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Re: Avansee Code Check question

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The problem may be that the Lb length (length between lateral supports or
unbraced length) is large. In this case, the cause of failure of the element
is the lateral-torsional buckling.

By default, the Lb length is the flexible length of the member, which in
most cases is the length between the initial and final nodes of the element.

If you want to assign a lower Lb, just enter the value in the Beams/Lb
spreadsheed for the selected elements.

Kind regards,

Boris Kraljevic
P.S. You can request free support at support(--nospam--at)avansse.com.

I believe many structural engineering programs (I am most familiar with
STAAD3), assume an unbraced length equal to the beam length by default. If
you want to specify something shorter (i.e. zero), you need to implicitly
state that.

Regards,
Bill Allen


At 02:17 PM 10/3/98 -0700, you wrote:
>I have downloaded the Avansee program and compared a simple one bay frame
>against a couple other programs. The only discrepency I found is in the AISC
>code check - specifically the bending stress ratio.
>I have written to Avansee to get a response, but wondered if anyone else has
>discovered a problem with this feature.
>Assume the Moment at the node is 63 ft-kips and section modulus for the
>member in the strong direction is 88 in^3 (these are close approximates of
>the W18x50 member used in my example). Avansee indicates that the actual
>bending stress ratio exceeds 1.0 which can not be the case since 63*12/88 =
>8.8 ksi - a far cry from 21.6 ksi allowable.
>I'm curious if anyone else has identified a problem in this module?
>
>thanks
>Dennis S. Wish PE
>
><!DOCTYPE HTML PUBLIC "-//W3C//DTD W3 HTML//EN">
><HTML>
><HEAD>
>
><META content="text/html; charset=iso-8859-1" http-equiv=Content-Type>
><META content='"MSHTML 4.72.3509.100"' name=GENERATOR>
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><BODY bgColor=#ffffff>
><DIV><SPAN class=200293620-03101998><FONT color=#000000 face=Arial size=2>I
have 
>downloaded the Avansee program and compared a simple one bay frame against a 
>couple other programs. The only discrepency I found is in the AISC code
check - 
>specifically the bending stress ratio. </FONT></SPAN></DIV>
><DIV><SPAN class=200293620-03101998><FONT color=#000000 face=Arial size=2>I
have 
>written to Avansee to get a response, but wondered if anyone else has
discovered 
>a problem with this feature. </FONT></SPAN></DIV>
><DIV><SPAN class=200293620-03101998><FONT color=#000000 face=Arial
size=2>Assume 
>the Moment at the node is 63 ft-kips and section modulus for the member in the 
>strong direction is 88 in^3 (these are close approximates of the W18x50 member 
>used in my example). Avansee indicates that the actual bending stress ratio 
>exceeds 1.0 which can not be the case since 63*12/88 = 8.8 ksi - a far cry
from 
>21.6 ksi allowable. </FONT></SPAN></DIV>
><DIV><SPAN class=200293620-03101998><FONT color=#000000 face=Arial size=2>I'm 
>curious if anyone else has identified a problem in this 
>module?</FONT></SPAN></DIV>
><DIV><SPAN class=200293620-03101998><FONT color=#000000 face=Arial 
>size=2></FONT></SPAN>&nbsp;</DIV>
><DIV><SPAN class=200293620-03101998><FONT color=#000000 face=Arial 
>size=2>thanks</FONT></SPAN></DIV>
><DIV><SPAN class=200293620-03101998><FONT color=#000000 face=Arial
size=2>Dennis 
>S. Wish PE</FONT></SPAN></DIV>
><DIV><SPAN class=200293620-03101998><FONT color=#000000 face=Arial 
>size=2></FONT></SPAN>&nbsp;</DIV></BODY></HTML>
>