• To: <seaint(--nospam--at)seaint.org>
• From: Ángel Gómez (megared) <angelgomez(--nospam--at)megared.net.mx>
• Date: Tue, 21 Jun 2005 14:39:18 -0500
```sorry  www.aisc.org
and then you go to

```
Well calculating Cw that´s the point and using LRFD F1-6 Lr = ry*X1/ ....
```or trial and error method.
Thank you

Ing Ángel Gómez
angelgomez(--nospam--at)megared.net.mx

```
----- Original Message ----- From: "Charley Hamilton" <chamilto(--nospam--at)uci.edu>
```To: <seaint(--nospam--at)seaint.org>
Sent: Tuesday, June 21, 2005 2:14 PM
```
```

```
```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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