"barely Code compliant" 1

[gwynn]

Just a quick question on my part. I see this and similar phrases thrown around on these forums fairly frequently, and always in a negative vein. My understanding of my job is to provide not only a safe design, but the most economical one. Oviously the first comes foremost. This usually means one or more parts of what I design are going to barely meet Code. I've designed several hundred things by now that barely met Code and have since been loaded to their full specified load, if not more (though in some of those cases I do believe that the Code load factors are overly conservative, but that is a different topic IMO).

At the same time, I have seen many posts where people have opined they are comfortable with 5% overstress on members which is not entirely Code compliant, but does meet standard pratice. I realise that this is partially due to engineers often being over conservative when arriving at loads.

So why do phrases like "barely Code compliant" have negative connatations?

 

[IDS]

So why do phrases like "barely Code compliant" have negative connatations?

I'm not sure that they do; I don't recall seeing that phrase used here.

Perhaps more convincingly:

No results found for "barely Code compliant" site:

http://www.eng-tips.com

site:www.eng-tips.com.

Doug Jenkins
Interactive Design Services

http://newtonexcelbach.wordpress.com/

 

[gwynn]

This is the thread I was reading when I decided to post that. The phrasing is not the same, but it has the same meaning.

http://www.eng-tips.com/viewthread.cfm?qid=350261

 

[BAretired]

"barely code compliant" is not an expression I recall having seen on this forum. If a structural member is designed precisely in accordance with code, it has no additional capacity but it is compliant.

In some situations, it may be prudent to provide additional capacity if the anticipated load is likely to exceed design load or the member is likely to be subjected to unusual abuse during its service life, but normally structural members are designed to just meet the building code and no more.

If some conservatism is desired, it is probably better to increase the specified live load on the area, then design to code.


BA

 

[BigInch]

It boils down to a judgement call. It should happen every day, if you do your job at an operationally competent level. Effectively we're here to walk the commercial line between economics and safety. If we didn't, not too many projects of any type would ever get built. It doesn't take an engineer to design 16' flag poles with 12" pipe. In these cases I always justify and document the reasons (in a design note attached to my calculations) as to exactly why I chose to do whatever I did. If I reached 1.01, or whatever, I explain why I believed the calculations gave me an answer that I believed was conservative and how, in my considered opinion, the finished design does and will meet the intent of the code, regardless of how many decimal places I happened to have XL set for that day. I like BA's idea, reduce the loading by 5 psf and mention in the design note that it does not warrant a recalculation. Even a lawyer could understand that.

Just keep in mind that Mother Nature doesn't have the benefit of ANSYS and doesn't much give a damn about material testing reports.

Independent events are seldomly independent.

 

[IDS]

I presume this is the statement in question:

Also, plate connected wood trusses are designed to "just barely" survive code-level loads, and the plate connections are vulnerable to the slightest deviation in max load, heat exposure, etc.

I think it's open to interpretation.

If it means that they are designed to just comply with all code requirements, then there is nothing wrong with that.

If it means that the trusses will just take maximum unfactored code loads before failure, then they are grossly under-designed.

Or perhaps it means something between those two extremes.

Doug Jenkins
Interactive Design Services

http://newtonexcelbach.wordpress.com/

 

[BigInch]

I can't say for today's wooden truss and anchor plate designs, however I was extensively involved with their design at one time and, while it is true that they were deigned TO code requirements, it did not mean that they did not have enough safety factors to take them to ultimate loads considerably higher than specified in the design codes. We tested many full scale trusses, singularly, and not one failed anywhere near their code load. Tested in groups of 3 or more to 1.5 x code loads, it was difficult to get them to show anything more than excessive deflection. If I recall correctly, the plates themselves had a safety factor on pull-out load of around 2.

Most of any problems we had related to trusses at all were due to perpendicular shear load at the bearing points. Somebody's failure to provide sufficient bearing plate area for the truss, nothing directly related to the trusses themselves. Most problems (excessive deflections) were the result of HVAC contractors actually cutting out the truss' diagonal web members, so they could fit in their ducting work!!! Another from failure to secure against high wind loads by not installing hold-down straps ... and lastly, a tornado that ripped off one of the Pizza Hut roof tops and, strangely enough, deposited it relatively undamaged in the vacant lot across the street.

Failure due to code loads on roof trusses isn't high on my worry list. Increased snow & ice loading due to global climate change.... ya. I'd be worried about that one.

Independent events are seldomly independent.

