Measurement system - Metric/Imperial?

[LumpenDoodle2]

In the words of McGonagall-

It must have been an awful sight,
To witness in the dusky moonlight,
While the Storm Fiend did laugh, and angry did bray,
Along the Railway Bridge of the Silv’ry Tay,
Oh! ill-fated Bridge of the Silv’ry Tay,
I must now conclude my lay
By telling the world fearlessly without the least dismay,
That your central girders would not have given way,
At least many sensible men do say,
Had they been supported on each side with buttresses,
At least many sensible men confesses,
For the stronger we our houses do build,
The less chance we have of being killed.

Edited November 1, 2016 by LumpenDoodle2

[TinkerTailor]

17 hours ago, Art said:

Ah yes, but they built the Forth Rail Bridge using Imperial measurements.  Then again, they also built the Tay bridge (prior Forth Rail Bridge) using Imperial Measurements too, and we know how THAT turned out.

Art

Metric/imperial had nothing to do with it.

The problem with the Tay bridge was they left the tape measures in their pockets. The major determining factors of the crash were poor fitting bolt holes, casting shift, poor and lack of machining, and impurities in the materials. The foundry both "burnt in" patches in the cast iron parts but also put putty consisting of beeswax and iron filings under the paint. Many of the columns had porosity and impurities in one side from bad casting practices, poor metal and horizontal casting techniques.  In addition they found nuts that held down the columns that had burrs of .05" on them from the poor face machining which would have equated to 10+ inches of movement at the top of the pole. The cross braces had a design which used slots and gibs to put them under tension, many of which came loose the first year and were tightened up by hammering them in or replacing with bigger gibs. The inspector who "fixed" the braces was a mason with little metal experience. This may have forced the bridge into an incorrect, stressed geometry.

In addition, trains would frequently exceed the 25mph limit in one direction and cause oscillations in the bridge. This could not happen the other way due to slope and curve. Their was inconclusive evidence that the train may have derailed just before the accident and hit the bridge, starting a cascade. There was argument as to whether the oscillation or speed caused it.

It was basically determined that if the bridge had been built to the proper material standards with inspection, and was used in the way designed, It would have stood. It was noted that it was under designed compared to other similar earlier bridges and also noted that it was re-designed on the fly to reduce weight and number of columns cause the bedrock ended up being way deeper. The onus went solely on the designer because he was responsible to sign off on all of the materials as well as the design. As such, even when the suppliers hid flaws from him actively, it was his responsibility.

If they only had used ANY measurement system, those people may not have died.

I often wonder if we really learned from our mistakes? We now have good designs poorly made in China, with the bare minimum quality control (if any) to allow things to work and sell.

That is how we end up with thomas the train wooden toys for toddlers with lead based paint in toysauRus.......infant formula and pet food with melamine in it.  And cell phone batteries bringing down airplanes.

 

Edited November 1, 2016 by TinkerTailor