Structure Mag......Code Article
Structure Mag......Code Article
(OP)
"Experienced engineers (5 to 40+ years) produced design wind forces that varied from 3.9 kips to 24.2 kips with a standard deviation of 42% in the results."
This agrees with what I have been figuring for some time now based on seeing other engineers work. I know I have unintentially missed things as well. All the west coast engineers seem to be currently having a hard time adjusting to ASCE wind, but seismic is even worse to me-especially getting all the special detailing right.
"Why have we as practicing engineers allowed the codes to become so complex? I propose the single biggest answer is apathy"
I agree with this one too, and apathy seems to fit our fees as well. But I am also guilty on the code part because I have never been to a committee meeting on anything and argued for simplification. A good one would be, why now does it have to take 4 hours to design a couple of anchor bolts by hand?
htt p://www.st ructuremag .org/Archi ves/2007-1 2/D-Editor ial-Nuttal -Dec07.pdf
This agrees with what I have been figuring for some time now based on seeing other engineers work. I know I have unintentially missed things as well. All the west coast engineers seem to be currently having a hard time adjusting to ASCE wind, but seismic is even worse to me-especially getting all the special detailing right.
"Why have we as practicing engineers allowed the codes to become so complex? I propose the single biggest answer is apathy"
I agree with this one too, and apathy seems to fit our fees as well. But I am also guilty on the code part because I have never been to a committee meeting on anything and argued for simplification. A good one would be, why now does it have to take 4 hours to design a couple of anchor bolts by hand?
htt






RE: Structure Mag......Code Article
It seems every year specs get thicker and thicker or more and more complex. AASHTO is the worst. I think the latest volume may excced the allowable floor loading for my office. AISC has not gotten that much thicker, but has required more sophisticated analysis. I think that software companies and acdemics have convinced code writers to require very sophisticated models but the computational means are there. Although this may sound good in theory - if we can make more exact models, why not?, We now have codes that require the use of programs that we can not touch by hand. More and more engineers absolutely need a computer to solve problems. Ask for slope deeflection or moment distribution by hand and they look at you blankly.
Now even the wind load codes are so complex, they aparently can not be solved by hand. There are a lot of structures designed by hand to simple understandable models that have stood the test of time. Not that every model needs to be solved by hand, but such models shoud not be eliminated as they reinforce our understanding of the actual load and response. I saw the article - it is really good. the entire magizine is quite good.
RE: Structure Mag......Code Article
I took some measurements:
1953 AASHTO 6th Edition 6"x9"x 3/4" 40.5 In^3
1973 AASHTO 11th Edition 6"x9"x 1 1/8" 60.75 In^3
1996 AASHTO 16th Edition 8 1/2"x11"x2 1/2" 233.75 In^3
2004 AASHTO LRFD 3rd Edition 8 1/2" x 11" x 3 3/4" + 2 1/2 " of interim specs 584.38 In^3
Perhaps the paper companies are in cahoots with the software writers and academics.
RE: Structure Mag......Code Article
Hg
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RE: Structure Mag......Code Article
We need to rise up, in arms if necessary!
It is just impossible to do things by hand and be profitable. I am a relatively young engineer, 35. I prefer to do things by hand when I can just to understand what I am doing. But, to turn a profit, it is really difficult these days to do that. I barely remember how to do indeterminate structures by hand. Just designing a simple shear connection by hand would take too long with these budgets. The young engineers now are just computer jockies. That's a shame. First AutoCAD released the young engineers from the board to our detriment. Now the computer is releasing the young engineer from theory and the design itself. We just interpret results and draw details. For bridge engineers it is even worse. They don't even draw details. I did that for 3 years. I had to get back into buildings because i didn't feel like an engineer anymore.
The codes have increased our effort while our fees are decreasing or are stagnant. There is a shortage of engineers yet our fees don't obey the law of supply and demand. The architects and state DOT's have us by the you know whats. With the architects, things might change with the new generation (my generation) but I am not too optimistic. The state DOT's will never change.
One reason the codes are more complex is that professors need to justify their research projects. They want to see their name published and they lobby the code committees. Many of the code equations are based on one research project. That is ridiculous. We need to infiltrate the universities and make changes. I'll never let my child be an engineer. I love the work but why take on this much stress and responsibility when they can be a dentist or lawyer and make 10 times as much, literally.
RE: Structure Mag......Code Article
I do this frequently. I get my way a lot of the time.
Code writing is a "do-ocracy". If you're willing to do it, you stand a chance of getting what you want. Otherwise, put up with it. Bitching about it in a forum, saying, "Oh me, oh my, surely something must be done! Those eevul perfessers! Those scurvy knaves at the DOT!" accomplishes nothing.
