Software and Codes vs. Specs

[JAE]

I just spoke with one of our software vendors concerning their latest version that we just installed. It seems that their program now performs beam designs for the latest edition of the LRFD Steel Specifications (3rd Edition) only. What prompted my call was my own view that what they were doing was simply wrong and here is why:

1. They allow the user to specify various building codes from various years (i.e. UBC 1994 or SBC 1999).

2. To perform LRFD design, they lock you into the 3rd Edition.

With both of the above being true, There may be times that I simply cannot "meet code" with my design as a municipality or other governing body will adopt a CODE, such as the UBC, which in turn, references a specific material SPECIFICATION. For example, the 1994 UBC refers to the ACI code that existed before the year 1994. Thus, for me to design under the 1994 UBC and then use the new 2002 ACI 318 code wouldn't work....they really don't mesh.

If the new LRFD spec has a design portion that results in SMALLER sized beams than that required by the 2nd Edition, or the 1st, then technically I'm not meeting code and it would be very difficult to even know when I'm not (nothing to compare to).

Just because the new edition is based on latest technology doesn't legally allow me to use it. When I prepare my drawings, I must indicate on the plans that I meet a certain building code so the governing municipality will provide a building permit. I can't do this under this software vendors "method". I want them to keep the earlier versions of the LRFD for me to choose from during design and they don't believe that this is necessary...

Do you agree? Or am I making too much out of this technicality?

 

[austim]

Hi, JAE,

I agree with you 100%, and do not think you are making too much of it.

Partly because of the costs involved (and partly because of my suspicions about the engineering skills of some of the software writers), I have never committed to using design software, but I do on occasions use RamAdvanse. That permits design optimisation to a US code (I forget which, since it is not directly relevant to work done in Australia).

My approach has been to write a post-processor that will take the model data and computed member forces, and then perform a detailed member check to the relevant current Australian code. That way, even when the code is revised, I can quite easily create a new version of my checking routines, and can have the option of selecting which Aus Standard I wish to use. The stress checks done by RamAdvanse also provide a valuable second view of my results, which is quite handy for a one-man office.

(I still program with a 12 year old copy of MS QuickBasic which does all that I need of it, since my member checking does not involve anything particularly exotic in the way of mathematical routines, and I do not need any graphics for the task).

My view is that the optimised design that RamAdvanse can generate will be at least as good as any preliminary design that I would produce, (and probably much better). That makes it a reasonable starting point for producing an
'Australianised' design.

I would hope that the same sort of strategy could work for you.

 

[Ron]

JAE...100% agreement here too
Those guys are just trying to think a bit too much. The practical side is that the most recent code is not always adopted and doesn't have to be. Most jurisdictions have the authority to adopt whatever they want and whenever they want, which creates a need for flexibility on our part in the analyses.

Many times municipalities are several versions behind in their adoption. A good example was that a recent code revision I had to deal with was the "2000 version" of this particular code, which referenced a 1997 subcode, but the 1999 subcode was firmly in place and being used by others.

Sometimes we just need a scorecard!

 

[Ingenuity]

I agree with you too, JAE, and i also share austim's sentiments about "design" software. There are some real black-box type software (GI-GO)out in the market these days and it is scary.

I do more prestressed concrete design - than steel or timber - and the software that i use frequently (which i validated by hand for the typcial structures that i design) supports more than 10 codes (including past codes), BUT most importantly has the provision to "design your own codes" - whilst this can be dangerous for the inexperienced it has proved a god send for me where i can "localize" my design parameters (eg creep and shrinkage data for a concrete mix, load factors and phi factors etc) and so i created a series of "codes" that puts me in control.

JAE, it is also worth noting that in other countries outside the USA, there are National building codes and, IMHO, do not "suffer" like the USA does where currently (unless the IBC takes off) there are BOCA, SBC, UBC - then you say do a steel design - you have AWS or LRFD to choose from - then you may go for a LRFD design, then you have the 2nd or 3rd edition to choose. That is a lot of combinations and permutations.

