Engineers really know their stuff

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BadDog
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Re: Engineers really know their stuff

Post by BadDog » Wed Mar 21, 2018 12:44 pm

Ahh. The phrase "resulting in major damage" was talking about a catastrophic failure of the tank damaging the house because a developing leak went undetected, not damage to the septic. Sorry, didn't realize that was ambiguous.

Regarding your damp ground, by your own assertion, you would notice long before that. Particularly if the drain is as I suggested, somewhere that it draining would tend to be noticed.

Boats tend to get regular maintenance because, particularly ocean going, they can be disastrous if they fail, so such systems would hopefully be checked/tested at some interval. Smoke alarms have self test buttons, and chirp to let you know the batteries are low. And they too fail. And so on. Not an indictment that they should therefore be abandoned, just that systems that can fail silently and fail to do their job (at great risk of loss) usually have redundancies and service/test intervals that should be followed. Again, I prefer "bid dumb (cheap, non-moving, limited failure mode) parts" as opposed to complex systems, at least where there is not a darn good reason to go with complexity. So again, pan with drain to obvious place...
Russ
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SteveM
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Re: Engineers really know their stuff

Post by SteveM » Wed Mar 21, 2018 1:08 pm

John Hasler wrote:
Wed Mar 21, 2018 10:33 am
Well, at least he could count.
Yes, and the job got easier and easier because the numbers kept getting smaller.

Steve

tornitore45
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Re: Engineers really know their stuff

Post by tornitore45 » Wed Mar 21, 2018 3:15 pm

The boat was a 1978 model. The ground fault interruptor was invented in...1961. My guess: the engineer who designed the electrical system graduated in 1960.
In 1961 the transistor were just becoming in commercial use their cost was about $2 each in '61 dollars (small signal type).
The famous Sony 7 transistor radio had 3 working transistors and 4 rejects stuck in as marketing gimmick, affluent people were willing to pay $50 for a Sony.
Engineers graduating in 1960 were schooled in Vacuum Tubes and had a faint exposure to transistors. I graduated in '64 that is all I got for transistors.
A commercially viable GFI for the consumer market requires integrated circuit and a market puller such as home construction, the boat market is not large enough to stimulate such product.
Mauro Gaetano
in Austin TX

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BigDumbDinosaur
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Re: Engineers really know their stuff

Post by BigDumbDinosaur » Wed Mar 21, 2018 3:20 pm

SteveHGraham wrote:
Tue Mar 20, 2018 11:26 am
I often marvel at the dumb things bad engineers do. The recent bridge collapse at Florida International University is a fresh example. Engineers designed it, approved the plans, helped build it, and inspected it. It didn't sag and gradually come down. It fell like a brick, all at once.
Civil engineers generally don't help build bridges, although they may supervise construction. Any number of factors could have resulted in this collapse, ranging from design errors to questionable materials to construction boo-boos. That said, and given the $14 million spent to build a 200 foot bridge designed only for pedestrian use, as well as the particular locale involved, I suspect the structure's demise may have had to do with something else that involves two words that I won't post so as to avoid exciting the ire of Chaski moderators. :shock:
Science makes it known. Engineering makes it work.

tornitore45
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Re: Engineers really know their stuff

Post by tornitore45 » Wed Mar 21, 2018 3:34 pm

involves two words that I won't post so as to avoid exciting the ire of Chaski moderators. :shock:
No need to use censurable words. Skimping on materials for profit sake, cutting corners, rushing schedules.
Mauro Gaetano
in Austin TX

tornitore45
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Re: Engineers really know their stuff

Post by tornitore45 » Wed Mar 21, 2018 3:50 pm

Why are houses built the way they are?
Because unless you design and spec your custom house and know what you are doing, the typical house buying experience is driven by the glamor of high ceiling, the wine crypt, the granite counter-tops, the Hollywood inspired bathroom, and 100's of very appealing visuals, telling your friends how successful you are.
The builder know exactly what the buyer is looking for and what the buyer can not see, such as the shoddy plumbing behind the wall terminating into a shiny faucet; the $0.29 outlets with wire stuck because it save 10 seconds versus looping and screwing; the barely code number of outlets; the minimal wall insulation; the gaps leaking air; the nightmarish duct-work; the inadequate HVAC system; the water heater 5 miles of pipes from where the hot water is needed; the skimpy foundations and many corner cutting opportunities that will not be apparent until after the closing. The reality is that when money is involved doing the right thing is optional.
Mauro Gaetano
in Austin TX

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BadDog
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Re: Engineers really know their stuff

Post by BadDog » Wed Mar 21, 2018 5:33 pm

These days, if you have investors, doing the right thing can get you sued into bankruptcy if there is any way they (the investors) can frame it as not having done everything reasonable to maximized profits. Such is the world created by "long term planning is next quarter's returns" MBAs cut in the "Harvard" model...

