vmirat, for this discussion, your quote by Doug Loos should be extended thus: “....have no reason to suspect the extent of our ignorance, so then we apply load and resistance factors to prove that we are.” Anyone here ever heard of the KISS principal (keep it simple stupid)? I still have a couple slide rules which, if still used, and combined with some good experience and judgement could produce very good structures. The first conc. design code I used measured 6"x9"x3/8" and my buildings are still standing and functioning just fine. I like my hand held calculator and run my calcs. to enough precision so that my geometry or forces do self check at a joint. I do not think that this precision amounts to a more accurate or better design, I’m just assuring myself that I haven’t lost 10° or 5k at a connection. I even use a computer, but try not to let it do my thinking for me or let it cloud my judgement when my experience suggests there may be a problem. Let’s not complicate BigH’s life by making him factor things up and/or down; I go to him for his knowledge and experience with soils and local geology when my foot print in the footing excavation or my thumb print in the clay isn’t enough for me to be comfortable designing around them.
We certainly should understand the probabilistic nature of our work; but let’s not let code writing and re-writing and the science and math behind that, turn into the be-all and end-all that they are becoming. All the research and testing is wonderful because we end up smarter about what we are doing for having followed this research. But, introducing much of this into new versions of the codes every few years, when they all refer to each other, but none of them are in sync. is just making our life tougher, not really producing better structures. I can hardly afford to keep up with the latest codes the way they are churning them out, and I suspect that many of us don’t really learn their new intricacies before they are replaced by a new ed. Then we need the 2009 version of one code, the 2006 version of a code it refers to, etc. etc., and finally a ASTM standard that we haven’t purchased yet, just to get a partial picture of what we should do and think to comply with the latest code. I always thought the commentaries were as important as the exact code wording or numbers, because I might come away with a better understanding of what the numbers meant and why I was doing what I was doing. For all the complexity we have added to the design process, we are not producing a sufficiently superior end result or saving a heck of a lot of material. Again, our improved knowledge of design, materials, etc. are important for our judgement; and our better understanding of seismic and wind loading, etc. are important enough to be included in the codes once they are well enough understood; but inclusion of some of the other miscellanea just keeps the code publishers in business and taking our money. A good code would incorporate most of this new knowledge into a few ‘thought adjustment factors’ which, when applied, meant that I could design a little closed to ultimate strength here, or I better leave a little more margin of safety there, judgement and experience again.
I dare-say that most of the structure problems that I investigate have little to do with not following the latest code to a tee. But, they do show plenty of lack of understanding of good details, how structures or soils really work, or just plain lack of good engineering common sense. The code doesn’t cover that; did your education, did your mentor? The guy who can run the computer fastest should be relegated to that function alone, until he gains enough experience to know when his modeling is wrong and the guy who is very good with CAD shouldn’t be left to check the details. I submit that we might save more by paying attention to, how a member is most easily fabricated and erected if using steel or how easily the member is formed and the reinf’g. stl. assembled and installed if using conc., than most of the new code machinations ever will.
We might be smart to go back to the days when the codes didn’t cover every possibility, every new hypothesis or idea, and all the very latest misc. new knowledge. Then critically important findings can be covered by an addendum until the next edition ten years hence. $50k of experience will trump $100k of new codes and software almost every time, and I don’t care whether you use a factor of 1.2 or 1.6 on that fact. BigH and I could probably work well together. That’s my introductory rant.