Did Someone Order an Instant Bridge? | Hacker News Reader

Did Someone Order an Instant Bridge?

nytimes.com

100 pointsmoonboots37 comments

One interesting fact about these drop in construction components is that some of them are actually being manufactured in China and shipped over here:

http://www.telegraph.co.uk/news/worldnews/asia/china/8602786...

For it to be more economical to build a bridge over in China, stick it on a boat, and then drop it in place 1000 miles from where it was originally made is telling of where the construction industry is headed.

First they came for manufacturing, then they came for construction...

As someone who lives in Berlin I appreciate this reference, but is the point of this comment "speak up before all programming is done by smart thirdworlders"?

I'm not sure I get your point.

That really wasn't my point, but I didn't do a good job of developing it. In a nutshell: if nothing is done to stem the tide of entire industries being shipped from North America to China one has to wonder how long it will be before there's no economy to speak of. Yes, yes, I'm aware economics pundits would have us all believe that the glorious shift to an "information economy" is the grand way forward and anything that smacks of isolationism is to be roundly rejected (for reasons that are entirely mysterious to me), however the unemployment numbers in the US and the decline of real wages over the last 30 years suggests something else altogether.

Generally speaking, industries get shipped off to China because people in China are poorer, and will work for less money. When there are as many industries in China as in the US, they won't be poorer any more, and the flow will stop.

However, our current spate of unemployment isn't due to China - otherwise things wouldn't have suddenly gone to hell in '08 but would have gotten slowly worse as China industrialized. The decline in real wages in the US might be due to competition for natural resources from China and India and Africa and South America, but generally I'm not going to complain about things going well in countries much poorer than my own.

"Generally speaking, industries get shipped off to China because people in China are poorer, and will work for less money. When there are as many industries in China as in the US, they won't be poorer any more, and the flow will stop."

Net result: global average wages settle somewhere near what a Pakistani brickmaker would call "prosperity". What you're describing isn't a win.

That's nothing.

A few years ago, I was working doing some of the engineering for a major alumina refinery upgrade in Australia. One of the major parts of an alumina refinery is what's called a calciner, which heats the produced alumina to drive off the chemically-bound water from the product. They're complex piece of plant with large ducts, blowers and cyclones all laid out with insulating material to protect against the high temperatures and erosive nature of the alumina.

We built our calciners in Thailand as entire modules - not merely the size of a bridge, but the size of a 6-story building, complete with all equipment, structure and wiring in place, and then shipped them to the refinery site in Australia. The largest of the modules was 1800+ tons.

Ah, found a picture: Here's one of our calciners about to be offloaded from the MV Sea Baron. The crawler crane at the very right of the picture gives a sense of scale.

http://www.outotec.com/pages/page.aspx?id=34948&epslangu...

That's nothing.

The Øresund (see http://en.wikipedia.org/wiki/%C3%98resund_Bridge) was built Lego style in Spain, shipped piecewise and assembled on site.

That's nothing.

In Portland, ME, where I grew up there used to be this huge blue drydock in the harbor. Occasionally I would see whole Burke class destroyers[1] lifted up out of the water in it. The end of the Cold War meant that the navy was downsizing, though, and eventually it was decided that there were better uses for the place. It was sold to a city in Croatia, and they somehow put floats underneath and just sailed the whole thing across the Atlantic. Then they built a few oil rigs where it used to be, and sailed those down to Venezuela.

[1]http://en.wikipedia.org/wiki/Burke_class

The opposite happens, too. I heard a story of how Chinese buyers bought an old, unused steel mill - think it was in the UK - and shipped it wholesale to China. The technology used in that mill would still be profitable in the Chinese environment, even though it had been superseded in the UK.

All this shipping of buildings back and forth...this clearly needs disruption!

China's more like 7000 miles away by air:

http://www.wolframalpha.com/input/?i=distance+from+beijing+t...

And as far as putting it on a boat, sailing it across the pacific, through panama, and up the atlantic - or dropping it off in Long Beach, Oakland, Seattle, or Mexico and putting it on a train... well you do the math :)

Either way, that's a lot of diesel.

> “The highway department didn’t use to see the drivers as customers,” said Frank DePaola, administrator of the highway division for the department. “For a while there, the highway department was so focused on construction and road projects, it’s almost as if the contractors became their customers.”

This is so true in programming as well. It's very easy to be consumed by the process and neglect the purpose and end-game.

almost as if the contractors became their customers

Capture of government decisionmaking by suppliers (including external suppliers and government employees via their unions) is not so much a bug as it is a feature. (In the sense that it is not an undesirable accidental property of the system, it was the predictable desired results of actions taken by someone(s) with decisionmaking authority, not in the sense that it is socially desirable.)

To the locals this was months of pervasive "future construction" signs warning us of traffic delays, and then... nothing! Done! I thought that I lost track of time, when in reality 14 bridges were replaced in 10 weekends. That's like a half second in "Big Dig" time.

My previous memory of a replaced bridge was the Charter Oak in Hartford, which was many years of parallel bridges in various states of (con/de)struction. Science!

This is puny compared to...

In Bellevue, WA in 2008 a bridge across I-405 (at NE 8th) was constructed next to the old bridge, ANOTHER bridge constructed on the opposite side, the old bridge destroyed, and the first new bridge slid into place creating a new bridge twice as wide as the old original bridge.

Watch the video:

http://www.youtube.com/watch?v=GQNfp-Sifhc

Why was the bridge placed to the right in the first place? Could they not have placed it in its final position when construction started? (My apologies if this is a stupid question: non civil engineer here)

A guess only:

The bridge on the left used to be a two way bridge.

They could not construct the bridge right next to it since they would have had to close the original bridge (since it was so close to the new construction).

