Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

A bigger problem than ISIS: The Mosul Dam is failing

newyorker.com

Post reply on HN
Print view View original

101–110 of 179 posts

Re: A bigger problem than ISIS: The Mosul Dam is failing

#101

Post by Hondor »

Way down the bottom, we see the problem is solved for at least the next year:

"Early in 2016, under American prodding, the Iraqis reopened negotiations with Trevi S.p.A., the Italian firm. In September, a team of engineers, hired at a cost of three hundred million dollars, arrived at the dam to perform a crash repair job. Their main task is to install updated equipment, designed to fill the voids beneath the dam more precisely, and to repair the broken control gate. Under the contract, the Italians will do the grouting for a year, and then leave the equipment with their Iraqi counterparts. The engineers say that they are confident they can prevent the dam’s foundation from washing away."

Re: A bigger problem than ISIS: The Mosul Dam is failing

#102

Post by jamesfe »

taspeotis wrote: post #59

Previous discussion [1]. [1] https://news.ycombinator.com/item?id=11209228

I came here to note this. People bring this up every year or so - when I was in Iraq in 2006, this was an issue of the "any moment they could all die" sort but nobody seems to care enough to fix it since there isn't a firm timeline for the dam failure. Also, there's that whole war thing going on.

Re: A bigger problem than ISIS: The Mosul Dam is failing

#103

Post by huxley »

magaman69 wrote: post #55

if isis can ruin more dams; why arent they a bigger problem?

Because this particular dam happens to be upstream to some large population centres, back in 2007 they estimated half-million people could be killed and several millions displaced, that figure might be higher today.

Re: A bigger problem than ISIS: The Mosul Dam is failing

#104

Post by jimnotgym »

berntb wrote: post #87
yalogin wrote: post #85

The saddest part of the article is the US tried to blow the dam up during the gulf war. Why? That is as brutal as dropping the nukes on Japan.

Uh, what article are you reading? Or do you think bombing a generator is to "blow up the dam"? The quote is: "the dam had been built to survive an aerial bombardment. (In fact, during the Gulf War, American jets bombed its generator, but the dam remained intact.)" (A dam with bad air defense ought to be an easy target, considering all the emphasis the Americans puts into getting through lots of cement -- and that dam…

bombed generator not dam....bombing dams was banned under the Geneva conventions.

"According to Article 56 of the 1977 Additional Protocol I to the Geneva Conventions, “works or installations containing dangerous forces, namely dams, dikes and nuclear electrical generating stations, shall not be made the object of attack, even when these objects are military objectives, if such attack may cause the release of dangerous forces and consequent severe losses among the civilian population.”

Re: A bigger problem than ISIS: The Mosul Dam is failing

#105

Post by abduhl »

Someone wrote: post #68
abduhl wrote: post #40

Earlier quoted context omitted.

Driving concrete piling has generally been abandoned in USA/Canada/Western Europe due to the propensity of concrete to crack in tension during pile driving operations. Driven pile is typically steel now in most construction you will see unless you live in a place where concrete is extremely cheap compared to steel.

Wouldn't that be to crack in compression ? Also, I don't see concrete piles being abandoned at all. Part of the reason may be that, where I live, many poles now are drilled, pressed or vibrated into the ground to decrease noise and potential impact on surrounding buildings. Thats is possible because there is no bedrock to build on where I live, so poles often go down easily for the first meters; I have seen wooden po…

No, tension is what I meant.

Imagine the pile hammer hitting the top of the pile. This impulse is transmitted down the length of the pile at the speed of sound as a wave. There exists a point where the wave gets to the end of the pile (this is at the pile tip) and the compression front attempts to continue which results in tension (eg - the pile tip is dragging itself forward with the energy). This is mostly seen with soft soils where end reaction is not sufficient to provide a hard "stop" on the pile.

For hard ground, the opposite can occur where the driving energy reflects at the pile tip. This can result in huge compressive forces that crush (not crack) the concrete due to the two compressive waves (one new wave from the next hammer strike and the reflected wave from the previous hammer strike) stacking due to superposition.

The reason that this failure mechanism wasn't noted by me is that steel piles suffer the same issue, so it is not a good reason to use steel over concrete piling.

As you note, the solution to both issues is the use of a shoe and control of the hammer stroke.

I should have been more clear, I guess. Driven concrete pile is not used in the USA/Canada in my experience. When deep concrete foundations are used they are typically drilled in, for the reasons cited above.

There are obviously times when concrete piles are cheaper and will get the job done even with the risks above. This is most likely for smaller buildings where loadings are relatively light and pile lengths are therefore short.