Hg
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RE: Structure Mag......Code Article
The fault lies with lazy, ignorant, arrogant, naive young people and complainy, lazy, arrogant old people. Young engineers should have the brass to learn something for themselves and older engineers should have the courtesy and foresight to point them in the right direction. Otherwise all you have is young pups listening to the Alzheimer's unit complain about new-fangled techonology and talk about going uphill both ways to school. That's not productive at all.
There seems to be a lot of that lately among the older generation in the trade publications. Too many gray and blue hairs crying about the younger generation and not enough turning that criticism inward.
Note that this is not every young person, and not every older person. that seems to get left out frequently. Let's not get into stereotypes if possible. I exaggrerated to make a point only.
How many here plan to participate in the trial design problem mentioned in the article?
RE: Structure Mag......Code Article
RE: Structure Mag......Code Article
I don't have the time to run committees. I can complain anytime I like to whomever I like. Everytime I go to a seminar that is hosted by a committee member, I complain and make my concerns known. I'm glad you have accomplished things with your letter writing. I never have. I've sat on three DOT committees in grad school. Nothing get accomplished except by those with an agenda. The committees are usually driven by a couple of stubborn people that don't back down and they usually get their way. I can't bear the cross for this profession in the fight to make it better. It is broken beyond repair. I will just make sure my children don't make the same mistake I did. Do what you love. That is what they tell you. Only when you're older do you realize that work is only work and that money DOES make life a lot easier and more enjoyable. Thankfully, I married a dentist.
RE: Structure Mag......Code Article
These two articles are pretty much in direct opposition. ACI Appendix D is one of the most complex codes I've seen. I thought it was pretty funny that both articles show up in the same edition.
RE: Structure Mag......Code Article
RE: Structure Mag......Code Article
Way to go, love it. Unfortunately I didn't marry a dentist. Anybody looked at the EuroCodes and related info lately? Wow's all I can say. It's a wonder anything is standing!
RE: Structure Mag......Code Article
RE: Structure Mag......Code Article
RE: Structure Mag......Code Article
Hg
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RE: Structure Mag......Code Article
Same thread, scares me when I see myself in the same discussion from another thread because it often depends on the day I've had and the # of beers I've had when I get home before I open up eng-tips.com to see whats up in the world of structural engineering. Yes little has changed vmirat since your post, your gracious ending to it was well appreciated. It allowed me to could go to bed and look forward to the next day. It's not all crap and crazy, some interesting things going on. Just wish I had more time and money. Applied Physics and Mechanics, very cool!
RE: Structure Mag......Code Article
Remember IBC was heavily criticized for the increase in lap lengths for masonry construction. Is it any wonder that the lap lengths are long enough to justify mechanical splices and that fact that over a third of the committee that approved the changes was from the mechanical splice industry?
I served on a small ACI 318 committee. I was amazed at the number of proposals I received from the construction industry to push for their products to be included or ban their competition. The typically committee consists of 1/3 Professional Engineer that practice engineering, 1/3 Professors and 1/3 from the industry. Since they have a hard time getting real Engineers to sit on the committees they are often replaced with professors that are PE’s or industry salespersons that are PE’s. You will get a lot of I’ll vote for your item if you vote for mine.
The changes would not bother me if we had failures or faulty designs. Have you seen a correctly engineered and constructed building fail under code loads? The majority of failures I have investigated are the results of one of the following.
1) Water
2) Lack on maintenance or age of building
3) Bad construction
4) Extreme loading conditions well beyond design values.
My old steel professor explained it best to me many years ago.
We had researched everything we could with ASD and had nothing left to research. So the best thing to do is come up with another method and research it all again. Hence you now have LRFD, Laboratory Research Funded for Decades.
Look at the new AASHTO code, over 1500 pages. It doubled in size when it went to LRFD. Has that much really changed?
ASCE, which many of us are members of and pay them over $200 a year. They are now one of the largest providers of Continuing Education, their committee members make thousands educating us on why the SL or WL have changed yet the answer remain the same. And ASCE pushed to make CE required for professional engineers, do you wonder why? Now they are pushing to make a M.S. degree the first requirement for obtaining your P.E. license. Why not, most ASCE committee members are professors and they will see their Grad. school enrollment sky rocket. I’m glad retirement is around the corner, maybe I will teach in my old age. They could probably use a Professor for all the new grad students.
RE: Structure Mag......Code Article
RE: Structure Mag......Code Article
RE: Structure Mag......Code Article
RE: Structure Mag......Code Article
Did you hear that ASCE 7 is now making a new simplified simplified method of calculating wind. I thought the simplified method was simple and supposed to be faster. I did a problem with the simplified method and the analytical method. I arrived within 0.5% the same load. Both methods took me the same amount of time to calculate both. I hope the new simplified simplified method is truly simplified.
