• To: <seaint(--nospam--at)seaint.org>
• From: Ángel Gómez (megared) <angelgomez(--nospam--at)megared.net.mx>
• Date: Wed, 22 Jun 2005 11:29:42 -0500
```Thanks I reached in the CISC web and sure it will help to calculate Cw.

```
----- Original Message ----- From: "Gary Hodgson & Associates" <ghodgson(--nospam--at)bellnet.ca>
```To: <seaint(--nospam--at)seaint.org>
Sent: Wednesday, June 22, 2005 6:45 AM
```
```

```
```I don't know if this will help you. The Canadian
Institute of Steel Construction published on line
a list of different sections and equations for
their torsional properties. These included a wide
flange or I beam plus a cap channel.  If you can't
find it on the CISC web site (www.cisc-icca.ca),
let me know and I will fax you that particular
section or the whole thing if you want it.
Gary
Ph 905-357-6406
Fax 905-357-4852

On 21 Jun 2005 at 12:14, Charley Hamilton wrote:

```
```> Thanks Charley

This dumped me at a fairly random spot.  Is it the correct web
address? Was there more to it?

> Im using W27x94 + C15X33.9 and they get Lr = 607.47 and the
> reference is AISC table A-F1.1 the question is how they obtain Lr
> for W27x94 + C15x33.9 and Im wondering if  Lr can be solved by other
> method than trial and error showed in  The edition of Design Guide 7
> Example 18.1.3

Oh.  Well, in principle you can compute Cw directly for the combined
shape that is there, then use that computed value in LRFD F1-6, as
they mention in the design guide.  You can compute Cw by formulating
the differential equation for torsion for the combined section.
Personally, I agree with the authors of the design guide:  it's more
complicated to do it that way.

HTH,

Charley

--
Charles Hamilton, PhD EIT               PGR and Lecturer
Department of Civil and                 Phone: 949.824.3752
Environmental Engineering           FAX:   949.824.2117
University of California, Irvine        Email: chamilto(--nospam--at)uci.edu

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