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Highly recommended: Ken Burns' first-ever work for PBS: a documentary on The Brooklyn Bridge. I watched this during the past week, and I learned things I never knew; hell, I didn't even know it was so old. What a magnificent structure - Brian, I would love your opinion of it even though I realize you're not a Civil Engineer. What is the difference, for example, between a "suspension bridge" and a "cable-stayed bridge," and why is The Brooklyn Bridge a hybrid of the two? 

You didn't ask me, but I'm a total bridge freak and will attempt a simple explanation (I'm further from being an engineer of any kind than from any other profession, and simple is all I can do). In a suspension bridge, the main cables are strung between two towers, and smaller cables (sometimes called "hangers") run vertically from the main cables to the bridge deck, holding it up. In a cable-stayed bridge, cables are run directly from the towers to the bridge deck. The Brooklyn Bridge employs both kind of cabling, as you can see here:

479px-NY_Brooklyn_Bridge_IMG_2425.JPG

Among the best-known pure suspension bridges is the main section of the Golden Gate Bridge, the form of which is shown here:

600px-Golden-Gate-Bridge.svg.png

Probably the most breath-taking cable-stayed bridge is the Millau Viaduct in France, which opened in 2004:

a75b7942b6e1ba251495b1beba4a16e9.jpg

It's the tallest bridge ever built, its tallest mast being approximately twice the height of the Washington Monument.

I'm hoping to go an a bridge tour one day, and visit this and some other remarkable bridges I've never seen.

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Speaking of viaducts, I was driving along the coast of the French Riviera one day three or four years ago, between Fréjus and Cannes, when I rounded a bend and beheld this:

9839202265_404877c9c6_z_zpstqdr5uib.jpg

I said to myself "Wow!" and stopped the car to take a few pictures. This is the Viaduc d'Anthéor, a railway bridge built in the 1860s, I think, in the commune of Saint Raphaí«l. It was bombed three times by the Allies during the Second World War but never put out of service more than briefly. It formed part of an important rail link between German forces in France and Italy. It's a real stunner, don't you think?

There's no really precise definition for the term "viaduct", but it usually refers to a bridge that is substantially over land rather than, or in addition to, water. For many years I lived next to the southern end of the Taft Memorial Bridge, a magnificent viaduct and probably my favorite structure in Washington. It looked like this on the snowy afternoon of December 5, 2009:

9724596025_fabe41c2ab_z_zpscjkvoow2.jpg

Most of the photographs of this bridge that you see are from the other side, the south, from over near the Shoreham. This is from the north, on Belmont Road, the street I lived on. That's the Park Police stable in the foreground.

ETA: I realize now that my "north" and "south" references are confusing, and should really be east and west, respectively. Let's say the pictures you usually see are from the right bank, downstream, taken from near the Shoreham. This is from the left bank, upstream, taken from the 2000 block of Belmont Road.

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Speaking of viaducts, I was driving along the coast of the French Riviera one day three or four years ago, between Fréjus and Cannes, when I rounded a bend and beheld this:

9839202265_404877c9c6_z_zpstqdr5uib.jpg

I said to myself "Wow!" and stopped the car to take a few pictures. This is the Viaduc d'Anthéor, a railway bridge built in the 1860s, I think, in the commune of Saint Raphaí«l. It was bombed three times by the Allies during the Second World War but never put out of service more than briefly. It formed part of an important rail link between German forces in France and Italy. It's a real stunner, don't you think?

There's no really precise definition for the term "viaduct", but it usually refers to a bridge that is substantially over land rather than, or in addition to, water. For many years I lived next to the southern end of the Taft Memorial Bridge, a magnificent viaduct and probably my favorite structure in Washington. It looked like this on the snowy afternoon of December 5, 2009:

I'm not going to look this up before posting, but I always thought "viaducts" (via meaning "life") carried people, and "aqueducts" (aqua meaning "water") carried water - I've seen a couple of ancient Roman aqueducts in France, and they were built to carry water I *thought*.

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I'm not going to look this up before posting, but I always thought "viaducts" (via meaning "life") carried people, and "aqueducts" (aqua meaning "water") carried water - I've seen a couple of ancient Roman aqueducts in France, and they were built to carry water I *thought*.

