Spreadsheets for Cold-Formed Sections?

[Gary L. Hodgson and Assoc.]

List,

Does anybody know of any excel spreadsheets for calculating the section
properties of cold-formed steel sections? I already use CFS from RSG
Software (http://rsgsoftware.com/) that gives me what I want, but I'd
prefer to do all of this within Excel.

I tried creating my own spreadsheet but I found it too time consuming.
Any help would be greatly appreciated.

cheers,
Gary

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[Adair, Joel]

Gary --

I think you may have already found your answer -- to use CFS, because
developing your own spreadsheet is too time-consuming. My experience
has been that, if there's commercial software that does what you need it
to do, it's nearly always cheaper to buy the software than it is to
develop, verify, and troubleshoot your own in-house "software". At $595
for CFS, you'd have to develop a working alternative in probably
something like 3-6 hours of time that would otherwise be charged to a
client. I would think even if you know light-gauge design inside and
out, and are a wiz-bang spreadsheet programmer, you'd probably be
hard-pressed to do that. (Of course, if work is slow, and you need
something to do, spreadsheet development or other "sharpening-the-saw"
activities are a good use of time.)

If you want to do your light-gauge section calcs within Excel because of
interaction with other parts of your design workflow, then you might
consider buying the CFS DLL from RSG. You could have it do the
gruntwork of the calculations, and just write a Visual Basic
user-defined function that takes input from the spreadsheet, calls the
DLL, and returns the results of its calculations to the spreadsheet.
That would be a far simpler programming exercise on your end that might
justify the additional expense of buying the DLL.

-- Joel Adair
SHW Group
Plano, TX

List,

cheers,
Gary

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[Martin Li]

Gary:

I have one. Please confirm your email address (des...@hodgsoneng.ca). I
will email it to you.

Martin
Email: m...@tb-engr.com

[Bill Allen]

Shouldn't one verify the algorithms of any black box software?

That is the reason I prefer to write my own spreadsheets, not because it's
more cost effective.

All of the formulae one needs for CFS is in the AISI Design Manual (one of
the best design manuals since Blodgett, IMO)

Of course, that could be one reason why I'm not Rich and Famous (tm).

:o)

T. William (Bill) Allen, S.E.
ALLEN DESIGNS
Consulting Structural Engineers
V (949) 248-8588 . F(949) 209-2509

-----Original Message-----
From: Adair, Joel [mailto:jad...@shwgroup.com]
Sent: Wednesday, July 29, 2009 7:02 AM
To: sea...@seaint.org
Subject: RE: Spreadsheets for Cold-Formed Sections?

[Salvador Dorado]

Gary,
I know RISA 3D calculates properties of cold-formed sections.

[Adair, Joel]

Of course one should verify the software. But I can do that much faster
than I can WRITE the software.

I guess it also depends on what the required functionality of the
spreadsheet is. If all Gary needs to do is calculate section properties
of a simple built-up shape, a spreadsheet will do the trick. If I
recall correctly, though, CFS does some pretty sophisticated stuff --
allowing you to add stiffening bends in the sections, variable bend
radii, lip dimensions, etc. If he needs all that functionality, a
spreadsheet would require some pretty complex logic.

A lot also depends on one's approach to spreadsheet design. A basic
nuts-and-bolts spreadsheet for a simple repetitive calculation doesn't
take long. For a complex spreadsheet requiring a lot of logic, though,
I usually do most of the calculation in a VBA routine, because it's so
much easier to control the logical branching (if this, then that, but
not if it's this, but for this third case, do the other...).
Spreadsheet formulas for complex logic so common to design get difficult
to audit. For these types of spreadsheets, I usually find that I spend
about 20% of my time writing the part that actually does the number
crunching, and the other 80% organizing the input and output into the
format I want, making the spreadsheet idiot-proof, adding bells and
whistles (drop-down menus, radio buttons, toggles, etc.) and debugging
and testing. The basic number-crunching part usually gets done to the
point of just being useable to satisfy immediate project demands, then
the rest happens in spare time later. I try to make it as user-friendly
as possible, so if I distribute it around the office, I don't have to
explain to everybody, "It won't do this, and if you want to do that, you
need to input it like this...". It also helps when I set it aside for a
while, then need to use it a year or two later.

Obviously, everyone needs to decide for themselves where to make their
investment -- in time spent developing a tool or in money buying one.

[Conrad Harrison]

Gary,

I have VBA functions for cold-formed steel design to AS4600, mostly matches
AISI:1996. But I have only setup calculation of section properties for
c-sections and combinations of: nested, back-to-back, boxed.

