I believe this is the same fundamental engineering method used in a swamp by Herbert's father in Monty Python and the Holy Grail. [0]
What, the curtains?
The Southern Pacific dumped in fill rock starting in 1902, and the rock sank into the sediment. But they didn't give up. They kept dumping in more rock. They still couldn't get above the water line. So they built wooden trestles on the foundation thus created. That worked, but the trestle was too weak and limited to slow trains. So eventually, the Union Pacific dumped in far more rock and built a solid rock causeway all the way across the lake. The causeway had to be raised in 1986 and strengthened.
Today, it carries long UP freight trains, part of the transcontinental main line.
[1] https://utahrails.net/pdf/UP_Great-Salt-Lake-Causeway_2007.p...
[0] https://en.wikipedia.org/wiki/Lacey_V._Murrow_Memorial_Bridg...
[1] https://en.wikipedia.org/wiki/Homer_M._Hadley_Memorial_Bridg...
[2] https://en.wikipedia.org/wiki/Evergreen_Point_Floating_Bridg...
(note -- was a bridge engineer in Seattle and did work on the old 520 bridge when we designed the retrofitted post-tensioning it in the late 90's. Among other tasks, I supervised a guy drilling holes in the bottom of the bridge with a concrete corer. )
They are virtually unsinkable!
Pretty impressive timeline for an innovative idea.
Let that sink in. They paid for the project and then stopped taking everybody’s money.
That was the plan in Chicago, too...
:-\
This does require some legislative fortitude, however, to set aside the money for real and not just spend it on other things.
The other problem I foresee is that the market is fickle. The S&P 500 reached a level in the second half of 2000 that it would not see again for over 14 years[1]. Any investment that needs to generate consistent revenue isn't going to have nearly the growth rate over the long haul that an index fund would provide. That makes the initial investment requirement significantly larger.
But otherwise, I am okay with the government owning a lot of private enterprise via index funds, so long as it has exactly the same voting power that I have. Which is to say, none.
[0] In case anyone needed the clarification, this whole discussion is about state governments; it does not really apply to the federal government for obvious reasons.
[1] Adjusted for inflation. The index did recover to the same number in 2007 just before dropping 50% in 2008.
I think there are some small optimizations we can make to this flow though, like what if the feds who printed the money held the endowment for the state and just distributed payments, instead of letting each state manage its own endowment.
Pretty much the same? Inflation, but no taxes.
Investment restricted to "government responsibility foresight" infrastructure gets enough flac already. It only takes one down turn for the "golden goose" of the investment to be spent on the buddies of who just got into office
Well, not many voters think that way...
I don't like that we as a country put off the costs of maintenance as long as possible thus creating debt for future generations, but asking the current generation to create a savings fund to pay the future generation's (non emergency) expenses is a bridge too far.
Man in Year 50: We need funding for much needed maintenance that has been neglected through sheer incompetence
Alas, tolling resumed in 2011, to pay for the complete reconstruction of the bridge. This time we are probably stuck with it, since WSDOT has grown inordinately fond of tolling as a traffic-management tool.
There is always bedrock, but in some places your pile would have to be really long to reach it:
> The gravel deposits of 100 m (330 ft) are the deepest in the south of Munich and decrease towards the north.
(from https://en.wikipedia.org/wiki/Munich_gravel_plain - not saying this is anything really extraordinary, but it's the area I'm most familiar with)
They were determined to hit bedrock, but yeah, was buried too deep. [1]
[0]: https://teara.govt.nz/files/p-8788-gns.jpg
[1]: https://www.stuff.co.nz/national/117150792/awardwinning-otir...
The word has become genericized to a degree. One the other hand Alps used to be one very specific mountain range, and alp a mountain in that mountain range, so surprise at some other place calling their mountain range Alps is understandable.
yes, if you come from Wellington in Suffolk and you fly to Wellington in NZ, and then encounter that the nearby mountains are called Alps, you would be shocked, shocked
(Personally, I think it's a silly name. The Cascades are majestic enough in their own right and need no comparison to any other mountains.)
> The tagline of the Pile Driving Contractors Association is “A Driven Pile is a Tested Pile” because, just by installing them, you’ve verified that they can withstand a certain amount of force. After all, you had to overcome that force to get them in the ground. And if you’re not seeing enough resistance, in most cases, you can just keep driving downward until you do!