Actually, the "via" of viaduct is Latin for road ("vita" is life). But while "aqueduct" is a word we inherited from the Romans, "viaduct" is a (relatively) modern term formed by analogy with "aqueduct". But yes, an aqueduct carries water, and a viaduct carries a roadway, but in practice not every elevated structure that carries a roadway is called a viaduct. Here in the Washington area we have a wonderful structure which is both a viaduct and an aqueduct, athough originally only the latter, the bridge known variously as the Cabin John Bridge or the Union Arch Bridge, built by the engineer Montgomery Meigs, one of those "great men" we had in the 19th century (and he was a doozie). It now conveys both the Washington Aqueduct and Macarthur Boulevard over Cabin John Parkway, and the gorge it and Cabin John Creek run through. At the time it was built, and for several decades thereafter, it was the longest stone arch in the world. We've also got a bridge right in the city, a block from where I'm writing this, that is a bridge and an aqueduct, the Pennsylvania Avenue Bridge, which incorporates water mains as structural elements.

As I say, in practice only bridges that are substantially above land are called viaducts. You'd never call the Brooklyn Bridge or the Chesapeake Bay Bridge viaducts. Here in Washington once upon a time there was another structure that was both an aqueduct and a bridge, but never called a viaduct, which was known as the Aqueduct Bridge, which linked the C&O Canal in Georgetown to the Virginia side of the Potomac, while during part of its existence it also carried a roadway across the river. Its abutment on the Georgetown side is still prominently visible, a bit upstream from Key Bridge.

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We've also got a bridge right in the city, a block from where I'm writing this, that is a bridge and an aqueduct, the Pennsylvania Avenue Bridge, which incorporates water mains as structural elements.

You've risen to enormous heights in this conversation, truly.

There's a pipe attached to the Edward Kennedy Bridge (*), and I'm wondering if it carries gas, or water. Some water mains are 72 inches in diameter, and this is only perhaps 12-24 inches - if you walk across the bridge, you can see it, pretty much just bolted to the bridge, which is why I'm guessing it carries gas, or maybe even something else.

(*) Oh. You didn't know that Teddy Kennedy had a bridge named after him? Or is it because you didn't know that this guy's name was "Edward Kennedy?" :)

And did you know that hideous, concrete *thing* with a large, beat-up parking area between the bridge and Mama Ayesha's is a restroom for Metro Bus drivers? I suspect there have been times when it's their best friend.

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Speaking of viaducts, I was driving along the coast of the French Riviera one day three or four years ago, between Fréjus and Cannes, when I rounded a bend and beheld this:

Closer to home, you might want to take a field trip to the Thomas Viaduct some day.  Not as pretty to look at, but considered an architectural marvel in its time, and it predates the one you pictured.

From http://thomas-viaduct-relay-maryland.blogspot.com/

"The Thomas Viaduct is a stone masonry railroad bridge that spans the Patapsco River and the Patapsco Valley gorge between the towns of Relay and Elkridge, Maryland and is the first multispan masonry bridge constructed in the United States to be built on a curve. It is the world's second oldest railroad bridge still in use (the oldest is the Carrollton Viaduct  located a few miles north) and is the world's largest multiple arched stone railroad bridge built on a curve."

From Wikipedia:

"During design and construction, the Thomas Viaduct was nicknamed "Latrobe's Folly" after the designer Benjamin Latrobe II, because at the time many doubted that it could even support its own weight. Contrary to these predictions, the Thomas Viaduct survived the great flood of 1868 as well as Hurricane Agnes in 1972, two floods that wiped out the Patapsco Valley and destroyed nearly everything in their path; and to this day it continues to carry 300-ton (270 tonne) diesel locomotives passengers and heavy freight traffic."

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Closer to home, you might want to take a field trip to the Thomas Viaduct some day.  Not as pretty to look at, but considered an architectural marvel in its time, and it predates the one you pictured. 

