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RE: STAAD or RISA?

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I would have to agree with Gerard on this one with one exception.  Within 2
hours a person who is literate with 2D/3D analysis packages can be running
this program (RISA 2D or 3D) productively...  I have use STAAD, GT-STRUDL,
M-STRUDL, RISA, RAM, and a few other lesser known packages.  RISA was the
quickest to use productively.  For any of these packages the inputs are very
similar... E, I, area, yield, etc...  not much changes here because the
matrix analysis that they use have similar inputs.  Can a high school
student pickup RISA and run it (productively or not) within 2 hours?  Maybe
run, understand the results definitely not...  Someone who has use FEA
(stiffness analysis packages) in the past more than occasionally?  Defintely
yes.... Know all of the inner workings?  Never happen no matter what package
is selected... maybe never even happen if you were one of many developers...
maybe never even if you were the only developer of a specific package...

As with any analysis package you must know what results should be
appropriate.  You should also determine your own requirements to be
comfortable... If you must check every number to 6 decimal places on every
element under every stress and load then you must not have any other work to
do...  Just talking about steel design, probably only a small percentage of
engineers could truly design a beam by hand (to make it even a smaller
percentage, try an unequal flange fabricated section... even smaller
percentage make it tapered)... not using premade tables, actually going
through the chapters in the AISC book and manually applying the sections.
How many engineers know what rT(equivalent) is?  when it is appropriate to
use?  What it accounts for?  Did you know this has been in the AISC book for
the last several versions?  Can you trace it roots back to the publication
in the SSRC guide? ... Just one of many items buried in the AISC book.

Anyway enough of that...

Pros of RISA:  
1. Easy to learn/use.  
2. Newer versions have niced tabulated outputs that can be maximum per
envelope or included each load combination (not sure of manually set page
breaks, but I have never seen them either... could be a limitation).
3. Results have been reasonable on the models I have checked

Cons of RISA:
1. Batch runs are more difficult to do since they are not "built into" the
UI of the program.  These can be done with some work though.  I have made a
VB program which batch ran 6000+ models to develop some in house equations.
2. Input files are text based but are not "text" formated...  i.e. must know
what 30766 is equal to on settings (number made up).  To "map" the input
file can take some time. Once mapped you may have to make small changes when
you upgrade to newer versions... good thing here is each input file has a
version designation so older files can be read in upgraded versions.

Here is what we tend to use:

General stiffness analysis Package:
-----------------------------------
We have RISA, STAAD, RAMSteel, RAMFrame, GT-STRUDL, and probably a few
others in various offices.
I would personally choose RISA.  But if you do a lot of batch jobs then
another package might be better. Use RamSteel for mezzanines and floor
framing (Beams and STD joists).

Tapered member design:
proprietary in-house package... because I have not seen a commercial package
that optimizes tapered sections well enough.

Cold-Formed Steel design:
CFS... Well written program, has some important limitations to be aware of,
Newer windows version is much easier to use/learn than the older DOS based
program.  Author well respected in the CF field.

Concrete/Masonry design:
Don't know, only a few of our departments do this type of design and I am
not part of one of them.

Anyway, I have some decimal places to go check.  Hope this helps.

Respectfully,
Greg Effland, P.E.
KC, MO USA


-----Original Message-----
From: Christopher Wright [mailto:chrisw(--nospam--at)skypoint.com]
Sent: Thursday, September 05, 2002 4:06 PM
To: ?
Subject: RE: STAAD or RISA?


>I believe that no software worth its salt, can be used
> PRODUCTIVELY, without a continuous usage. 
>
Absolutely dead on. I've been using FEA for about 25 years and my 
experience is that it takes no less than 6 months to a year to develop 
methodologies for interpretation and validation and to find and deal with 
input errors. The whole notion of user-friendly and intuitive input means 
the code is easy, perhaps a thrill, to run; there's no connection to 
issues of program errors, mis-interpretation or applicability. 

I've found that no FEA software is only intuitive to the extent that a 
user has a intuitive grasp of structural mechanics and design. FEA 
software may seem user-friendly to a tyro, but the term usually means as 
marketeer-speak for whizzy graphics. By the time a user dopes out a 
fairly bullet-proof (read systematic to the point of being anal) input 
procedure, recognizes program pit-falls, figures work-arounds for bugs, 
and learns to interpret and communicate output and has made enough 
mistakes to do proper sanity checks, user-friendliness is meaningless.

Christopher Wright P.E.    |"They couldn't hit an elephant at
chrisw(--nospam--at)skypoint.com        | this distance"   (last words of Gen.
___________________________| John Sedgwick, Spotsylvania 1864)
http://www.skypoint.com/~chrisw


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