Structures: Or Why Things Don't Fall Down (Da Capo Paperback)

by J.E. Gordon

the Poisson’s ratio – and hence the lateral contraction

Whether it stays there depends upon problems of control and stability and structural strength which are conceptually difficult.

Not only our legs, but virtually all bones, are surprisingly weak in torsion.

Beyond about 20 per cent tensile strain, all chemical bonds become weaker and will eventually come unstuck.

buildings are essentially compression structures

wood is weaker in compression than in tension

In engineering structures, panels and shells are very often stiffened by means of ribs or stringers which are glued or riveted or welded to the plating,

support any given load, a long strut has to be made very much thicker, and therefore heavier, than a short one.

As a matter of fact the square-cube law seems to apply with full force only to the lintels of Greek temples (which are made from weak, heavy stone), icebergs and icefloes (which are made from weak, heavy ice) and things like jellies and blancmanges.

All structures will be broken or destroyed in the end -just as all people will die in the end.

Sir Alfred Pugsley points out in his book The Safety of Structures,

Jacques Heyman has laid down the principle that ‘If a structure will stand for five minutes, it will stand for five hundred years.’ For masonry structures built upon rock this is, broadly speaking, true.

with modern knowledge and methods of treatment, it should be possible to get a practically indefinite life from almost any kind of wood.

One of the most insidious causes of loss of strength in a structure is ‘fatigue’: that is to say, the cumulative effect of fluctuating loads.

Aluminium alloys do not have a definite fatigue limit but tend to tail off, something after the fashion of Figure 4. This makes them more dangerous to use and accounts for some apparently old-fashioned prejudices in favour of steel for use in machinery and other structures.

As Pugsley points out in The Safety of Structures, it is inherently impossible to make regulations about the strength of structures which are proof against both fools and knaves without preventing, or at best handicapping, development and innovation.

These people treated their engines and boilers with a degree of ignorance and carelessness which almost passes belief.

error shades off into what it is now very unpopular to call ‘sin’.

I have been forced to the conclusion that very few accidents just ‘happen’ in a morally neutral way. Nine out of ten accidents are caused, not by more or less abstruse technical effects, but by old-fashioned human sin – often verging on plain wickedness.

do not mean the more gilded and juicy sins like deliberate murder, large-scale fraud or Sex. It is squalid sins like carelessness, idleness, won’t-learn-and-don’t-need-to-ask, you-can’t-tell-me-anything-about-my-job, pride, jealousy and greed that kill people.

‘ Why don’t you have Mr Smith in your Cabinet, Mr President?’ ‘I don’t like his face.’ ‘But the poor man can’t help his face!’ ‘Anybody over forty can help their face.’

Each age thinks itself in possession of the true and only view possible for sensible man.

we are duly horrified that our ancestors were prepared to tolerate physical poverty and to inflict physical pain. But these same ancestors would be just as horrified that we should suffer many millions of people to experience every day the beastliness of London or New York; and that those who work in our Dark Satanic Mills should have to be well paid to put up with noise and ugliness which are largely unnecessary.

We happen to be a society which is unable to make attractive beer-cans. Indeed we are, I fear, an age rather noticeably lacking in inherent grace and charm.

I believe that very few artefacts are intrinsically ugly or beautiful simply because of their function*; they are rather mirrors to an age, to a set of values.

Engineers have to deal, not only with people and all their quirks and weaknesses, but also with physical facts.

It may be the engineer’s job to point out that the emperor has no clothes on, but however embarrassing this may be, we clearly need more, not less, of this kind of realism.

as modern technology gets more and more functional, we can less and less bear to look at it.

the pursuit of the last ounce of performance results in a boring appearance, as one can see in modern yachts.

science has subtly warped our system of values by teaching us to judge on grounds which are excessively functional.

ugly ship is no more attractive than an ugly woman -however fast she may be’.

fully to appreciate formal achievement it is necessary to have some knowledge of the rules.

The roofs of classical buildings, as we have seen, can only be described as a structural mess. But there is nothing wrong with most of these buildings aesthetically.

The real heroes of Gothic cathedrals seem to be the statues, whose weight, perched on pinnacles and flying buttresses, keeps the thrust lines stable

There are those who moan about ‘meaningless ornament’; but the phrase is surely an oxymoron, for no ornament can be ‘meaningless’

Is it not fair to ask the technologist, not only to provide artefacts which work, but also to provide beauty, even in the common street, and, above all, to provide fun! Otherwise technology will die of boredom.

R. J. Roark’s Formulas for Stress and Strain (McGraw-Hill). These formulae can be used by people like you and me equipped with little more than common sense,

Remember, remember, remember, that these formulae take no account of stress concentrations or other special local conditions.

Formal engineering drawings are very necessary when components have to be made by the usual industrial procedures, but they are troublesome to make and may not be needed for simple jobs or amateur work.

It is confidence that causes accidents and worry which prevents them.

do not be ashamed to play with Meccano, or even with old-fashioned building blocks. These things, incidentally, are much more instructive than the modern plastic toys which clip together in various ingenious ways.

Philosophy of Structures, by E. Torroja (translated from the Spanish). University of California Press, 1962.