ASCE 7-05, 7-02, 7-98 Confusion 4

[therattler]

The Florida Building Code (2001/2002 Revisions) references "ASCE 7" - thanks a lot. Are any of them 7-05, 7-02, 7-98 acceptable? Only the latest? What are most engineers using? Is there a consensus on this that I don't know about?

Same question - International Building Code.

Thanks

 

[JStephen]

The general rule is to always use the latest unless something specifically calls for particular version.

 

[SlideRuleEra]

IBC 2003, Chapter 35 "Referenced Standards" specifies ASCE 7-02

IBC 2000, Chapter 35 "Referenced Standards" specifies ASCE 7-98

http://www.SlideRuleEra.net

 

[ArneG]

I'd have to disagree with JStephen.

In structural engineering it is very important (law) to use the current code incorporated by the governing code agency, whether its State, City, etc.

If in doubt contact the local (usually city) code official for the proper code reference.

 

[rholder98]

Note that the 04 FBC--not the 01--is now the governing code in Florida. It references ASCE 7-02.

 

[JStephen]

ArneG, you aren't disagreeing with me. Read the second half of my response, which is exactly what you are saying.

SlideRule, you bring up a a very interesting point. I see in Chapter 35, it lists these standards and "the effective date". What exactly does an "effective date" mean? The obvious reading is that a referenced standard that had an "effective date" five years prior could have been used in conjunction with that building code for those five years prior as well, even if the building code from those years didn't list it yet- which implies usage is not limited to the year listed. The wording used in Chapter 35 doesn't specifically limit the usage to that year, and it's really not clear if that's the intent or not. If that is the intent, they probably need to actually state it somewhere.

By way of contrast, in thumbing through my ASME B&PV code, I find a table titled "Year of Acceptable Edition of Referenced Standards in This Division". Here, the intent is quite clear, to reference a particular year, no later, no earlier.

In my ASCE-7-02, Section 9.14.2.1 lists the ASME B&PV Code "Including Addenda Through 2000" as a concensus standard to be followed to the extent referenced. But the ASME code itself mandates when sections become effective (6 months after issuance of addenda, with annual addenda), and you simply don't have the option of using an older version, regardless of what version IBC or ASCE list in their references. I would be curious to know how many of the other references in Chapter 35 have similar provisions. Particularly in the case of something like a "Safety Code for Elevators", it would seem ill-advised to insist on an outdated version.

 

[WillisV]

A follow-up regarding the Florida Building Code:

The original FBC 2004 referenced ASCE 7-98 despite in many other ways being identical to the IBC 2003 (which as pointed out references ASCE 7-02.)

The 2005 supplement to the FBC was just recently (within the past few months) approved. It is this supplement that revised the reference to ASCE 7-02.

http://www2.iccsafe.org/2004_florida_codes/

 

[JAE]

I've always taken the IBC Chapter 35 to specifically call out a particular year edition of a reference. I think this is evident because currently, all these code/spec writing bodies have begun to cross-correlate their texts to better correspond to the IBC codes. In fact, ACI even changed their publishing years to better align with the IBC issue years.

 

[jen4950]

Look in the referenced standards section of the FBC-04. I've been down this road- just follow the standard that is referenced in the back of the Florida Code that your project is under.

I'm finishing up CA work on a project in Florida using FBC 2001.

"The general rule is to always use the latest unless something specifically calls for particular version." - NOT a General rule in my book- that's dangerous in my opinion; especially if you have more than one engineer (experienced or not) working on the same project.

I would recommend NOT arbitrarily mixing and matching codes and standards because you're too lazy to follow the one referenced in the specs and CD's- and follow thru with associated references (for blatantly obvious reasons). Perfect example -> 1.4D+1.7L vs. 1.2D+1.6L - so a "smarty pants" engineer getting the loads for a load take-down would conviently use load combos from one code and the other "smarty pants" engineer designing the memebers would use strength reduction factors (knowingly, or not) from another. The scary and obvious part here is when they don't talk or document. The important aspect of following the governing code and referenced standards to a tee is that it covers you- and your colleagues; especially from yourselves. If you follow the code and version, you don't open up the chance to really screw up.

