Need a book? Engineering books recommendations...

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

Re: General Building Code Question

[Subject Prev][Subject Next][Thread Prev][Thread Next]
Cliff,

>From a general point of view, you should have in theory no problems using
newer editions of standards that are refereenced, since they supposedly
represent more "advanced" knowledge.

>From a strict point of view, however, I would argue that if the older
standard (ACI 318-99 in your example) contains something that is more
conservative than the newer version of the standard (ACI 318-02 in your
example), then you likely are required to use the standard that is
actually referenced (which is more conservative in this case).  If it is
the other way around (i.e. the newer standard is more conservative) then
it would be fine to use that newer standard, especially since the building
code represents the "minimum" and there is nothing saying that you cannot
do something more conservative than what the code requires.

As a result, I tend to use the standards that are actually referenced by
the model building code.

FYI, there are some MAJOR differences between ACI 318-02 and ACI 318-99,
so your comment that concrete design is not really effected by the edition
of ACI 318 used is not as true for this change of editions as previous
editions.  You are correct that changing from ACI 318-95 to ACI 318-99 was
not too much of a change to the basics of concrete design.  That is even
true for going from ACI 318-89 to ACI 318-99.  But ACI 318-02 now has
different load factors, the unified design provisions that were Appendix B
in ACI 318-99 are now in the main body of the code which means that
flexural and axial member design is different, and techincally you are no
longer able to use working stress design (was Appendix A which is now
replaced with strut & tie method).  There are other major changes that
don't effect main stream design as much, but are still there (anchorage in
Appendix D, changes to chapter 21 for seismic design, etc).

HTH,

Scott
Ypsilanti, MI


On Mon, 28 Oct 2002, Cliff Schwinger wrote:

>
> This is a general question but I will ask it by giving a specific
> example.
>
> IBC 2000 references ACI 318-99 for concrete design.  Does the reference
> to ACI 318-99 mean that engineers are bound to using this specific
> edition of ACI 318?  For most aspects of concrete design it does not
> make much of a difference as to which edition of ACI 318 is used;
> however sometimes there some significant differences between the new and
> old editions that can have an impact on member design.
>
> Here is why I am asking:
>
> ACI 318-02 allows flexural tension stresses in post-tensioned flat
> plates to be as high as 7.5 x (f'c)**0.5.  Prior to ACI 318-02 the upper
> limit on this value was 6 x (f'c)**0.5. Since IBC 2000 specifically
> references ACI 318-99, I am assuming that engineers are not permitted to
> take advantage of the higher service level tension stress.
>
> Am I correct with this assumption?
>
> Thanks.
>
> Clifford Schwinger P.E.
>
>
> ******* ****** ******* ******** ******* ******* ******* ***
> *   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 
******* ****** ****** ****** ******* ****** ****** ********