To FRV:
This is in response to your more recent posts.
Concerning my "verbosity," the rule when trying to lead someone to a truth that lies off the beaten path is this:
"First you tell 'em what you're gonna tell 'em. Then you tell 'em. Then you tell 'em what you done told 'em."
Most of the reasons for that procedure are pretty obvious, and apply to everyone: new material can be confusing; repetition aids memory; time is required for thought; etc.
In our case, however, there is an additional problem: I'm old, and you are young. In fact, unless I miss my guess, I've been retired longer than you have been alive.
That is a problem because young adults have just recently escaped from parental control. For close to 20 years, they were subject to being told what was true and false, criticized when their behavior or their opinions did not conform to expectations, and, whether they admitted it to themselves or not, they resented the hell out of the adults who so cavalierly ordered them around.
The roots of this problem trace back to the fact that the vast majority of people enjoy having the power to order other people around, and, in particular, they trace back to the fact that vast numbers of parents are obsessed with forcing their opinions on their children. Since we have a government that has the power to make law, parents have exerted continuous political pressure since the founding of the U.S. in favor of more and more parental control. Result: with the passage of time the age at which a person was legally declared to be an adult--the age at which he became exempt from parental control--has risen. Thus the further back you go in time, the lower the age at which a person reached adulthood. While the age of legal adulthood has varied from state to state, one does not have to go back very far to find states where a person could leave home, get a job, get married, sign binding contracts, etc., at puberty. My paternal grandfather, for example, left home in 1886 at the age of 13 because he couldn't get along with his stepmother. He got a job as a physician's assistant, learned the medical profession via on-the-job training, and went into private practice when he was 20. No college education was required at that time, and he had none, but he became an exceptional physician nonetheless.
The point is this: today's young adults carry a lot more resentment towards their elders than prior generations did, because they have more reason for resentment. They have been ordered around longer, instructed longer, criticized longer, and pressured to conform longer, so they carry far more hostility towards their elders than previous generations did. Result: they are inclined to embrace movements and ideologies that differ from what was done in the past, precisely because they are different. This is, of course, wrong: decisions about what to reject or believe should be based on reason, not resentment.
Nevertheless, I understand those attitudes and I sympathize. Furthermore, I'm not in a position to force you to accept anything I say, and wouldn't do it even if I could. I'm not authoritarian or controlling in the slightest. You won't hear me saying "No one knows wood as good," or anything like that. Instead, I'll give you my reasons when you challenge something I say, and it won't bother me in the slightest if you are not persuaded by my arguments. This is, after all, a discussion group. When disagreements arise, reasons are the only thing that matters. Neither age, experience, IQ, school of matriculation, number of degrees, certification, number of books or papers authored, nor any other characteristic matters. In the final analysis, when the chips are down, the only qualification anyone has for holding an opinion are the reasons upon which he bases that opinion, and I would be the last person in the world to deny that.
So relax. I'm not trying to pressure you into anything. You are free to take whatever you wish from my musings, or to take nothing at all, if that is your inclination.
Concerning my "cynicism" about how the members of regulatory bodies are chosen and what their actual purposes are (as opposed to their stated purposes), I would note that in a free market economy, property rights would be sacrosanct. The building trades would be totally unregulated--laissez faire, as the French used to say. Under those circumstances builders who cut corners to save money and threw up nice looking crap that fell apart in a few years would not have the defense that their structures were "up to code." Moreover, the builder would not have the option of scapegoating the engineer of record in cases where the plaintiff's lawyer argued that special circumstances applied, that in those circumstances the structure should have been stronger than the code required, and that the engineer, unless he was incompetent, "knew or should have known" that to be the case. (If there is no "code" that structures need to be "up to," then it is impossible to turn structural engineers into mindless robots whose sole focus is on ensuring that their designs are "up to code.") Instead, under laissez faire, it would be argued in court that standard conditions are assumed, that there is an implicit warranty of serviceability of the structure to its intended purpose unless the builder explicitly informs the buyer to the contrary. Result: the first such failure would result in the builder being liable for damages, which would be paid by his insurance company. Afterwards, with such a failure on the books, (a) the builder's insurance rates would become prohibitive, forcing him to stand behind his work himself, and (b) subsequent failures on his part related to cutting corners on his designs while still not informing his customers that he was explicitly disavowing any warranty of serviceability--that the structure was being sold "as is"--would result in findings of fraud, and he would face criminal prosecution.
What this means is that fraud would not be a viable business strategy in a laissez faire system.
What "regulatory bodies" do is clear a path through the economic system for sociopathic "businessmen" who intend to "succeed" by means of fraud.