 

[ornerynorsk]

"So why do phrases like "barely Code compliant" have negative connatations? "

Because adverbs of degree are used judgementally, as if to impart the idea that the speaker does not quite approve of the condition, even though it might, technically, be adequate. It's a self-righteous, belittling tactic.



It is better to have enough ideas for some of them to be wrong, than to be always right by having no ideas at all.

 

[steellion]

Saying something is "barely Code compliant" is like saying someone is "a little pregnant".

 

[bridgebuster]

"So why do phrases like "barely Code compliant" have negative connatations? " - From watching "Holmes on Holmes" although he uses the term "minimum code"

 

[Gumpmaster]

Well,

I'd like to point out that if something collapses, then it was NOT code compliant, not "barely code compliant".

Secondly, the code is primarily a life safety code. There are some serviceability requriements, but not in depth. You can definately have something that's code compliant but doesn't work well. Pre-engineered metal buildings with a lot of deflection with brittle cladding or sheetrock walls attached comes to mind. There are many other examples.

I think as engineers it's our responsibility to not just use the code as a rote document. We need to apply judgement and if something we're designing needs to exceed code requirements to be in the clients best interest, or to meet the clients requirements (even if not explicitly stated "you didn't say the closet door needed to open") then we need to bring that to the attention of the client. Sure, the building won't kill them, but they won't get good use out of it either.

 

[msquared48]

Being "Barely Code Compliant" is kinda like Miley Cyrus, huh?

Do we really want to go there?

Being "barely code compliant" is just another way of saying you have designed to the code minimum, which will change with the next code ass nature reveals itself, so any additions will have to be reinforced, meaning more $$$ spent by the owner in the future.

Mike McCann
MMC Engineering

 

[racookpe1978]

Sure, as long as the idiot building it, and the idiot maintaining it - or failing to maintain it, and the idiot purchasing the parts, and the idiot drilling the hole, and Mother Nature ALL agree to comply "exactly" with the Codes, then "barely compliant" is "safe enough"... The Codes do attempt - more accurately, those who write the codes do try to anticipate these ikely errors and allow for them.

but, the problem is when you try to design 1.0005% of the Code, then have to finagle a way to "think" you are still safe when you see it really is 0.985 of the Code. Even when the thing is "probably" only going to see 0.67 of the design load anyway. But, will it?

Job is to get the piece designed and made so the fewest errors are likely and the most economical safety compliance can be established and maintained for the expected life of the building. But, those highway bridges that collapsed in CA under those 1970-1980 earthquakes? They were compliant with the Code as well, when they were built.

 

[Triangled]

Thinking if it walks like a duck and talks like a duck, it's a duck..... but just barely.

 

[PSlem]

The cashier this morning gave me the right change...but just barely.

 

[BigInch]

I think the phrase sounds worse, if you have a proper understanding of what codes represent from an engineering perspective, rather than from a contractor's perspective, codes define the minimum requirement, which as we know is not sufficient in many cases, especially where a designer does not have a wide imagination. For example, pipeline design codes say you must design for the greatest imposed load, but don't really say what that should be. If I only design for pressure and temperature stresses and those things specifically mentioned in the code and some guy comes along with a wrench and a 5 ft long cheater bar, a 2" thin walled pipe is going to have a problem. I have to add some mechanical strength above what the code mentions specifically. That requires some judgement above what the code says word for word. That can become a huge problem when people try to use codes as the last word on what a contract requires.

I think the real problem is the word "barely". It doesn't sound nearly so bad if you remove that one.


Independent events are seldomly independent.

 

[pinoymaker]

I am not familiar with track homes, but someone I know is. He claims that everything they do are always close to stress level since the material cost becomes significant when they build hundreds of the same houses. "Barely meet code" was the law to be kept employed. On the other hand, I am very much involved in industrial projects. "Barely meet code" does not work very well for us, simply because we do not know exactly what the other teams will need on the building. Being surprised by a new equipment close to submit date is the norm for us. Being able to change the calc. quickly without a redesign is a must in order to keep everything on schedule. Additionally, many clients like to have a little bit of buffer, so that they can add upgrades to their facilities down the road.

It really depends on the application.

 

[msquared48]

The problem with that is that these homes are designed under the IRC which is far less restrictive than the IBC. Inherently, by even the code used, they are designed closer to that magical "line".

Mike McCann
MMC Engineering

 

[BigInch]

If they will never see a more severe service load than the code explicitly defines, I'd find other things to worry about.

Independent events are seldomly independent.