For other sections we have CFS. There is also CUFSM by Ben Schafer at John
Hopkins University, along with plenty of tutorials and theory.

http://www.ce.jhu.edu/bschafer/cufsm/

Then there are worked examples in Greg Hancocks books on cold-formed steel
design: these are tabulated approaches to calculating section properties, if
you know how you can setup circular references in Excel worksheet and force
iteration to automatically find the solution.

At Excel Calcs there is also a spreadsheet for calculating section
properties of apparently any shape. But I haven't had time to work through
and see what it does, and it uses US units so little value to me.

http://www.excelcalcs.com/

At Exel calcs will find my entire VBA function library: schTechLib.xls.

Regards
Conrad Harrison
B.Tech (mfg & mech), MIIE, gradTIEAust
mailto:sch.te...@bigpond.com
Adelaide
South Australia

[Gary L. Hodgson and Assoc.]

Martin
This is to confirm my e-mail address. Thanks very much for your help.
Gary

[Gary L. Hodgson and Assoc.]

Bill and Joel,
Thanks for the replies. I was checking some of my early work and that's
when I decided to see if anyone else had already done this. I am using
the AISI formulas for the section properties. Joel, as you mentioned I
want to achieve interaction with other parts of the design. Presently
when designing storage racks, I model them in SODA ( a 2&3D steel design
and analysis program) and determine the lateral deflections which I then
use to determine the period of the racks and the seismic loads, using
Excel. Then, back to SODA to apply the seismic and notional loads along
with gravity and wind (if any) and get the results. I then check the CF
sections using CFS to see if they are satisfactory. If not OK, then do
it all over again. It is time consuming.
As a lot of the racks are repetitive, I can analyse them using a
given beam load of say 100lbs per foot and create a library of member
forces which can be pro-rated. I can then use Excel throughout the
process, if I can solve the member loadings and stresses using Excel.
Then I would just check my results using CFS.
My problem is I am not a whiz-bang programmer. I don't know
anything about VBA except that it is used with Excel. I also have never
heard of CFS DLL but now I will search for info.
Perhaps that is the way to go. An engineer acquaintance at a large
storage rack firm told me they use RISA and CFS.
Thanks for your input and I may come back to you with questions if you
don't mind.
Gary

[Gary L. Hodgson and Assoc.]

I forgot to add that with all the rain we have had this summer, I have
had all sorts of time to play with my spreadsheets.
Gary

Gary L. Hodgson and Assoc. wrote:
> --------------------------------------------------------------------------
>
> Your following message has been delivered to the list
> sea...@seaint.org at 06:46:18 on 30 Jul 2009.
> --------------------------------------------------------------------------

[Gary L. Hodgson and Assoc.]

Conrad,
Thanks. I am going to look into both of these when I can find the time.
All of the engineers in this area(Southern Ontario) are busy. I have
two customers who are in the storage rack business, and one is quite
busy and hence I am also, along with all my other customers. That's is
why I
want to put everything into Excel, rather than 3 programs(SODA, CFS and
Excel). I may be day-dreaming.
I also have a thing about US units. Living so close to the border,
most of this area(Niagara Peninsula) has clung to Imperial but all our
Canadian codes are in metric. Further from the border, the use of
metric increases. On the other hand, so much technical help comes from
US sources. I end up working in both systems. Frustrating. Another
day-dream is that the USA will go metric, and I will also win the
lottery to-night.
Gary

[Scott Maxwell]

You have better chance of winning the lottery. <grin>

Regards,

Scott
Adrian, MI

On 8/1/09 9:21 AM, "Gary L. Hodgson and Assoc." <des...@hodgsoneng.ca>
wrote:

> Another
> day-dream is that the USA will go metric, and I will also win the
> lottery to-night.
> Gary
>
>

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[Drew Morris]

The lottery will occur long before metrification. I had heard a story
about a Congressman complaining to the Federal Highway Administration
about the use of metric units and wanted to know why they were in meters
instead of feet. The FHA replied because Congress passed a law in the
1970's mandating the use of metric units.

Gary L. Hodgson and Assoc. wrote:
> Conrad,

> On the other hand, so much technical help comes from US sources. I
> end up working in both systems. Frustrating. Another day-dream is
> that the USA will go metric, and I will also win the lottery to-night.
> Gary
>
>
>

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[David Topete]

The same goes (metric vs. imperial) for most DoT  and DoD projects...  It just the way it is...  It'll take an act of Congr-

--
David Topete, SE

[Gary L. Hodgson and Assoc.]

Well, I did not win the lottery Sat night, so here I am again. One of
the sources pushing for some metrication is your military. Whenever
they go anywhere, they come up against shrugged shoulders when they try
to order supplies, etc in Imperial or US units. That's why they came up
here to see how our CanStds Assoc handled metrication. I was there.
Gary