Since that is the effect of building codes, is it not reasonable to consider the possibility that it is also their purpose? Should we not ask ourselves whether it is possible that wealthy people who intend to become even more wealthy by means of fraud might influence the political process in ways that would bring about the creation of regulatory bodies? Could they, perhaps, fund the campaigns of politicians whom they know will comply with their wishes? Could they, perhaps, fund the research of professors who argue that regulation is needed? Could they, perhaps, advertise only in newspapers that support their goals? Could they, perhaps, buy newspapers and employ "journalists" who are inclined to support their goals or whom they can bend to their purposes? And, once regulatory bodies exist, could they not influence how the members are chosen? Could they not make potential members whom they cannot influence appear to be "controversial" by unleashing their kept "experts" and journalistic shills upon them?
And if regulatory committees could be created and controlled by such methods, are there not people who would be willing to employ those methods? Is it not possible that there are sociopaths among the wealthy--people who seek to amass more and more wealth, by any means possible, and who are utterly indifferent to the destruction they might cause?
I hope that you are not so young and naive that you cannot see what I am talking about here, because the people I am describing are in the process of destroying our present global civilization as we speak, and are ushering in a new dark age in which you, but not I, will have to live.
Why am I exempt? Because, as I said earlier, I am old. I could die tomorrow, or next week, or next year. I cannot know the day or the hour, but I can know that the day is near because mortality statistics say that it is. Furthermore, that is in no sense a bad thing. I would not want to live in the future that you face and are denying--the future caused by the dark and sinister men who stand behind those whom you describe as "honest, hard-working people whose sole goal is to improve the profession," and "who volunteer their time to make life easier for the rest of us."
Now let me turn to your belief, which you have expressed in various ways, that structural engineering as presently practiced represents a more highly evolved, improved state, when compared to how things were done in the past.
When I read such comments, what immediately comes to mind is lengthy news footage that I watched back in August of 1992, just after Hurricane Andrew moved across south Florida. It was the immediate aftermath of a major disaster, and all the networks were focused on it. The particular footage that stuck in my mind was taken by a helicopter flying low over residential areas, following along the track of the storm. What it showed was very close to total devastation: thousands upon thousands of wooden homes reduced to their component parts. Lumber, wallboard, shingles, shards of broken glass, furniture, automobiles--all the trappings of suburban life--were strewn in a continuous debris field as far as the eye could see, forming a vast ocean of destruction. The helicopter just flew on and on, for perhaps half an hour or more, and the nature of the scene did not change. In particular, and the most unforgettable aspect of it all--the pattern that stunned me and will stick in my mind as long as I live--was simply this: there was a sprinkling of residential wooden homes that were not destroyed. They just stood there like rocks in the sea of destruction, unaffected by the winds of a category 5 hurricane, while all the homes for miles around them had been swept away.
And here's the kicker: every single such home that I saw in live footage that lasted approximately half an hour, were built in the architectural style common roughly a hundred years ago, back when America was still a free country, when restrictions on builders were mostly unheard of, and when such minor restrictions as existed in a few isolated areas were trivial by comparison to the labyrinthine restrictions prevalent today.
That was my "heads up," the tap on the shoulder that came down with such force that it could not be ignored, telling me that regulation of the building trades, which has been sold to the public based on the pretext that it would make them safer and improve the quality of construction, has in fact been a palpable fraud which has accomplished exactly the opposite of what was promised.
In a free market economy, standard conditions are assumed. If you build a house for a customer, there is an implied warranty of serviceability unless you expressly indicate otherwise. It is expected that you have produced a product which will perform its intended function under the conditions in which it is intended to be used, provided only that it is properly maintained. If you do not indicate otherwise, that is the implicit contract which you enter into with your customer. Standard conditions in Florida, in a free society, would require that a new home be able to withstand a category 5 hurricane, because there is a very real prospect that it will experience one during its intended lifetime. If it won't do that, the builder needs to say so, and say it in an open, explicit, and unmistakeable way. You can't hide it in the fine print. You can't say it in a whisper while the customer is distracted. You need to be open and above board in all respects. Otherwise, when the Big Bad Wolf comes and blows the house down, you are going to be liable. You can't say the home you built was "up to code," because in a free society there ain't no steenking code. You can't call a building inspector to testify at your trial because in a free society there ain't no steenking building inspectors. In a free society, you have only one defense if the house you built falls down: you have to be able to demonstrate in court that you explained to the customer prior to the purchase what the maximum stresses were that the structure could withstand and what its expected lifetime would be given proper maintenance, and you then have to demonstrate that when it failed it was either because (a) the maximum stresses had been exceeded, (b) the intended lifetime had been exceeded, or (c) it had not been properly maintained.
That's the way a free society works. In a free society, the economy is not "regulated." That means no path has been cleared through the economic system for "businessmen" who intend to "succeed" by means of fraud. Result: in a free society, businessmen of that sort cannot compete. They are either sent to jail, or else they are sued into impoverishment, and spend their lives working at their actual level of competence (e.g., cleaning other people's toilets), as they deserve.
That is the distinction which explains why the Big Bad Wolf, better known as Hurricane Andrew, turned the "modern" homes in south Florida into a sea of destruction, while leaving hundred year old homes mostly untouched.
