ibc 2000 referencing aci318-????? 1

[scherry]

As far as i can tell the IBC 2000 references only aci 318 with no revision listed. therefore are we supposed to design to whatever the latest released edition of aci 318 is that we can find? I would normally expect there to be an adoption process, if i were in a big city, but that will not be the case here. is there anywhere that the IBC forces you into using the latest version of the ACI? I will admit, i have not studied the aci-02 rev yet so i do not know at this point in time what the differences are in regards to tilt up design between this version and the previous one, but I know that load factors changed...so is the load factor and combination data in the IBC still valid for the aci-02??? i will be doing some serious studying this weekend for an up coming project, but any input anyone has would be appreciated.

 

[Taro]

Look on page 675 for referenced standards. ACI 318-99 is referenced.

 

[scherry]

thanks. i had looked and missed it - by a few pages actually. I appreciate the help.

 

[scherry]

Actually i lied - wrote before i looked again. My page 675 in the IBC 2000 has errata, i did find it though - it is on page 597 in my version. thanks again though.

 

[JAE]

Basically, Chapter 35 deals with ALL IBC references.

 

[shemp]

scherry,
The IBC 2000 does modify ACI 318-99. See section 1908 "Modifications to ACI 318."

shemp

 

[haynewp]

I had a discussion with another colleague the other day about the latest code to use. I understand that if you are using IBC 2000, then you should use the exact year of the reference codes it lists. For instance in this thread, ACI 318-99 is appropriate when using IBC2000.

However, I am always seeing drawings where the bldg. code is IBC2000, yet they reference ASCE7-02 or ACI 318-2002 in the general notes for wind and concrete design. I think this is incorrect, however this guy made the argument that you can still use your engineering judgement and select a newer referenced code if you feel that it is more accurate, safe, etc.

Sorry if I am getting off the original thread a little. But I think unless sit down and you prove for instance that ACI 318-02 is more conservative than ACI 318-99 in all instances for what you are using it for, you in violation of the model code and ethical practice.

What are your thoughts on this?

 

[structuresguy]

Well, I think I agree with you haynewp. I think it would be better to stick with the referenced code. I have had experience in Florida with the FBC being behind on code references, particularly with ASCE7. The current FBC2003 references ASCE 7-93, -95, & -98, but not -02. I wrote to the code officials and was told to use one of the referenced codes. Period. Whether or not the new version is "better" seemed to be imaterial. Also, I have had some building officials tell me that ASCE7-02 is not code referenceed, so I can't use it, while others tell me I have to usa the -02 version. Knowing the reality (and the code) makes arguing with the officials easier.

I have also noticed a significant (?) difference between ACI318-99 and -02. THe -02 version allows a higher tensile stress at extreme fiber due to prestressing than the -98 version. I also know that in the next version they are going to reduce it back to its old allowable value. SOrry, I don't have my books here to know what the values are. SO here is a case where they (the ACI commitee on prestressing) have basically said "WHOOPS!" and are changing it back. Knowing this, I would definitely not use the values from the -02 version, as I would have to judge them to be incorrect.

So maybe using the latest version is not always the best. I wish more engineers would take out lines from their specs like "ACI 318, latest version". Use one of the versions allowed by the building code and just list whichever version you ACTUALLY used to do the design.

 

[JAE]

You must use the referenced codes/specs listed in Chapter 35 for your MINIMUM design criteria.

Codes prescribe minimum standards.

So if you want to use a NEWER code/spec that requires a HIGHER level, safety factor, etc. then you as EOR can certainly do so.

But to just reference a NEWER standard that isn't in the IBC code itself is incorrect as the newer standard may be LESS severe and then you are violating the code itself.

 

[structuresguy]

Yes, I agree with JAE. The EOR can always go more conservative, but not less than the minimum required by the building code.

Of course, if you have penny-pinching contractors and owners, you will eventually be called on to justify yourself.