I am going to write a paper on ACI Appendix D in one of the journals soon. I have been studying the history and method of Appendix D for some time now. I have stumped people on the committee with questions. It is time to expose it with hardcore numbers. Appendix D is driven by one person. Yes that's right, one person. I am going to contact this person and set things straight.
I am also going to contact my old professors whom I stil have relations. I am also going to contact local professors at the universities to try to talk some sense to them. It might be the only way. I also encourage all of you; when you attend seminars, gripe, gripe and gripe. Make them feel uncomfortable. It may be the only way to get our points across.
The wind code is hopeless.
The seismic worse.
Our computer models are not accurate enough to model buildings for the precision calculations that are required.
"Structual engineering is the art of molding material we do not wholly understand into shapes we cannot precisely analyze to withstand forces we cannot totally assess; in such a way that others have no reason to suspect the extent of our ignorance."
RE: Structure Mag......Code Article
RE: Structure Mag......Code Article
Regional building departments amend/append model building codes, either because of their local area conditions or because they disagree with the code requirements. Our building department didn't adopt the 2000 IBC/IRC because it was a total mess. They finally did adopt the 2003 code (with lots of changes of their own) but still use the UPC for plumbing.
I would like to think that the code writers have an honest interest in protecting the public. Seismic is a good example. However, I would rather people spend a little more on construction of a conservatively designed structure than save half a penny by calculating down to the nth degree the capacity of a structure whose variability in actual capacity exceeds the level of detail you figured it to handle.
RE: Structure Mag......Code Article
For buildings lower than 15 m / 50 ft:
Add a constant pressure of 500 N/m2 to all outer surfaces of the building (walls & roof); check that bending won't break the walls or open the roof.
Then remove the pressure from one side of the building and check that the walls perpendicular to it won't fall down due to shear. Repeat this procedure for all walls.
;)
RE: Structure Mag......Code Article
Wall: 10 psf total (minimum)
Parapet: 17.5 psf and -11.6 psf
RE: Structure Mag......Code Article
A lot of you fellows have a very distorted view of a professor's life and motivations! That's ok--we all see the world through our own little glasses. I'm one of the only people I know who has two sets of glasses, LOLOL.
For one thing, they don't serve on committees because they have more time than designers. After getting a closer look, I'm not sure good professors have more time at all. Deadbeat ones have more time, but these guys aren't pushing or creating anything that will ever affect a designer.
Good professors are VERY interested in what they're doing, so pitch in craploads of their "spare" time--it's more like a hobby than a job. It also has little to do with tenure in most cases.
I do not believe that any committee seeks more professors. I dare say that any PE or SE with a decent resume and >=10 years of experience can get on a committee.
In my experience, the truth is that most designers want to put in a day's work, go home at 5-6pm and spend the evening and weekends with family (noble goals--no argument there).
To a person, the designers I know say they don't have time for committee work. BOLOGNA!! They have the time, but choose to do other things with it. If they don't want to spend a few weekends and evenings per year volunteering time for committee work, then they don't have much of a leg to stand on while complaining, IMO.
It's about like someone complaining about politics, but not voting.
RE: Structure Mag......Code Article
I only had 7 years of experience, a very nice resume, a MS, and a SE license and that was plenty enough to get me on a very non-trivial committee. It took a couple of years to learn the ropes, but I've even been able to have an impact.
Imagine the impact of a >20 year guy doing the same thing!
This stuff just ain't that hard.
RE: Structure Mag......Code Article
RE: Structure Mag......Code Article
I agree that some committees seem non-responsive at times. I've sent good questions to ASCE 7 and IBC-supposed-gurus and received nothing but crickets.
FWIW, our committee spends a substantial chunk of meetings on comments, mostly from folks from outside the committee. Some of these go somewhere and some don't for various reasons. The ones that go nowhere usually have some other consequence that the author didn't think of.
At the end of each discussion, someone agrees to get in touch with the author and let him know what happened and why. Perhaps this is forgotten at times, but it is supposed to happen.
RE: Structure Mag......Code Article
Granted, the wind load provisions are unnecessarily complex, but (I'm going to risk sounding arrogant. Really, I'm not.) how could ANY engineer worth his salt, with >5 years of experience sit down in front of that problem and miss it by a wide margin?
I mean, come on, it is a box, without ANY of the issues that actually are confusing (parapets, penthouses, canopies, partially open, etc.). I'd bet a fair sum that I would come up with the right (or otherwise easily defensible) answer to that and that every other decent engineer with >1 year of experience in my last office would.
The article didn't say either way, but was there a time limit placed on the problem? If someone was given a tight time limit to solve it, then it's understandable.