Regarding compression perpendicular to the grain, you expressed doubt that it was a failure mode that had safety-related implications, and asked for an example.
First, we need to focus on some basic logic. To that end, imagine that you have a couple of white oak 2x4s, square cut on the ends, roughly 2 feet long. If you pick up one of them in each hand, hold one in a vertical orientation and the other horizontal, and rest the end of the horizontal member on the top of the vertical one with the 3.5 inch sides of both boards facing you, then the area of contact between them is going to be (1.5)(3.5) = 5.25 square inches. In compression perpendicular to the grain the elastic limit of clear wood, white oak in this case, would be 1073 psi, so speaking in terms of pure physics, if these two 2x4s are made of clear wood, with one functioning as a beam and the other as a column, the beam can transfer up to (5.25)(1073) = 5,633 lbs to the column without exceeding the beam's elastic limit.
Note, however, that this is true only because the angle between them is 90 degrees. Moreover, the angle between them will remain 90 degrees only so long as the only force involved is the downward acting force of gravity. As soon as a lateral force enters the equation, the angle at the joint where the beam interfaces the column is going to change, even if the lateral force is very small and the change is very slight. Suppose, for example, that you hold the vertical board with your left hand so that it stands on your kitchen table and push the horizontal member to the left with your right hand, allowing the vertical member to lean to the left. Result: as it leans, an angle will open up between the two boards and the area of contact between them will drop from 5.25 square inches to a very small area, a fraction of a square inch. The "beam," at that point, will be resting on the edge of the "column," and the area of contact between them will be close to zero.
Something similar happens throughout every wooden structure, to every joint between a wooden beam and the column that supports it, when the wind blows: as the structure leans in the downwind direction, however slightly, the areas of contact between the beams and columns try to decrease. However, since they are bearing heavy gravitational loads, what actually happens is that pressure decreases on the lee side of the surface of contact and increases on the windward side. It is only when the lateral force exerted by the wind is extreme that an actual angle will open up between the beam and the column on the lee side of the interface. The effect, however, is the same as if an angle had opened up, because the pressure across the windward side of the interface rises above the value it had when the wind was not blowing, toward the elastic limit of clear wood. Somewhere along the way, if the lateral force keeps rising, each individual beam in the structure will first reach, and then exceed, its own individual elastic limit. Beams the ends of which are flawed, containing knots, pitch pockets, separated grain, etc., will reach their individual elastic limits first, in an order determined by their positions within the structure and the extent to which they, individually, are flawed. But finally even those beams which have ends consisting of clear wood and which are favorably positioned within the structure will reach their elastic limits. At some point in the process, joints between beams and columns are going to begin to give way, and very shortly afterwards the structure is going to come apart. And the failures, in almost every case, are going to be due to the ends of the beams giving way, rather than to failure of the columns. The reason: Newton's third law says that contact forces are always equal and opposite. That means if an upward pressure of 1073 psi is exerted on a beam made of white oak, an equal and opposite downward pressure is exerted on the column that supports it. And since wood is vastly stronger in compression parallel to the grain than it is in compression perpendicular to the grain, it is virtually always going to be the ends of the beams that will give way under heavy lateral loading, thereby allowing the joints between beams and columns to tear apart, and initiating the failure of the structure as a whole. Moreover, none of the widely-used beam-column connectors address this issue in the slightest, and the unconventional ones that do address it use metal corner braces to freeze the joints into a right angle--which means: when lateral loads rise, both the ends of the beams and the tops of the columns will experience rising stresses acting perpendicular to the grain. Result: the problem is not solved; it is merely shifted to a different location.
Bottom line: the only way to address this problem is the way it was addressed a hundred years ago: you need much larger safety factors for compression perpendicular to the grain, and you need to accept the larger columns and the associated rise in costs which such safety factors imply. That's why I said several posts back that the implicit safety factors hidden in the design-value tables for compression perpendicular to the grain are too low--so low, in fact, as to be ridiculous.
That's why Hurricane Andrew disproportionately destroyed the new homes and spared the very old ones.
That's why America was a far safer place when it was a free country with an unregulated economy, operating under the principle of laissez faire, than it is today, with an economy in which "regulation in the public interest" has been used to clear a path, in virtually every area of economic activity, for human predators whose "business plan" is to "succeed" by means of fraud.
That apparently caused confusion before, so let me emphasize that a safety factor is a divisor, not a multiplier. To revisit the example I mentioned in my original post, the white oak design value for compression perpendicular to the grain is 800 psi, while the corresponding measured strength of small clear samples is 1073 psi. That means the measured strength has, in effect, been divided by a safety factor, SF, to produce the design value, as follows:![[bigsmile]](/data/assets/smilies/bigsmile.gif "[bigsmile] [bigsmile]")
I do not think that perpendicular to grain is much of a safety issue, most of the time. I see it as more of an Architectural finish issue, primarily affecting sheetrock and overall appearance.