As such, premium brands are no longer built on quality or real value. They are most often an artifact of times past (re Jacobs, Stanley, Black and Decker, etc), and are only bought/sold (in name only, or to sell off equity assets) in order to be leveraged for inflated prices (and resulting profit). Often accomplished by doing nothing more than using a particular color and/or slapping on a sticker. Modern/New brands don't seem to ever be built on quality/value, at least not in historical terms (re Harbor Freight), but rather are mostly built on successful marketing claims, often seemingly for no better reason than to ultimately sell for a huge profit, sometimes not long before the public outcry effectively kills the brand. I just refused to accept a contract to "update" just such a product. The brand is so tarnished, I don't believe there is anyway to succeed on that project, and I don't want to be associated with failing to avert it's imminent failure (IMO).
Russ
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SteveHGraham
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Re: Engineers really know their stuff

Post by SteveHGraham » Wed Mar 21, 2018 6:38 pm

A commercially viable GFI for the consumer market requires integrated circuit and a market puller such as home construction, the boat market is not large enough to stimulate such product.
This is a surprising comment. Boats are full of circuitry, and the market is gigantic. As you know, the oceans are full of huge ships full of electrical equipment. The market isn't just bass boats and retiree trawlers. Maersk and SeaLand don't want unnecessary wrongful death or negligence lawsuits, and neither do the Navy and Coast Guard. Very expensive.

GFI's are standard on yachts now. Oops...I am using the wrong term. It's "ELCI." It's a big device that protects the whole boat. But GFI's are standard, too.

When my dad bought his boat in 1988, the surveyor was afraid to go in the engine room to finish his inspection. He told us we were going to be electrocuted if an ELCI wasn't installed, so we got one. It wasn't a big deal. No research involved. The guy who worked on our boat drove to the marine supply place and picked it up.
Civil engineers generally don't help build bridges, although they may supervise construction.
Here's the money part: "they may supervise construction"

I don't know if engineers were on the scene when this bridge was built. That will come out in the investigation, civil trials, and possible criminal trials. If they were NOT on site, then the lawyers will ask why not (I would). My guess is that engineers visited from time to time.

If you were to succeed in saving civil engineers from blame in the FIU collapse, I would pull out the Tacoma Narrows Bridge.

Here's another one. I can't resist. Liberty ships. The early ones broke in half and sank in a few minutes.
Every hard-fried egg began life sunny-side up.

John Hasler
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Re: Engineers really know their stuff

Post by John Hasler » Wed Mar 21, 2018 6:46 pm

So the line of reasoning goes "An engineer made a mistake once. Therefor all engineers are incompetent."

I think that it might be just barely possible that a machinist also once made a mistake.

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warmstrong1955
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Re: Engineers really know their stuff

Post by warmstrong1955 » Wed Mar 21, 2018 7:06 pm

As far as the FIU bridge....there were lots of problems. Engineering and manufacturing engineering problems.

First of it's kind. Pre-stressed concrete/steel, one piece, built off site, and moved into place. It's a truss.
It was a suspension bridge, that was not suspended before it collapsed.
Florida decided, to make it 11 ft wider than it was designed and planned.
Moving it required changes to the original moving plan, due to the change. Mainly in the locations it was supported during the move.
Two days before it collapsed, an engineer noticed cracks.
Watch the vid, especially at 8 seconds in, when it collapsed, and note where it collapsed:
https://www.youtube.com/watch?v=Ucflj-MsJBI
Tension failure. Concrete tensile strength is 10-15% of it's compression strength, or, ie; it's whimpy when it comes to tensile strength.
Look at this pic:
florida-bridge-collapse-01-gty-jc-180315_hpmain_4x3_992.jpg
See the blue thing hangin' off the rod?
The rod, is a angled tendon.
The blue thing is a hydraulic port-a-power,. We used them all the time to tension cable-bolts in the mine, as well as test other types of rock bolts.
Now go back and watch the vid again, and stop frame as the bridge collapses. That looks to be a guy falling....the one running the port-a-power. He's in the right location.

Someone, an engineer, made the decision to re-tension the bridge. Cracks worried 'em. Just happens that's where it collapsed?
Appears to me, either the tendon broke, or lost it's fixed anchor, which is why it, and the port-a-power, are hanging out of the blister.
Other factors involved, besides the actual design:
The concrete used, and if it was mixed & slump tested to check it was mixed correctly. Was it compression tested.
Wee all the dozens of tendons tensioned to spec.
Did an engineer(s) crunch all the numbers when that section of the bridge was made 11' longer than originally designed.
I could go on.....
Just my theory.....I could be wrong, but we will find out.

:)
Bill
Today's solutions are tomorrow's problems.

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SteveHGraham
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Re: Engineers really know their stuff

Post by SteveHGraham » Wed Mar 21, 2018 7:18 pm

Construction is generally pretty bad in Miami. Walls meet at funny angles. Uneven gaps run along under baseboards. Doors don't quite close. It's the Cuban way. Build it fast and cheap, guess when you don't know, use illegal labor, and declare bankruptcy when something goes wrong.

I love the house I'm in now. The walls are straight. The floors are flat. There are no loose 220 wires with bare ends swinging in the closets. It feels like a mansion after Miami. Houses like this are common in America, but in Miami, they don't exist. Everything is crude and flashy. Even expensive houses are badly built.

Nothing that comes out of the investigation will surprise me.
Every hard-fried egg began life sunny-side up.

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SteveHGraham
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Re: Engineers really know their stuff

Post by SteveHGraham » Wed Mar 21, 2018 7:23 pm

Really interesting analysis, warmstrong. Thanks.
Every hard-fried egg began life sunny-side up.

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