Design Calculations (Generation/Review/Storage)

[WpgKarl]

Was wondering if anyone can offer some wisdom on how you handle the generation, review, filing & long-term storage of your engineering calculations?

Some thoughts:

1. Paper (hand) calcs -> in pen or pencil? (Pen fades after a while?)
2. Simple wl^2/8 quick checks versus detailed finite element modelling (napkin check to protect from garbage-in = garbage out errors?)
3. Design spreadsheets versus Mathcad (never used it, but heard it is really good)
4. Do you pdf all calcs and store?
5. Separate calcs for preliminary / final design as well as design review?

If you can point me to a previous thread, that would help as well.

WpgKarl

 

[MiketheEngineer]

Usually in pencil. Keep copies of all calcs, printouts, everything etc in job folder. A lot of it would also be on computer and it is backed up nightly. Hold on to it for so many years - Check with your lawyer on "Document Retention" criteria

 

[JedClampett]

1) Pencil
2) Depends on the complexity of the structure. Many times wl^2/8 is all you need. Other times, a full blown STAAD run is necessary.
3) We have internally generated spreadsheets done in house for routine tasks. Very slick. They look like very neat complete hand calculations.
4) Our librarian does.
5) I keep preliminary work in the calculation volume (after the formal calculations) with other backup information and sketches. I see no harm and some good in knowing how the design evolved.

 

[dik]

I guess I should be doing them in pencil, but I use ink...

Dik

 

[ash060]

I make too many mistakes to use ink. But any errors I find in pencil I cross out with ink and redo in ink that way I know where the error was made and what it was.

 

[dik]

I just cross out the ink... I make 'revisions' too...

 

[ash060]

I like that 'revisions', errors is just to harsh of a word.

 

[bones206]

I agree, much to too harsh ;-)

 

[Spanky7]

We are required to strike out initial and date the change per our companies proceedure.

 

[corus]

Pen or pencil? Which century is this? I use mathcad for calculations as you can see the formulae, and give a ready check on units, and your arithmetic. If you don't have that then use SmathStudio which now has units too.

Tata

 

[sdz]

This is the Century of the Anchovy!
Mathcad is OK if you have your own copy or you are a permanent employee but for transportability I prefer to do my calcs in Excel. Keep macros to a minimum, preferably none. You should be able to export to open doc format if necessary.

Electronic calcs make communicatingwith other offices and making a pdf for storace much easier.

 

[IDS]

I prefer to do my calcs in Excel. Keep macros to a minimum, preferably none

Do you prefer to use your car without starting the engine as well?

Avoiding spreadsheet macros seems like working with one hand tied behind your back to me.

Also in my opinion there should be more emphasis on review and checking of the end product, rather than a detailed check of the design process.

Doug Jenkins
Interactive Design Services

http://newtonexcelbach.wordpress.com/

 

[jenofstructures]

1. i used pencil for my manual computations so it will be at ease if i made some mistakes

2. wl^2/8 can be used for a preliminary design

3. Excel is better than Mathcad specially the 2007 version because of the advancement on drawings, graphs and formulas. You can even make a drop down list on it (like the different reinforcement and its areas)

4. Sometimes we need to pdf our calcs, so that our clients can not accidentally change its values.

5. I keep my preliminaries as well

Poems are made by fools like me, but only God can make a tree. engineers creates wonderful buildings, but only God can creates wonderful minds

 

[sdz]

Here's a sample

 

[rowingengineer]

Doug,
I agree and disagree with you.

I agree the end result checking is far more productive in finding problems than reviewing of the design process.

I disagree about macro's, keeping with your car analogy. While Marco’s is a higher order calc method and probably a better car it is only required when on the highway doing 200 km/hr, in the back streets doing 40km/hr it consumes to much fuel and makes you late for work.


An expert is a man who has made all the mistakes which can be made in a very narrow field

 

[csd72]

sdz,

wow, good old AS1170 I used to know that code like the back of my hand.

1. Definately pencil
2. as many wl^2/8 calcs as you can get away with. I sometimes just use the computer for deflection and to double check the accuracy.
3. Spreadsheets if I do a lot of them.
4. Hard copies are useful if there are mino changes.
5. I keep the preliminary calcs until the file is archived then I will clean out everything but the final set and pertinent contact notes.

 

[diarmud]

I'd consider keeping your final files very small and limited. I would not show crossouts or preliminary calcs, sketches.

Keep only what is required per your state board.

Attorneys love delving through files that have crossouts, prelimins that are different from finals, etc. You may have a good explanation for all of it but at times, they amy have your lunch.

KIS is the way.

Regards