I feel that the cases in which that technique doesn't work are stories to be told. Do you just keep driving downward for a very long time? How long?
> What the heck?
From a structural PoV, an extremely long piling in soft-ish soil will start having problems with lateral deflection - which it is too thin (relative to length) to resist. Then there's the case of "we think we finally hit bedrock...but what if it's just a big boulder?".
I can imagine cases of pilings running into large underground caverns, or penetrating strata containing water / gas / petroleum under pressure.
Edit: From a quick search...
In some locations, bedrock may not start until >1000' below the surface.
And here's a very quick & simple intro to the fact that "bedrock starts at depth D" is usually too simplistic: https://education.nationalgeographic.org/resource/bedrock/
Example being the Lake Peigneur disaster.
https://64parishes.org/entry/lake-peigneur-drilling-accident
On the morning of November 20, 1980, the crew drilling near the salt mining operations reported that the tip of their drill shaft was stuck. After the crew removed the tip, they heard strange noises and abandoned the platform in the nick of time. A giant mud crater began sucking down barges, rigs, and almost some fishermen who escaped with moments to spare.
Doesn't matter.
There's two types of pile support: noncohesive and cohesive. Which can be thought of as end (bearing) resistance and side (friction) resistance.
Most people only think of end resistance.
Most end resistance piles aren't driven to bedrock or even a boulder, but a strata of soil with sufficient strength. Usually a layer of sand under silt or clay, but a boulder could do it.
Here's the catch- if it's a one-off, then adjacent piles won't hit it, and you'll see the anomaly. Mitigation may or may not be required. If it's not, then you've hit a strong (noncohesive) layer of boulders.
Either way- it goes back to the point: each pile is resistance tested. And you know now not only the insitu soil strength, but also that of each layer to reach that depth.
Also side note- the act of driving and then post-drive settling both build addl strength. Eg, The force used to drive the pile, applied a few months later, usually won't be sufficient to drive it any further.
https://en.wikipedia.org/wiki/Staufen_im_Breisgau#Geothermal...
https://www.researchgate.net/figure/Comparison-of-signatures...
These can be anywhere things that shoot liquid mud out of the ground to areas of very deep low seismic velocities where you could drive a pile thousands of feet to the bottom of hell and barely get any resistance.
Much the same, one should be careful when drilling into mud layers
Fascinating, thanks!
wow.
> there were no human deaths, three dogs were reported killed. All 55 employees in the mine at the time of the accident escaped
omF...g the mine was active!? and folks were just drilling on top of it!???
huh. good old 1980s.
How does this make sense or have any coherency?
Everything else you do is there just to reduce the odds of users tests catching anything. But you don't get any certainty before that step... that happens after your software is on production and people depend on it.
(Of course, that's a worldview that can be either very beneficial or incredibly harmful depending on what you are creating. It's not good to see it applied to bridges, but I believe the OP did it in jest.)
I suspect, but don't have data on, that wooden piles may actually last longer in those exact circumstances due to galvanic issues with concrete and rebar or metal pilings.
Parts of Amsterdam as well.
When building fences, the ground-air interface is often where rot occurs, and there are products to protect that area:
* https://www.postsaver.com/en-gb/products/pro-sleeve-fence-po...
Stones could help with drainage and drying as well.
This is because the shapes are different. I beams are typically more slender through the web because the goal is to concentrate mass at the flange for moment capacity because they’re beams and geared towards bending. H piles are thicker in the web with the web thickness usually similar to the flange because the use case requires axial capacity and various constructability considerations. I beams turned into W (wide flange) and S sections in the standard shapes and H beams are called HP sections.
You’ll often see them cross-specified for foundation work but it’s rare that you’d choose an HP section over a more efficient section like a W or S for something “out of the ground.”
Useful graphic: https://en.wikipedia.org/wiki/File:I-BeamCrossSection.svg
The Great Bridge: The Epic Story of the Building of the Brooklyn Bridge by David McCullough
https://www.amazon.com/Great-Bridge-Story-Building-Brooklyn/...
Wait, I just checked the page source after writing the above to confirm and it looks like it does have one: https://practical.engineering/blog?format=rss
Even authors are probably not aware of this.
Videos: https://www.youtube.com/channel/UCMOqf8ab-42UUQIdVoKwjlQ