Need a book? Engineering books recommendations...

Return to index: [Subject] [Thread] [Date] [Author]

Re: LRFD Manual Ex 5.1 page 5-12 to 5-16

[Subject Prev][Subject Next][Thread Prev][Thread Next]
Bill,

Your are right.  I should have use lamda_r=13.49.  Not "lamda_p." 
Table B5.1 has no limitation on lamda_p for purely axial compression
on a wide flange.

Thanks for point out my mistake.

Sam


On Thu, 3 Feb 2005 13:01:16 -0800, Bill Allen, S.E. <T.W.Allen(--nospam--at)cox.net> wrote:
> Sam -
> 
> ??
> 
> 0.38*sqrt(29000/50)=9,152 < 9.92, so the flange is noncompact, just like the
> footnote says.
> 
> The 0.56*sqrt(E/Fy)=13.49 is a slender element.
> 
> In the column tables, when it says "Flange is not compact", I don't think
> this affects the axial capacity until you get to 0.56*sqrt(E/Fy) ("Flanges
> of I-shaped sections in pure compression, ..., Table B5.1).
> 
> If I'm reading the specification correctly, the flanges are non-compact yet
> fully effective from (0.38 to 0.56)*sqrt(E/Fy). The issue about being
> non-compact is, again, if I'm reading it correctly, is purely a flexural
> issue. Otherwise, if you exceed 0.56*sqrt(E/Fy), the flange is slender and
> is subject to Eqn A-B5-5, Appendix B5.3a(b).
> 
> Sooo...I think the flange in a W12x65 with Fy=50 ksi is fully effective when
> considering _pure compression_.
> 
> But I could be wrong.
> 
> T. William (Bill) Allen, S.E. (CA #2607)
> ALLEN DESIGNS
> Consulting Structural Engineers
> http://www.AllenDesigns.com
> V (949) 248-8588         .       F (949) 209-2509
> 
> ||-----Original Message-----
> ||From: Szuchuan Chang [mailto:szuchuan(--nospam--at)gmail.com]
> ||Sent: Thursday, February 03, 2005 12:30 PM
> ||To: seaint(--nospam--at)seaint.org
> ||Subject: Re: LRFD Manual Ex 5.1 page 5-12 to 5-16
> ||
> ||On page 4-25, Table 4-2,
> ||Why is W12x65 Fy=50 ksi listed as flanges is non-compact?
> ||
> ||bf/2tf = 9.92
> ||
> ||lamda_p = 13.49
> ||
> ||Is there a mistake?
> ||
> ||Sam
> ||
> ||******* ****** ******* ******** ******* ******* ******* ***
> ||*   Read list FAQ at: http://www.seaint.org/list_FAQ.asp
> ||*
> ||*   This email was sent to you via Structural Engineers
> ||*   Association of Southern California (SEAOSC) server. To
> ||*   subscribe (no fee) or UnSubscribe, please go to:
> ||*
> ||*   http://www.seaint.org/sealist1.asp
> ||*
> ||*   Questions to seaint-ad(--nospam--at)seaint.org. Remember, any email you
> ||*   send to the list is public domain and may be re-posted
> ||*   without your permission. Make sure you visit our web
> ||*   site at: http://www.seaint.org
> ||******* ****** ****** ****** ******* ****** ****** ********
> 
> 
> ******* ****** ******* ******** ******* ******* ******* ***
> *   Read list FAQ at: http://www.seaint.org/list_FAQ.asp
> *
> *   This email was sent to you via Structural Engineers
> *   Association of Southern California (SEAOSC) server. To
> *   subscribe (no fee) or UnSubscribe, please go to:
> *
> *   http://www.seaint.org/sealist1.asp
> *
> *   Questions to seaint-ad(--nospam--at)seaint.org. Remember, any email you
> *   send to the list is public domain and may be re-posted
> *   without your permission. Make sure you visit our web
> *   site at: http://www.seaint.org
> ******* ****** ****** ****** ******* ****** ****** ********
>

******* ****** ******* ******** ******* ******* ******* ***
*   Read list FAQ at: http://www.seaint.org/list_FAQ.asp
* 
*   This email was sent to you via Structural Engineers 
*   Association of Southern California (SEAOSC) server. To 
*   subscribe (no fee) or UnSubscribe, please go to:
*
*   http://www.seaint.org/sealist1.asp
*
*   Questions to seaint-ad(--nospam--at)seaint.org. Remember, any email you 
*   send to the list is public domain and may be re-posted 
*   without your permission. Make sure you visit our web 
*   site at: http://www.seaint.org 
******* ****** ****** ****** ******* ****** ****** ********