Our Building Codes - Good, Bad, or Ugly? 13

[BuildersEngineer]

What do YOU think of our building codes, the IBC and IRC?

I've been publicly critical of the International Codes over the years. Well, someone at the ICC finally saw one of my articles and lashed back with a letter to the editor:

This letter is in response to a two-part piece I wrote concerning minimum rebar requirements in foundations. Here are the two articles:

Part 1, Minimum Rebar In Footings, from Structural Engineer Magazine, January, 2013

Part 2, Minimum Rebar In Foundation Walls, from Structural Engineer Magazine, March, 2013


Of course the ICC would disagree with my opinion that their publications are convoluted and confusing. But to suggest that I be banned from voicing that opinion in the future is downright un-American.

How do you feel about the IBC and IRC?

* Are they user-friendly?
* Do they produce consistent results from user to user?
* Can you find what you're looking for easily and quickly?

I'll post the results from this poll on my blog at BuildersEngineer.com

Thanks for you time.

 

[lexpatrie]

Having actually submitted a code change proposal or two (both of which died) attempting to simplify how a mathematical expression was presented, and seeking to clarify the units (to me a square foot to the 1/2 power is a real puzzler), it does not take that much time to do a code change proposal. That's a weak excuse. I work for a small company, I can spare an hour. You have enough time to troll the internet message boards for engineering, you have enough time to do a code change proposal.

The problem is the yield - an hour for nothing.

We'll see what happens to my latest - an attempt to get a minimum connection in IBC into IRC (or vice versa, I forget).

Code users are in the best position to improve the code, as they are actually using it. Submit them when they arise.

If you follow the proposed changes, you'll notice there is one person who seems to submit about thirty code change proposals a cycle, all of which are of little value.

And then we have the great sprinkler lie - where it was approved despite "will not change the cost of construction" box being checked (to my recollection, I may be wrong).

--Brian.

 

[Archie264]

So let me get this straight: submitting something that was completely ignored and changed nothing was worth an hour of your time?

Besides, if I could change regulations with a simple letter we'd have a flat tax in short order.0

And I don't consider my participation here "trolling", thank you very much. It's a forum though which to exchange ideas with, and get help from, peers, and to learn from online mentors. Hardly a waste of time, in contrast, I would suggest, to your proffered submission to a code-regulating body that publicly asked a profession journal to stifle dissent, reminiscent of any tin-pot dictatorship throughout history.

 

[hokie66]

Archie,
The letter was not from the code body. It was from an engineer who used his connections to the ICC and the Florida Board to demonstrate his importance. Whether or not those bodies knew of his action, I don't know.

 

[lexpatrie]

Archie - read what I wrote, please.

 

[JStephen]

One other minor snafu is that any revisions made will go in an upcoming edition, if incorporated, whereas the problem may be in an older version (ie, ASCE 7-98). So whatever gobbledygook was in the old version is in there to stay and you're stuck with it.

 

[dozer]

I was on a code writing committee several years ago and I can tell you the guys writing the code, including myself, often forget that the users of the code don't have the advantage of sitting in the room with the other code writers and listening to the explanation of where they are trying to go with a certain paragraph. I mean after a 30 minute discussion everybody agrees that its clear and then they move on. How can they really expect some poor schmuck all by himself with no one to get feedback from to glean what they intended?

 

[woodman88]

I think the problem is that they are working very hard at trying to look like they are doing something.

Take the load combinations changes for wind from 2009 IBC to 2012 IBC. Wind in the Load combinations using strength design or load and resistance factor design went from a 1.6W to 1.0W. In the Load combinations using allowable stress design wind went from W to 0.6W. Guess what 1/1.6=0.625 so they merely changed the factor from one set of equations to another set of equations.

The important factor is removed, but now there are three wind maps.
Looking at the equations in the 2009 IBC you have p<net> = q<s>K<z>C<net>[IK<zt>] where q<s> = 0.00256V^2 Section 1609.6.3 and Table 1609.6.2(1) for an equation of p<net> = 0.00256V^2K<z>C<net>[IK<zt>]. The 2012 IBC you have p<net> = 0.00256V^2K<z>C<net>K<zt>. Since the I value is gone and the V values change (see 2009 IBC figure 6-1 and 2012 IBC figures 26.5-1A, 1B & 1C).
For the difference Categories you have
Cat. _______ 2009 IBC V^2(I) ___ vs _____ 2012 IBC (0.6)V^2
____________________________________ (at 0.6W with all the other factors being the same.)
I ________ 90^2(0.87) = 7047 ___ > _____ 105^2(0.6) = 6615
II _______ 90^2(1.0) = 8100 ____ > _____ 115^2(0.6) = 7935
III & IV __ 90^2(1.15) = 9315 ___ > ______ 120^290.6) = 8646

For a minor decrease in the wind loads.

Looking the ASCE 7-05 (as referenced in the 2009 IBC) to the ASCE 7-10 (as referenced in the 2012 IBC) you will see the same thing happening.

