Subject:
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Re: My newest creation, Hell Gate Bridge NY
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Newsgroups:
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lugnet.trains
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Date:
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Fri, 8 Dec 2000 12:23:51 GMT
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Viewed:
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1147 times
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In lugnet.trains, Larry Pieniazek writes:
> I'm not a civil, thanks for refining my critique.
>
> In lugnet.trains, Scott Arthur writes:
> > In lugnet.trains, Larry Pieniazek writes:
> > >
> > > Well, no, I'd have to categorise it as a type of through truss.
> >
> > I was going to leave this, but now that you started...
> >
> > I agree that is not a arch, and I expect that is was modelled on a truss.
> > However, I'd call it a frame as it is pin jointed (trusses, I think are
> > not). However, to be a frame all the members have to be in _pure_ tension or
> > compression (ie no bending moments). This is not the case with Jamess
> > bridge. Additionally, the frame is statically indeterminate as it is not
> > "perfect". To be a perfect frame:
> >
> > m=2j-3
> >
> > m=the number of members
> > j=number of joints
> >
> > If it were a real structure, Id expect it to have considerable movement.
> >
> > Basically, the problem is, it is not constructed from triangles. Despite
> > that, it is fit for its intended purpose, and it does look very good.
>
> Oh, indeed, it looks nifty. It's just not an arch. I'm not competent to
> comment on whether trusses can't be pinned, though.
>
> While we are identifying arches, though, I thought Ben "April Fool" Beneke
> did one, no? I can't find it at the mo.
>
> There are others out there, I think.
>
> > {1} Durka almost schoolboy level SE
> > http://www.amazon.com/exec/obidos/ASIN/0582251990/qid=976273366/sr=1-5/106-5958974-3391625
>
> Thanks for the ref.. out of print, though. What I'd like to have is
> something more like a "bridge spotter's guide"
If we are talking bridge spotting, I'll be crossing this (road) one today:
http://www.firstcity.f9.co.uk/newgallery/out1.htm
As I cross it, I'll be looking at this (rail) one:
http://www.geo.ed.ac.uk/scotgaz/features/featurefirst1053.html
Better picture:
http://members.tripod.co.uk/dougalh/movies/forthb.html
Both are about 8 miles from my office.
Scott A
> with examples of all the
> different interesting types and discussion of when you'd see them in use,
> rather than a tome on how to analyse them... Following some refs got me to
> textbooks that cost 250 USD and up!!!
>
> ++Lar
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Message has 1 Reply: | | Re: My newest creation, Hell Gate Bridge NY
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| (...) Mighty Mac... (URL) (I've posted links to it in the past I think) (...) bridges that look like it in shape (with the inward sloping cantilever towers) or in expanse and it was a ground breaker in its day. My hero, D. B. Steinman, (1) took a (...) (24 years ago, 8-Dec-00, to lugnet.trains)
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Message is in Reply To:
| | Re: My newest creation, Hell Gate Bridge NY
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| I'm not a civil, thanks for refining my critique. (...) Oh, indeed, it looks nifty. It's just not an arch. I'm not competent to comment on whether trusses can't be pinned, though. While we are identifying arches, though, I thought Ben "April Fool" (...) (24 years ago, 8-Dec-00, to lugnet.trains)
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