Seems like we should be getting upset with the code committees and alike too.

That is my $0.02 which is about all i have left after i spend lots of $ on keeping my "library" of codes up to date.

 

[haynewp]

Many of the people who are writing the software we trust aren't even engineers. The quality control is minimal. Ask is they have a hard copy on record of the original code, for a version of the software from 6 years ago and I bet they will say no. How will an engineer defend himself in court if required? Don't be fooled by ISO registration either, it mostly concerns procedures.

 

[ishvaaag]

In my opinion there's more guilt in the public side than in the software developers. Too much codes and nonsensidcal day to day variation making a mess of any practice and code's compliance. A hassle for the structural designers and another to software developers.

Being in the young and developing market of software they don't have as much reins on liability as the millennia old structural designers have.

But the problem is mainly that we are enduring general illegalization of everything (not just structural designs) byt the aberrant practice of changing the law every second.

 

[Taro]

I agree with all of the above replies. The software really should support more than one option for design specification. However, the reality is that the majority of the software I have seen only supports the most current versions of the various design specifications. Can you disclose which software program this is?

Another thing to consider...
Most building codes allow deviation frome the code and use of other rational and equivalent methods if approved by the building official. I would explore whether the building officials you deal with will accept the 3rd edition LRFD. After all, the changes were made for a reason and as responsible professionals, it behooves us to implement current knowledge instead of sticking with outdated approaches. I have found that most sophisticated building officials have no problem accepting current national standards in lieu of the adopted code. And the less sophisticated building officials are usually willing after you educate them.

 

[ishvaaag]

I understand that the right intent of modification of codes and legislation is the best regulation of human activity, but I contend that it is at all with generality in practice so being the case. Much times even in the technical fields this is based on particular whims or fashions, and is general the need of feigning such good intent in front of the public by giant output of legislation. The house where my father was born is maybe over 200 year old -maybe a family property for near 100 years- has walls made of earth work and joists are just peeled trunks, seats 6 m away from a river 6 m lower and shows no signs of any need of abandoning its use, with just refurbishment of the roof made 30 years ago or so.

Besides this, where no code had anything to say, I see lots of failures in current buildings of ordinary standard, and some are notorious in the hi-tech and money end. So I don't eat the junk of putting a limit to MY lack of knowledge by authority, I am worried by THEIR lack of knowledge -btw law makes me and my monies a warranting party of safety-, I don't need to be in the Popov league for that. For buidings are well made on the understanding of the workings ot the natural laws, and not on any political approval or gathering of them.

 

[JAE]

Great replies everybody...just wanted some outside feedback on this issue that "appeared" to me for the first time yesterday.

I've got a call in to the software vendor's director and we'll see how he responds to the issue. I was told by the sales rep that they didn't feel that supporting the multitude of different material specifications was feasible within their program (RAM). But I still think they really have to do so...to keep my business anyway.

Thanks again for joining in. I'll keep you posted as to what they say.

 

[JAE]

Well, they'll keep my business....I just spoke with them about the issue and what they say makes perfect sense:

1. The 3rd Edition of the LRFD did not significantly change any design results other than one strength reduction factor for composite beams...and the change was such that the 3rd Edition was MORE conservative than the 2nd Edition. Other than that, no other changes in the 3rd Edition move your design in the non-conservative direction.

2. With only that one significant change (and it being conservative - correcting a non-conservative flaw in the 2nd Edition) they decided to simply use the 3rd Edition for any designs that use LRFD and not distinguish between the two.

This makes sense. As long as the newer material specification is MORE conservative, we as designers are OK. And in this case it was only one item.

He mentioned that if in the future, the LRFD Spec. changed dramatically, that they would most likely have to address the issue of different material specs linking with different building codes and giving the user options.

(Very quick response from them, which I appreciated - compared to other vendors that have been discussed in this forum....)