 

[JStephen]

Well, Jen, it's not my intent to be lazy, smarty pants, or dangerous. However, you also seem to be overlooking the second half of that sentence, "unless something specifically calls for a particular version".

The flip side of this issue is that I have seen contract documents and design calculations referencing standards and building codes that were twenty five years or more out of date. You can go through some cash trying to keep up to date on these things, and if you don't need them often, it's easy to get behind.

While the original question asked about FBC & ASCE-7, I really do think that you'd run into problems of logical consistency trying to apply this all the way down the line with those references in Chapter 35. Where a code references standards, and those reference other standards, and those reference other standards, you lose a year or two at each layer, and at some point, something's got to give. (Does the ASCE-7 ever reference IBC, by the way? If so, it would be an older version than the one that referenced ASCE-7...) I see on the ICC website that you can submit requests for committee interpretations; this would be a good one for that.

 

[JAE]

ASCE 7 never references "up" to the model codes...its always in the other direction.

Chapter 35 of the IBC (don't know about the FBC) directly references specific documents that have specific issue dates.

In section 102 of the IBC it states: [blue]"The codes and standards referenced in this code shall be considered part of the requirements of this code to the prescribed extent of each such reference. Where differences occur between provisions of this code and referenced codes and standards, the provisions of this code shall apply."[/blue]

I don't think there's really any doubt or logical inconsistency involved when you use a required effective date standard referenced in Ch. 35. They should be used if a jurisdiction has adopted a specific code with a Chapter 35 included and using "other" standards with different effective dates than shown in Ch. 35 DOES result in logical inconsistencies.

 

[JStephen]

Example: Chapter 35 of the 2003 IBC references AISC-ASD, including Supplement No. 1. Supplement No. 1 references ACI-318-99. Meanwhile, IBC references ACI-318-02.

Interesting too, is that this Supplement says "Where codes and standards are referenced in this Specification, the editions of the following listed adoption dates are intended" and includes a table of issue dates. That's the language that is missing in IBC.

 

[JackTrades]

While we all need to be aware of the written authority upon which we base our designs, in some cases the overarching authority is physics and engineering state-of-the-art. Case in point: The 2004 FBC bases WL analysis on the ASCE 7-02 which does not provide guidance on hip roofed open structures. On the other hand, the new ASCE 7-05 includes a detailed methodogy (taken from New Zealand standards, I believe) that provides for a rational analysis of such. Should we disregard this code based advancement until the 2005 ASCE 7 is accepted by the FBC?

What I've done in this circumstance is to analyze such structures with the methods available in both ASCE 7-02 and ACSE 7-05 and note on the plans that I've done so and applied the worst case results to the structure. I do the ASCE 7-02 analysis for the lawyers and the 7-05 analysis as an engineer.

I guess we're all para-legals now.

-Jack

 

[JAE]

JStephen,

I guess I don't see how a long string of references which appear to ultimately conflict somehow voids out all the highly specific references in Ch. 35.

Simply because they included AISC ASD (a very old - not updated steel spec) and ASD references - in a very limited extent - an older ACI code than the one found in Ch. 35, doesn't then logically mean that we can all assume that the dated references in Ch. 35 can be taken at leisure and we can pick and choose the standard that we want - or the even the latest standard.

There are many jurisdictions who don't always agree that simply because there's been updated research and new code concepts that those are necessarily "better" and should be used. I know that in California the 1997 UBC met with much resistance over its seismic criteria and many qualified structural engineers showed in journals and articles how some of its provisions were incorrect, or overly conservative.

So if a jurisdiction adopts a specific code, which specifically references other documents, then those specific references should be used.