Garth Dreger PE - AZ Phoenix area
As EOR's we should take the responsibility to design our structures to support the components we allow in our design per that industry standards.

 

[ImminentCollapse]

User Friendly: So-so
Consistent Results: No
Easy to navigate: Yes, with experience, which is probably the same for Law, Medicine, running a McDonalds, etc, etc.

Regarding question 2, having observed and been involved in contentious disputes, it has amazed me how two equally experienced, qualified “experts”, can thoroughly, and convincingly argue different interpretations of the code and how it impacted a particular design/construction flaw or failure. What this means, I’m not entirely sure, but it does speak to consistency and repeatability.

IC

 

[briancpotter]

woodman88-

Disregarding all the other reasons for the wind provision changes (one of which being it more accurately reflects what the wind speed actually is), a "small" reduction in wind loads is nothing to sneeze at. Even considering the added cost of extra engineering time and re-writing software, it probably amounts of a savings of millions of dollars over the course of the thousands of buildings that will be built under those provisions.

Brian C Potter, PE

http://simplesupports.wordpress.com

 

[frv]

I disagree, briancpotter.

Your position assumes structural design involves "continuous" functions. I'd say design is "discrete". Let me explain: If you get say, a 5% reduction in wind loads (and that is an the high end of what the change is for the vast majority of the country), you are not suddenly going to begin spacing rebar in walls at 11.4 in on center instead of 12" o.c. You are not going to start using 2x4's instead of 2x6's, etc. Or changing the spacing of wall studs from 16" to 15.2".

I do understand that the committees are genuinely trying to reflect the most accurate research. I think, however, that they have begun missing the forest for the trees. The complexity of the codes primarily affects the engineer (and architect); not owners or contractors. The onus is on us to make sure we muscle through all the minutiae of every little exception, change, and trigger, the end result being designs not all that different from designs of 20 years ago.

Engineering, unfortunately, is becoming a commodity. In an environment of ever increasing competition, the increase in code complexity is straining either the profitability or the adherence to the newer codes in many firms.

I'm not suggesting we stop research of stop updating codes. But I think we should be a bit more cautious and deliberate with changes. Before we update a provision for a 2% lower load, let's think about ROI for the engineer, not just the contractor.

 

[Archie264]

lexpatrie, I apologize, I was out of line.

Regarding the codes, I know I value the old code and reference books on my shelves. They weren't perfect, of course, but I have an easier time understanding them.

frv, I think you and Brian might be getting at the same point in a different way. That is, a 5% reduction might have value for, say, a truss or bar joist manufacturer, but for most practicing engineers it is of little to no value and might be a detriment. I know I have no interest in skinnying down the design to it's absolute bare minimum, and even less interest in spending hours to figure out what that bare minimum might be.

 

[dhengr]

Codes should not be an end in themselves, they should be as clean and as simple as possible, a means to an end, and that is safe infrastructure design. Code writing and publishing and the univ. research that feeds it should not be a larger and larger cottage industry to the detriment of actually getting the infrastructure designed and built with public health and safety and the economic use of materials in mind. We don’t need new editions of codes every three years, and we don’t need ref. codes all being out of synchronization with each other either. Nobody can begin to keep up with this crap any more and do his job well, in terms of the actual design production and quality of design. We are not really designing safer or better structure than we did thirty years ago, but we are working twice as hard to do it. Just look at the questions we get here on E-Tips. Half the time the OP’er. has no idea of the big picture, or what he is really designing but he has started a big debate about whether R-sub-bvq should be multiplied by 1.57 or 1.59 because it is a Thursday and it’s raining; and no one really even knows what Rbvq is or where it came from.

Throughout my career, and a good share of that has been spent critiquing bldg. and other structure failures; I haven’t seen many instances where some fine point (an elaborate code improvement?) was missed and caused the problem. But, I have seen plenty of instances where sheer stupidity, lack of fundamental understanding of how the structure works, or out and out incompetence has caused the ultimate problem. And, I don’t think we can ever codify those things out of the equation. But, we can police them out, by not allowing incompetents to do this work. Good Structural Engineering and design has always required good engineering experience and judgement, and this has always involved learning under the tutelage of an experienced engineer, not a more complexified, unreadable, uninterpretable, gooder code edition at an exorbitant price. When I read bldg. codes these days, I don’t have enough fingers, triangles and scales to mark the pages as I refer back, and back further, to other subsections, other ref. documents, etc. You soon get lost in the minutia and forget what you are really designing. We are so busy worrying that we may have missed a small subsection item back on page 4728, and that we might get sued for this, that we can’t see that this is just a crappy detail which won’t work even if designed to the nat’s a$$.

We do need good people, practical, practicing engineers on these committees, or this whole code thing will continue going down the tubes. The academic types will keep turning out this trivial research, just as they are turning out unqualified young graduates, but otherwise, 85% of this research does not need to find its way into a new printing of the codes next week. Good engineers used to read the tech. journals and bring some of the research into their designs once it had been peer reviewed and discussed, and that didn’t need a new $300 per copy printing of the codes. If you want to do something constructive, go to you AHJ or your State legislators and explain to them that they are not getting better infrastructure by adopting the next edition of the IBC. Let us learn to use the one we now have efficiently and effectively. You want us stamping these designs, so let us make wise use of materials and current knowledge without hampering us with a newer, even better?, bunch of indecipherable b.s. Let the ICC sit with unpurchased printings of the next couple editions of their codes and maybe they will slow down a bit, and get a bit more practical.

