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

RE: braced frame - double angles in ETABS

[Subject Prev][Subject Next][Thread Prev][Thread Next]
Gina,

What version of Etabs?

If you are using the new version 7.+, you probably should use 97 AISC
Seismic Code as your design code rather than the UBC.

Is it X-braced? If so, your unbraced length may utilize the intersection
rather than diagonal distance along the entire brace.

Your stitch plates may be the problem - is Etabs treating each angle as an
individual rather than a double angle? The stitch plates allow you to design
assuming a single member rather than two pieces.

Hope that helps.
-gerard

-----Original Message-----
From: Gina Gobo [mailto:GoboGT(--nospam--at)c-b.com]
Sent: Wednesday, January 23, 2002 5:16 PM
To: seaint(--nospam--at)seaint.org
Subject: braced frame - double angles in ETABS


I have a concentrically braced frame modeled in ETABS. Most of the brace
members are double angles. I have posed this question to ETABS and am
waiting for a response. I thought I would email the server to see if anyone
has any input on this.

My brace members (double angles) are coming back as "too slender" when I
complete a lateral analysis using 97UBC-ASD. When I do a hand calc of the 97
UBC slenderness requirements for Zone 3 and 4, the members are ok. I have
set the unbraced length ratio in ETABs, but cannot seem to get the analysis
to get past the slenderness issue. Can anyone provide some insight on this?

Gina


******* ****** ******* ******** ******* ******* ******* ***
*   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
******* ****** ****** ****** ******* ****** ****** ********