Thanks. I'll have to go take a look. Is there a vantage point where you can get a good view of the bridge? The pity of the Union Arch Bridge is that the only place where you can really see it is on Cabin John Parkway, which is not pedestrian-with-a-camera friendly.

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There's a pipe attached to the Edward Kennedy Bridge (*), and I'm wondering if it carries gas, or water. Some water mains are 72 inches in diameter, and this is only perhaps 12-24 inches - if you walk across the bridge, you can see it, pretty much just bolted to the bridge, which is why I'm guessing it carries gas, or maybe even something else.

(*) Oh. You didn't know that Teddy Kennedy had a bridge named after him? Or is it because you didn't know that this guy's name was "Edward Kennedy?" :)

And did you know that hideous, concrete *thing* with a large, beat-up parking area between the bridge and Mama Ayesha's is a restroom for Metro Bus drivers? I suspect there have been times when it's their best friend.

Are you talking about the pipe that ran along the sidewalk on the south side of the bridge? I don't know what it carried, but it was temporary and was removed several years ago. If you're talking about some other pipe, I don't know what you mean.

I posted this once before, in the Mama Ayesha thread, but it's worth another look:

CalvertStreetTurnaroundjgp_zpse27c43cb.j

That "thing" was a Toddle House in this 1947 photograph. For those too young to remember, Toddle House was a chain of tiny quick-service restaurants similar to Waffle House, but with counter seating only. The chain was absorbed by the similar Steak & Egg Kitchen, of which the sole surviving example is the one in Tenleytown, albeit with a much different bill of fare.

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Are you talking about the pipe that ran along the sidewalk on the south side of the bridge? I don't know what it carried, but it was temporary and was removed several years ago. If you're talking about some other pipe, I don't know what you mean.

...

That "thing" was a Toddle House in this 1947 photograph. For those too young to remember, Toddle House was a chain of tiny quick-service restaurants similar to Waffle House, but with counter seating only. The chain was absorbed by the similar Steak & Egg Kitchen, of which the sole surviving example is the one in Tenleytown, albeit with a much different bill of fare.

Oh my goodness - I must not have been thinking about it when I first saw the picture. I can't believe that restroom was a Toddle House!

Yes, that is the pipe I was referring to.

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Thanks. I'll have to go take a look. Is there a vantage point where you can get a good view of the bridge? The pity of the Union Arch Bridge is that the only place where you can really see it is on Cabin John Parkway, which is not pedestrian-with-a-camera friendly.

I've only seen it once, and I can't say it was a great view.  It lies just within the Avalon area entrance to Patapsco State Park.  About the Union Arch Bridge: there is a trail that goes from MacArthur Blvd down to the canal, taking you under both the Cabin John and Clara Barton Parkways.  I honestly can't recall if there's a good view of the bridge from there, but next time I'm out that way I'll have a look and report back.

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I've only seen it once, and I can't say it was a great view.  It lies just within the Avalon area entrance to Patapsco State Park.  About the Union Arch Bridge: there is a trail that goes from MacArthur Blvd down to the canal, taking you under both the Cabin John and Clara Barton Parkways.  I honestly can't recall if there's a good view of the bridge from there, but next time I'm out that way I'll have a look and report back.

I walked down a pathway to look for a place to photograph the bridge and didn't find one down there. However, as I look at the map, I think you're talking about a different path. My path led down to the creek, not the canal. I think I see your path, which is from the east and south of the bridge; mine was to the north and west, running down into the woods from the park with tennis courts.

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^That's right.  There's a small parking area at the trailhead, south side of MacArthur Blvd between Wilson Lane and the bridge.   Once the trees leaf out I'm sure any view will be totally blocked.  The other path you describe has a fantastic display of Dutchman's breeches, btw.

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The Beipanjiang Duge Bridge opened at the very end of 2016 in Southwestern China, connecting Guizhou and Yunnan provinces - just the cabling on the bridge, if it were stretched out in a straight line, would run from Beijing to New York City.

May 31, 2017 - "China's Impossible Engineering Feat" on bbc.com

Dec 31, 2016 - "Watch: The World's Highest Bridge Just Opened, and It's Terrifying" by David Nield on sciencealert.com

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