And I meander further: I'd like to know how much of this has to do with widespread use of automated design software. I dare say that it plays a HUGE part, allowing people who don't study to still design buildings. Remove the need to study and many won't. Our old office hired one SE with 10 years of experience a few years ago who had been using RAM for several years. He literally could not calculate wind or seismic loads manually. We calculated this stuff manually at times, so everybody had to get good at it.
Sorry. I really don't want to come off as arrogant, but something besides code complexity is wrong if THAT many >5 year people couldn't figure it out.
I vote for widespread use of automated software.
RE: Structure Mag......Code Article
271828 (Structural)sounds a little defensive. The point of the thread is -- Codes are getting Complex --
So if the codes are getting complex, what is the downside? The consensus is running that there is a lot of work being required. And any engineer, worth his salt, knows that complexity and more work equate to more sources of error.
For a moment of reality, let's not forget the first rule of structural engineering:
------ When in doubt, make it stout. ---------
And if anyone wants to debate that rule, be sure and include the cost of only the structure, versus the whole project.
3 cheers to -- haynewp (Structural)-- for starting this discussion.
And 3 cheers to -- BRGENG (Structural) -- for an excellent summary.
Now, let's come back to the original (understood) question. What should we do about getting the codes back to a more simple set of rules?
RE: Structure Mag......Code Article
However, I suggest an alternate solution that can involve everyone/anyone, since we ALL can't be on a committee, especially ones like those at ASCE. We should have a third party union that can speak for us proletariat masses with those organizations that are making the rules. Hey, maybe Eng-Tips will act as our advocate!
RE: Structure Mag......Code Article
RE: Structure Mag......Code Article
Everyone on those committees is a volunteer.
And what professors need to do for "publish or perish" is PUBLISH--meaning issue a research report. A CV lists publications. It doesn't list code provisions. Most research reports that *could* result in code changes never get implemented. Why? Because the professor has delivered their deliverable and if they're not on the relevant committee, then it's up to other people to get it into the code. They lobby because they think they have the right answer. They're not lobbying because they think they'll get more funding; more funding comes from NEW questions, not implementing the old ones.
Hg
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RE: Structure Mag......Code Article
RE: Structure Mag......Code Article
And the thing is, even if the more extensive code provisions result in better design practices, which not many of us seem to think is the case; does this improve the resulting structures? I think not.
RE: Structure Mag......Code Article
RE: Structure Mag......Code Article
BRGENG, if you find you need to extend embedment depth "well beyond the frost depth" maybe you are doing something wrong.
RE: Structure Mag......Code Article
RE: Structure Mag......Code Article
Can you give the details of a specific ACI App. D result that was unreasonably severe?
I have not done an exhaustive study of this Appendix, so might not have run into any really stupid answers.
RE: Structure Mag......Code Article
RE: Structure Mag......Code Article
As to where you can get anchor bolts deeper then the frost depth. Braced frames along the hurricane costs of the southwest. Many geotech only have a frost depth of 12” or 18”. A project we did in Myrtle Beach, SC, national proto type for a major pharmacy chain. They use slab on grade, steel frames with a braced bay for lateral forces. Combine the hurricane wind loads on the braced frames and you can easily get anchor bolt lengths greater then frost depth.
RE: Structure Mag......Code Article
As for the example of BFs along the southeast coastline, that's too non-specific to be a good argument against App. D, in my opinion. Do you have a specific uplift force and required anchor rod embedment that you've found unreasonable compared to pre-App. D requirements?
LOL, I haven't studied App. D enough to know, but it sounds like the concrete equivalent to the AISC stability bracing stuff: According to the AISC stability bracing provisions, all metal building rigid frames should've collapsed by now!
RE: Structure Mag......Code Article
thread507-203057: ACI 318-08 coming
RE: Structure Mag......Code Article
RE: Structure Mag......Code Article
I like the appendix for Strut and Tie in ACI.
The real Question.
Who said that we have to adpot the new codes.
In Chicago they've been using ACI 318-83 through all the
new codes. Maybe instead of fighting the code writers.
We just convince our local politicians to not adopt the newer codes. (Easier than go to a committee meeting if you ask me)
RE: Structure Mag......Code Article
Personally I don’t agree with this at all, in many rural areas the elected officials deciding the code have no idea what they are doing.
Here is a quick question to ask yourself. If you are designing a building in an area that dose not have a building code, what building code do you use? Would it be the 93 BOCA or maybe the 97 UBC or do you use the most recent recognize code the 2006 IBC? I always chose to use the latest code, currently the 2006 IBC unless the State the project is in has a different code adopted. This is also why local officials will almost always adopt the latest (but not greatest) code.