SWPKO #6

[swp]

Congratulations on making it to Round 6.

The contest is now open to Pete, Dan Blum, Dan Tilque, Joshua Kreitzer, Calvin,
Mark Brader, and Erland Sommarskog.

***
#6. The Ikitsuki Bridge in Nagasaki Prefecture, Japan,
has the longest main span in the world. How long?

(you may answer in feet or meters, but I will convert to feet for the results posting)
***

swp

[Mark Brader]

Stephen Perry:

> #6. The Ikitsuki Bridge in Nagasaki Prefecture, Japan,
> has the longest main span in the world. How long?

And here I thought the longest was a bridge with a name something
like Asashi-Kaikyo Bridge (Asashi isn't exactly right), also in
Japan. I think that one is just over 2 km, so I'll guess

2100 m.
--
Mark Brader | "What ever happened to the concept of 'less is more'?"
Toronto | "Ah, but if less is more, then just think how much
m...@vex.net | more more would be." -- Frasier (David Lloyd)

My text in this article is in the public domain.

[Pete]

swp <Stephen...@gmail.com> wrote in
news:b9092013-e3a6-4ddf...@googlegroups.com:

5000 feet

Pete

[Joshua Kreitzer]

swp <Stephen...@gmail.com> wrote in
news:b9092013-e3a6-4ddf...@googlegroups.com:

50,000 feet

--
Joshua Kreitzer
grom...@hotmail.com

[swp]

I made a mistake in bridge terminology. The one in this question is the
'longest continuous truss bridge' in the world. It doesn't change the question
or the answer, but I do regret the lack of clarity in the question so I will email you and the others who have already entered to allow them to change their answers based on this clarification if they so choose.

swp

[swp]

I made a mistake in bridge terminology. The one in this question is the
'longest continuous truss bridge' in the world. It doesn't change the question
or the answer, but I do regret the lack of clarity in the question so I will

allow you to change your answer based on this clarification if you so choose.

swp

[Dan Blum]

6000 feet

--
_______________________________________________________________________
Dan Blum to...@panix.com
"I wouldn't have believed it myself if I hadn't just made it up."

[Mark Brader]

Stephen Perry:
>>> #6. The Ikitsuki Bridge in Nagasaki Prefecture, Japan,
>>> has the longest main span in the world. How long?

Mark Brader:

>> And here I thought the longest was a bridge with a name something
>> like Asashi-Kaikyo Bridge (Asashi isn't exactly right), also in
>> Japan. I think that one is just over 2 km, so I'll guess
>>
>> 2100 m.

Stephen Perry:

> I made a mistake in bridge terminology. The one in this question is the
> 'longest continuous truss bridge' in the world.

Oh. In that case I have absolutely no idea. My first thought was
that it's something comparable to the bridges over Great Salt Lake
and Lake Pontchartrain (which aren't trusses, of course, but they
could just as well have been if that design had been preferred).
But since you're scoring by difference and not ratio, there's more
room for error on the high side, so I'll guess lower -- a nice round

10,240 m.

> It doesn't change the question or the answer,

Er, yes, it does change the question. As well as the words being wrong,
the engineering constraints on long-span and many-span bridges are quite
different.

> but I do regret the lack of clarity in the question

You mean "error".

> so I will email you and the others who have already entered to allow
> them to change their answers based on this clarification if they so choose.

Best to email the entire list of eligible entrants, so that those who
*haven't* already entered have the best possible chance to see the
correction before reading someone else's answer. You should have
changed the subject line too, but too late now.

(Posted and emailed.)
--
Mark Brader | "To a security officer the ideal world was one where
Toronto | nobody talked to anyone else... [But] of course...
m...@vex.net | such a world rarely did anything worth securing
| in the first place." -- Tom Clancy

[Erland Sommarskog]

swp (Stephen...@gmail.com) writes:
> ***
> #6. The Ikitsuki Bridge in Nagasaki Prefecture, Japan,
> has the longest main span in the world. How long?
>
> (you may answer in feet or meters, but I will convert to feet for
> the results posting)
> ***

Now, if I had known about that bridge... Or at least known what a
"continuous truss bridge" is...

8400 metres


--
Erland Sommarskog, Stockholm, esq...@sommarskog.se

[Erland Sommarskog]

swp (Stephen...@gmail.com) writes:
> I made a mistake in bridge terminology. The one in this question is the
> 'longest continuous truss bridge' in the world. It doesn't change the
> question or the answer, but I do regret the lack of clarity in the
> question so I will email you and the others who have already entered to
> allow them to change their answers based on this clarification if they
> so choose.
>

Having looked up the bridge on Wikipedia, my suggestion is that you simply
drop this question and try another. After seeing the correction from Mark
in the mail, I thought you wanted the length of the bridge, which my
answered was based on, and I guess so was Mark's. Judging from the picture,
our answers are completely off the mark, but what is more interesting is
that Wikipedia does not even give the length of the bridge, only the main
span, but there seem to be more than one span.