So the built it off to the side. Once it was built they opened it to traffic (temporarily) presumably to get a head start on converting the nearby roads to match the new traffic flow (which they would need to do anyway).

Then they slid it into place and the new traffic pattern is already set up. They actually could have left it off to the side but that wouldn't match the existing roads as well (too many turns).

Close, but I believe both of the bridges in the video are new. Both new ones could be constructed on either side of the old, the old destroyed (semi-surgical demolition, actually much easier without closures if both of the new bridges had been built), and the new one moved in once everything where the old bridge was was ready. There's a lot of information online about the project budgets, proposal, and general construction but I wasn't able to get any specifics from either the DOT or the structural engineers' site to see if they had anything to say about it.

Utah has been rebuilding the largest section of interstate ever for the last couple years. They've built and moved many of the bridges this way (including the longest ever in the western hemisphere). Ten years ago, they rebuilt another section of I-15 for the Olympic games. The difference in commuting experience between the two is not even remotely comparable.

It is great to see construction techniques benefiting from technology.

I lived right next to one of the bridges they replaced on I-80 in Utah. They were replacing a big stretch of the freeway so they set up a "bridge farm" where they built seven bridges on stacked cargo containers and got them ready to go. Then they load a bridge on a massive machine with hundreds of wheels and basically drive it down the one side of the existing freeway to the site of the new bridge, drop it into place, secure it, and load up another bridge. They'd drive each bridge over the bridge they had just put in place basically building their way as they went. It was amazing how quickly they did it (just 41 days which included driving the bridges into place at 0.5 mph). They did a different section with four bridges in just 48 hours. I felt they made up for the terrible I-15 reconstruction for the olympics with how smoothly this I-80 project went (and the I-15 expansion in Davis county which also used this offsite bridge construction techinque).

That is so cool. I particularly like how it leverages the existing infrastructure. In some parts of the world 'replace the bridge' is code for rip it down to the dirt, and then build a new bridge where the old one was. These guys just cut out the bad bits and put in a new section. Well done.

They did this in 2010 in Hamilton, Ontario:

"It took just 51 hours to completely replace the Aberdeen Avenue Bridge over Highway 403 this weekend … 29 hours ahead of schedule! Using conventional methods, this remarkable feat would have taken up to two years to finish. Instead, using rapid bridge replacement (RBR) technology, removing the old structure and replacing it with the new bridge took only 2 days to complete."

http://www.morrisonhershfield.com/newsroom/Pages/AberdeenBri...

I drove down route 9 twice a day for about a year (in and out of Boston), this is NOT the norm. The one bridge they were working on then was about this size and at about twice the height. It had apparently been going on for 5+ years, Mass DOT is anything BUT efficient(See Big Dig) so I wouldn't really expect this as the new norm. Also then how would they manage to pay so many people to stand around all day not working??

> A reporter asked how the new bridge would be secured to the old substructure. "It’s 400 tons," said Walter Heller ... "Nobody’s going to pick it up and take it home."

I don't think the reporter meant "secured" in the sense of preventing theft. Is a 400-ton bridge heavy enough not to rattle and damage the surrounding concrete if 18-wheelers repeatedly cross it at high speed? Or flip over if a train hits it from below?

I agree that this is obviously not what the question meant. My reading of the article is that the author was picking a bit of fun at the highway director's misunderstanding by including that. It's actually an interesting question, IMO.

It's less important in places like Massachusetts than in earthquake prone locations like Missouri, California or Washington. There, it's required that you have at least .3g worth of hold downs. (roughly anyway, it varies depending on the exact seismic zone)

While I don't think it's what the reporter meant either, at least one bridge has been stolen before. http://old.post-gazette.com/pg/11280/1180364-455.stm#ixzz1a9...

I can't find the weight of that bridge directly, nor how they arrived at the value estimate, but if I'm reading it correctly, this (http://www.steelonthenet.com/commodity_prices.html) seems to say steel scrap was going for $428/ton in October 2011, so from the "estimated $100000" we can guess that it was about 234 tons of steel.

It actually sounds relatively low risk ("What are you doing!? Moving the bridge like this here paperwork says. We never approved that! Oh must have been a mixup..")

The value is probably for a constructed bridge (i.e. includes labor), not scrap.

You're probably right: http://www.wfmj.com/story/15644204/theives-make-off-with-ent... seems to be the real source of the $100,000 number, an engineer estimating the likely replacement cost, not the value of the scrap.

Also this, http://www.dailymail.co.uk/news/article-2050015/Brothers-cha...

> Two brothers have been charged with stealing a 'haunted' western Pennsylvania bridge and selling the 15.5 tons of scrap metal for £3,160.

(I assume being in Pennsylvania they actually got dollars for it)

British newspapers tend to convert everything to pounds without citing the original figure. I find it really annoying since I can never remember the going exchange rate for GBP.

Well you never know... http://www.wtae.com/r/29413287/detail.html

I've long wondered why we don't see something similar for roads. Instead of the long disruptive process of trying to build a permanent structure in place (and later try to rip that out and put in a new one), make segments which can be dropped in place and leveled (and re-leveled) with automatic jacks - a segment breaks, or you need something wider, just pick up a segment and replace it in minutes.

Just FYI, when they say "completed" they mean "put into place". They took more than a year to build the structure and then put into place over the weekend.

Amazed to see... the clusters of workers standing around.

What a senseless waste of power! Maybe we can use the spare humans to perform protein folding calculations while waiting for the bridge to be set.

One reason road construction crews have so many people standing around is that the work is very hard. You have one guy digging in a hole in the summer sun for, say, 20 minutes. Then they pull him out and he downs some Gatorade and the next guy goes in. You really can't push much harder than that without pushing your luck with heat stroke.

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