Need a book? Engineering books recommendations...

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

RE: Tall stud wall framing / IRC rant

[Subject Prev][Subject Next][Thread Prev][Thread Next]
I agree with the statement that "If you use a code (whether
engineered-based or prescriptive-based), it is still the user's
responsibility to read all of it and understand it."  But I also agree
with Jordan that code based design tables should either be based on the
most common design condition or should be based on a conservative
design, with footnotes defining how to modify the table for other
conditions.  The code should be written to minimize errors in usage - if
the tabulated values are unconservative for the majority of
applications, the code is contributing to the potential for erroneous
designs.  While it is incorrect to use tables without reading the
footnotes, we must recognize that not all users will do as detailed a
review as is intended, so the tables should minimize the potential for
unconservative designs.  

I also think that this thread points out the need for detailed design
calculation checking.  A good checker will check code interpretation and
design approach, in addition to checking the math.  Two sets of eyes
looking at the code will increase the probability that the footnotes
will be considered.  I also do not think that such checking should be
left up to the building department - design checking should be as
essential part of structural engineering, before being submitted for
building department review.  The errors noted in this thread were caught
because someone did check the designer's assumptions - how many
structures have been built and have potential design errors because the
design was never fully checked? 

William C. Sherman, PE
(Bill Sherman)
CDM, Denver, CO
Phone: 303-298-1311
Fax: 303-293-8236
email: shermanwc(--nospam--at)cdm.com

-----Original Message-----
From: Scott Maxwell [mailto:smaxwell(--nospam--at)engin.umich.edu] 
Sent: Saturday, August 27, 2005 6:28 PM
To: seaint(--nospam--at)seaint.org
Subject: Re: Tall stud wall framing / IRC rant

Bingo.  Exactly.

If you use a code (whether engineered-based or prescriptive-based), it
is still the user's responsibility to read all of it and understand it.
Misleading is not necessarily unclear or conflicting.  If the table in
question was written so that it was unclear or the requirements could
not be agreed upon in general, then that is one thing...but that does
not seem to be the case.  It seems that it was a matter of not reading
the whole thing (misleading as it might be).

But, then that is just shots from the peanut gallery.  ;-)

Regards,

Scott
Adrian, MI

On Sat, 27 Aug 2005, Christopher Wright wrote:
>
> On Aug 27, 2005, at 12:18 PM, Jordan Truesdell, PE wrote:
>
> >  Oh, I don't disagree that the table is accurate. I believe that it 
> > is misleading.
> I've been through this with piping codes. You're looking at the 
> difference between an engineer responsible for familiarity with the 
> codes and someone whose responsibility is something else.
>
> Every design provision that was ever set out is conditional on 
> something else--you can't just pick things from a book, unless you 
> know the limitations. I had a guy who neglected to account for the 
> buckling strength of a vacuum vessel. He kept alibi-ing  that he 
> didn't screw up because he'd done calculations correctly. In fact he'd

> 'accounted' for the internal vacuum by doing pressure stress 
> calculations as if the higher pressure was inside. He was deeply 
> wounded when I told him that his engineering was crap, so his 
> arithmetic was irrelevant. Same with your contractor--he consulted the

> code, which is OK, but he didn't know enough to understand what it was

> telling him, which is not OK. That's why engineers have to keep up
with their schoolwork.
>
> Christopher Wright P.E. |"They couldn't hit an elephant at
> chrisw(--nospam--at)skypoint.com   | this distance" (last words of Gen.
> .......................................| John Sedgwick, Spotsylvania
> 1864)
> http://www.skypoint.com/~chrisw/

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