[calvin]

567 metres

--
cheers,
calvin

[Mark Brader]

Mark Brader:

> And here I thought the longest was a bridge with a name something
> like Asashi-Kaikyo Bridge (Asashi isn't exactly right), also in

> Japan. I think that one is just over 2 km...

By the way, the correct name is Akashi-Kaikyo Bridge, and the main span
is only 1.99 km.
--
Mark Brader, Toronto "Do people confuse me with Mark Brader?"
m...@vex.net --Mark Barratt

[Mark Brader]

Erland Sommarskog:

> Having looked up the bridge on Wikipedia, my suggestion is that you simply
> drop this question and try another. After seeing the correction from Mark
> in the mail, I thought you wanted the length of the bridge, which my
> answered was based on, and I guess so was Mark's.

Considering that the words "main span" were deleted from the question,
I thought it was clear that we were talking about the length of the
continuous truss.

> Judging from the picture,
> our answers are completely off the mark, but what is more interesting is
> that Wikipedia does not even give the length of the bridge, only the main
> span, but there seem to be more than one span.

It's simply wrong: where it says "longest continuous truss bridge", it
means "continuous truss bridge with the longest main span". This is
obvious if you follow the link to "List of longest continuous truss
bridge spans".

With most types of bridge it is appropriate to consider only the main
span length, but since a continuous truss is a single structure that
may extend over many spans, it is at least as sensible to compare them
according to the total length.

That article also contains a small list of continuous truss bridges by
overall length of the continuous truss, but (1) it takes the view that
any expansion joint terminates the continuity, and (2) it only has four
listings. The longest one that it gives is the Dashengguan Bridge in
China, with 6 spans totaling 1,272 m.

But if you disagree with the position taken on expansion joints, then
obviously there are still longer continuous truss bridges. Again
according to Wikipedia, the Kingston-Rhinecliff Bridge in New York
(state) is 2,375 m long and pictures show at least 8 spans of the
continuous truss structure.


I can't find a source that addresses the question actually asked.
--
Mark Brader, Toronto | "The time to make up your mind about people
m...@vex.net | is never." --The Philadelphia Story

[Dan Tilque]

8700 ft

--
Dan Tilque

Helix, if everything goes according to plan, the plan has been
compromised. -- Sam Starfall in "Freefall"

[swp]

this round is tossed. I'll post a replacement with less ambiguity in a few minutes.

swp

[Dan Tilque]

swp wrote:
>
> this round is tossed. I'll post a replacement with less ambiguity in a few minutes.

That's probably for the best.

The thing is, immediately after posting my answer and before reading any
of the rest of the thread, I looked up the actual answer on Wikipedia.
So I couldn't have fairly posted a corrected answer, anyway. If you'd
made a post with a subject line like "READ THIS BEFORE ANSWERING", then
things may heve been different.

BTW, I got my answer by assuming you meant all kinds of bridges and I
knew the Golden Gate Bridge has a main span of around 4000 ft. I guessed
bridge making technology had managed to about double that distance in
the 70-odd years since it was built, so I guessed a number in that range.

[Erland Sommarskog]

Mark Brader (m...@vex.net) writes:
> But if you disagree with the position taken on expansion joints, then
> obviously there are still longer continuous truss bridges. Again
> according to Wikipedia, the Kingston-Rhinecliff Bridge in New York
> (state) is 2,375 m long and pictures show at least 8 spans of the
> continuous truss structure.

Bridge engineering is not one my prime subjects, but truss bridges are
fairly common constructions, and I guess building long such bridges is
no big deal if the water is shallow enough. Ponte Vasco da Gama in Lisbon
is 17.5 km. Wikipedia has it as cable-stayed, but that is only a shorter
passage close to one of the landings.

I guess what migh excite some people is exactly the continuity - how much
you permit to expand for temperature.

Anyway, it seems that Stephen has followed my advice and posted a
replacement question, so we can let this one lie.

[Mark Brader]

Erland Sommarskog:

> Bridge engineering is not one my prime subjects, but truss bridges are
> fairly common constructions, and I guess building long such bridges is
> no big deal if the water is shallow enough. Ponte Vasco da Gama in Lisbon
> is 17.5 km. Wikipedia has it as cable-stayed, but that is only a shorter
> passage close to one of the landings.

The non-cable-stayed section isn't a continuous truss, though; like most
modern multi-span road bridges, it's a concrete beam bridge.

> Anyway, it seems that Stephen has followed my advice and posted a
> replacement question, so we can let this one lie.

Okay.
--
Mark Brader, Toronto, m...@vex.net
If ... it seems easier to subvert UNIX systems than most other
systems, the impression is a false one. The subversion techniques
are the same. It is just that it is often easier to write,
install, and use programs on UNIX systems than on most other
systems, and that is why the UNIX system was designed in the
first place. -- Frederick T. Grampp & Robert H. Morris

[Erland Sommarskog]

Mark Brader (m...@vex.net) writes:
> The non-cable-stayed section isn't a continuous truss, though; like most
> modern multi-span road bridges, it's a concrete beam bridge.

I said it. I'm not a bridge engineer. :-)