For all the intricate numbers the codes and FEA allow me to run, when all’s said and done, I can’t find a W24x134.35 beam. So, I’ll go to a W24x145, and now if I rerun my design I can space the beans at 20.833' instead of 20'. Then when I finally get the mill certs on those beams, I can redesign again, and space the beams at 21.002'. Oh, gosh, you mean I gotta move the columns and the footings too.

 

[Archie264]

...R-sub-bvq should be multiplied by 1.57 or 1.59 because it is a Thursday and it’s raining...

...I can’t find a W24x134.35 beam...

 

[woodman88]

briancpotter -
You are missing my point. What I was addressing is the fact that they moved the 1.6 factor to the other side by using a 1/1.6 equivalent factor. Than upped the wind charts by 1.6. That is 1.6(90sq) = 114sq for the new V = 115.
Than got rid of the important factor by multiplying them to the wind chart values and created two other charts. So that we now three charts to look at inplace of the one chart that got multiplied by a factor.
When there is no reason (except to make changes so it appears that they are doing something) to move the factor or to make three wind charts just to remove the wind important factor. They could of merely adjusted the existing factors for the same results.
The same thing goes for the ASCE.

Garth Dreger PE - AZ Phoenix area
As EOR's we should take the responsibility to design our structures to support the components we allow in our design per that industry standards.

 

[frv]

woodman88,

If I recall, the change does reflect more accuracy in high-wind areas (hurricane-prone areas). But yes, the net result for those of us who practice anywhere other than the coast is that we now have added complexity for a net change of nearly nothing.

 

[woodman88]

frv -

I am sorry but more accuracy from a map of the USA printed on two 8.5” x 11” pages is a joke.
They could easily have added blowups of critical areas, like what was done for the seismic maps.
If they did need to make changes in special areas for the difference important factors, that could have been added also.
But what they did is an insult to engineers IMHO.

Garth Dreger PE - AZ Phoenix area
As EOR's we should take the responsibility to design our structures to support the components we allow in our design per that industry standards.

 

[SAIL3]

I really really get ticked-off and frustrated anytime I have to plough thru these recent codes to the point that I use them less and less for all the reasons mentioned sofar and many more I could add.
I do not consider myself the sharpest tool in the shed, but , with over 35 yrs of real engr experience and two master"s degrees, I, all of a sudden, could not become that stupid that much of these recent codes make absolutely no logical sense to me...they have become more of a book-keeping exercise than a technical document, more of a hunt-and-peck endevour than a sound engineering presentation....the amount of time I have wasted and the time and cost to all the states, cities etc, implementing the newest version of these documents must run into the millions at a time when these entities are struggling to provide basic services to their population with all the cuts in budgets......but, complaining amongst ouselves will have no influence or change the course of events in the future...until there is a real monetary cost to the members of these commitees and the issueing organization for the amount of misdirected and unnecessary effort imposed on the practicing engineers and municipalities that have to implent them, then, I am afraid it is only going to get worse.....

 

[hokie66]

These building regulation codes are becoming more and more like the Tax Code.

 

[briancpotter]

woodman88-

The increased accuracy has nothing to due with the size of the maps. It's because of the way occupancy (now risk) category works. The loads to be designed for are based on return period of a hurricane - the safer a building needs to be, the more certain you need to be that the loading won't be exceeded. Thus the hurricane return period for a normal office building is only 50 years, where for a power plant it's 1700 years. This is because a 0.1% (or whatever) chance of a hurricane destroying a building is an acceptable risk for a house, but not a power plant.

As Sandy just showed us, hurricanes have the possibility of hitting a very broad swath of the country. The longer your return period, the more places become "hurricane zones" and need to be designed for hurricane winds. Thus you can easily have two buildings in the exact same location where one needs to be designed for hurricane loads, and the other doesn't. It doesn't just affect a few special areas, but anywhere remotely close to the Atlantic/Gulf coast. The previous contours + importance factors didn't properly reflect this, and gave incorrect loads for high-occupancy category buildings, the exact buildings where getting the loads right is most important. That's why new wind contours were needed.

It's unfortunate that it requires a (slightly) more complex calculation, but it's not an unimportant change.

Brian C Potter, PE

http://simplesupports.wordpress.com

 

[briancpotter]

My mistake, it looks like the primary cases affected are low-occupancy buildings. From the commentary:

"Multiple maps remove inconsistencies in the use
of importance factors that actually should vary
with location and between hurricane-prone and
nonhurricane-prone regions for Risk Category I
structures and acknowledge that the demarcation
between hurricane and nonhurricane winds change
with the recurrence interval."

Brian C Potter, PE

http://simplesupports.wordpress.com