Re: A bigger problem than ISIS: The Mosul Dam is failing

#106

Post by cromulent »

Someone wrote: post #68
abduhl wrote: post #40

Earlier quoted context omitted.

Driving concrete piling has generally been abandoned in USA/Canada/Western Europe due to the propensity of concrete to crack in tension during pile driving operations. Driven pile is typically steel now in most construction you will see unless you live in a place where concrete is extremely cheap compared to steel.

Wouldn't that be to crack in compression ? Also, I don't see concrete piles being abandoned at all. Part of the reason may be that, where I live, many poles now are drilled, pressed or vibrated into the ground to decrease noise and potential impact on surrounding buildings. Thats is possible because there is no bedrock to build on where I live, so poles often go down easily for the first meters; I have seen wooden po…

My understanding is that concrete resists the compression of the ram impact well, but the shock wave reflects back and causes tension which then triggers failure. This tension is the point that needs to be controlled.

Re: A bigger problem than ISIS: The Mosul Dam is failing

#107

Post by madaxe_again »

reactor4 wrote: post #94
impostervt wrote: post #14

Dexter Filkins, the writer of this piece, is also the author of one of the best non-fiction books I've ever read - The Forever War (not the space war book). The Forever War https://www.amazon.com/dp/0307279448/ref=cm_sw_r_cp_api_OWDy...

You've got to be kidding me. I started reading "The Forever War" (the space war book) based on some comments I read on here and I assure you that there wasn't any warning about the space war book.

If you want a good space war book, Cixin Liu, Three Body Problem and sequels.

The Forever War (not the space war book) is excellent however.

Re: A bigger problem than ISIS: The Mosul Dam is failing

#108

Post by mcphilip »

emp_zealoth wrote: post #53
nyolfen wrote: post #41

Earlier quoted context omitted.

it's gotten a lot of buzz lately, including on HN, but if you're interested in going down the gaddafi hole a bit further i'd recommend the recent adam curtis film, hypernormalisation. his films tend to be a bit like getting lost in a wikipedia hole in their own right, though.

Seconded Then watch Only The Dead (see the end of a war) by an australian bloke Good luck sleeping afterwards

No joke, just finished watching HyperNormalisation[1].

The most depressing part to me is that Adam Curtis isn't off on an easily dismissed tangent in this documentary, he's essentially cross cut the last 40 years into a 3 hour cliff notes guide to some of the darker corners of postmodern philosophy.

Specifically, Baudrillard. His 2002 essay, The Violence of the Global[2] has some interesting food for thought:

>We believe that the ideal purpose of any value is to become universal. But we do not really assess the deadly danger that such a quest presents. Far from being an uplifting move, it is instead a downward trend toward a zero degree in all values. In the Enlightenment, universalization was viewed as unlimited growth and forward progress. Today, by contrast, universalization exists by default and is expressed as a forward escape, which aims to reach the most minimally common value. This is precisely the fate of human rights, democracy, and liberty today. Their expansion is in reality their weakest expression.

HyperNormalism is bleak and offers no solutions for course correcting international affairs, and there's the rub: universal solutions may not exist.

For me, my mind's left reeling by the complexity of the times, leaving me at a loss for how to integrate information from sources like Baudrillard into my worldview guiding day-to-day behavior. My typical response is a hyperlocal focus on the people around me in meatspace and trying to at least get the basics right like the golden rule.

[1]https://www.youtube.com/watch?v=-fny99f8amM

[2]http://www.ctheory.net/articles.aspx?id=385

Re: A bigger problem than ISIS: The Mosul Dam is failing

#109

Post by dajohnson89 »

PhasmaFelis wrote: post #64
dajohnson89 wrote: post #56

Earlier quoted context omitted.

But this issue with the dam was apparent before ISIS, no?

The constant infusion of concrete isn't an emergency measure. It's how the dam was intended to operate. The problem (from the planners' point of view, anyway) isn't that it requires constant grouting, it's that it stopped getting constant grouting.

My broader point is that a dam which requires constant grouting seems like a pretty bad idea.

Re: A bigger problem than ISIS: The Mosul Dam is failing

#110

Post by Pxtl »

reactor4 wrote: post #94
impostervt wrote: post #14

Dexter Filkins, the writer of this piece, is also the author of one of the best non-fiction books I've ever read - The Forever War (not the space war book). The Forever War https://www.amazon.com/dp/0307279448/ref=cm_sw_r_cp_api_OWDy...

You've got to be kidding me. I started reading "The Forever War" (the space war book) based on some comments I read on here and I assure you that there wasn't any warning about the space war book.

Haldeman's space war book "forever war" is rather good though.
Post reply on HN