historic" shapes database. It has multiple decimal places.

 

[MarcbSE]

The "historic" database gives 2 decimal places for depth and 3 for tw, tf & bf.