The other thing to keep in mind here is that a standard or specification stands alone as a complete document. What I mean by this is, for example, that ACI 318-02 and ACI 318-05 are NOT simply different issues of the SAME specification. They are completely distinct and stand-alone specs. and should always be treated as such. To see 318-02 listed in Chapter 35 and then say - its just 318 and chapter 35 doesn't specifically say I have to use the 02 version is to muddle the fact that 318-02 IS the 02 version. The date is not an afterthought, its integral to the spec's identification.

I agree with your second half statement "unless something specifically calls for particular version" - I just think that Ch. 35 DOES specifically call for a specific version -despite examples of some stretched out references chains which seem to conflict.

 

[JStephen]

JAE, here's where I typically see stuff like this. I've got a spec book from a recent job, and it has "Standard General Conditions of the Construction Contract" included in it, from ACEC/NSPE/ASCE. I find a paragraph that states "Reference to standards, specifications, manuals or codes of any technical society, organization or association, or to Laws or Regulations, whether such reference be specific or by implication, shall mean the standard, specification, manual, code or Laws or Regulations in effect at the time of opening of Bids....except as may be otherwise specifically stated in the Contract Documents." I flip through the book, and here's a reference to "ANSI Standard B58.1-1961". Now, presumably, they've updated that standard in the 45 years since it was published, and the reference to it would be taken in light of that general paragraph above, and would not be taken to mean you had to hunt up a 40-year old copy of that standard in order to build the item. That's my "general rule" from above.

On the other hand, as I've noted, ASME B&PV Code and AISC-ASD spell out very clearly that specific years of certain references are the ones to be used.

You mentioned that ACI 318-02 and ACI 318-05 are NOT simply different issues of the same specification. I notice on the cover of my ASCE 7-02, it says "Revision of ASCE 7-98". In the Abstract, it states "ASCE 7-02 is a revision of ASCE 7-98". However, these phrases are missing on the ASCE 7-05 version. (It does state "This revision of the standard began in 2003...") So there may be some confusion on the part of the writers themselves as to whether these are or aren't different issues of the same standard. I do see that ACI-318-05 "supersedes" ACI 318-02. "Supersede" is to render obsolete, inferior or outmoded, to make void, to make superflous or unnecessary". "The 2005 code revised the previous standard "Building Code Requirements for Structural Concrete.."" from the commentary.

 

[JAE]

Good examples. I don't disagree with your general points that there is some confusion. Here at Eng-Tips there have been previous threads where individuals advocate simply using the latest-greatest code - and I've always tried to point out that you should use the adopted provisions - which start with the building code and then reference out from there - specifically using chapter 35 and the dated editions specifically. I guess I don't see why there is so much need to say "We here at the IBC hereby dictate that the issuance year that we have printed is the year you should use". If I see ACI 318-02, jeesh..just use 318-02.

Generally, the codes (specifically I'm talking about the IBC) have gotten a lot better about tightening up their references and coordinating between agencies, though, as you pointed out, you can chase down multiple references and find a seemingly logical conflict.

And yes, I'd say that in a general sense, ACI 318-05 is a revision to 318-02 - (standing on the shoulders of giants, etc.) but legally, technically, they are specific and different documents which shouldn't be flippantly interchanged...that's really my main point.

 

[JStephen]

I thought y'all might be interested- I did send an informal inquiry in to ICC on the matter. The response was that yes, the specific years referenced in that chapter are the years to use, and they may not be the latest versions. The code development people have to review a version of a referenced standard before it gets listed in Chapter 35, and if they haven't had a chance to review it, it doesn't get listed. The years are only shown in Chapter 35 so they don't have to update text in the rest of the code each time a standard updates.

 

[Ron]

therattler...The FBC as well as IBC and others provide a specific reference chapter to the standards that are applicable within the code. As JAE and others noted, Chapter 35 for the IBC does this and also in the 2004 FBC, Chapter 35 provides the applicable date of the standard. As WillisV noted, the 2005 supplement was adopted in November 2005 which brings the current reference to ASCE 7-02.