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Subject: 
Re: Large arch bridge geometry - help!
Newsgroups: 
lugnet.technic
Date: 
Thu, 4 Jul 2002 21:02:05 GMT
Viewed: 
568 times
  
In lugnet.technic, Ross Crawford writes:
In lugnet.loc.pt, Pedro Silva writes:
Hi all,

I am attempting to design a large ached bridge with technic parts, and this
means I'll need plenty of reading on the subject of beam-geometry. Can any
of you guys help me out in my research?
The thing that is giving me the biggest headache so far is the relation
between angles possible with LEGO beams, the only sure stuff I know is the
famous 3-4-5 triangle and that is not much help for this :-(
My ultimate purpose is to design in LEGO something that ressembles either
one of the two mettalic bridges in the following link:

Pedro,

I found it easier to think in terms of beam length, rather than angles. If
you have a good profile view of the bridge, one way is to overlay it with
graph paper (or just use a ruler) to measure the beam lengths, then match
them as closely as you can with LEGO. This will probably require some trial
& error to get it looking right.

I'll try this method now - it seems easy enough. The reason I had not tried
it before was because I wanted to find a more "general" fashion to design the
arch, and then apply to my planned bridge. It is better in theory, but
failed in practice :-/

The hardest part is getting the truss structure as thin as possible. One of
the best resources for that is TJ Avery's http://www.texbrick.com/ - look
under his ideas section.

TJ's page is great, and I am still checking the link (it has plenty of
information, which I must digest slowly). Looking good so far, and it even
gave me a new idea for the bridge's "accesses" (the viaducts on either side
of the main bridge?)

You might also want to check out my bridge
http://www.brickshelf.com/cgi-bin/gallery.cgi?f=3057 8?) but there's not
much technical info there 8?(

:-)
I know your bridge. She is *the* bridge to which all others bow, mate!

Thank you for the tips!


Pedro



Message is in Reply To:
  Re: Large arch bridge geometry - help!
 
(...) Pedro, I found it easier to think in terms of beam length, rather than angles. If you have a good profile view of the bridge, one way is to overlay it with graph paper (or just use a ruler) to measure the beam lengths, then match them as (...) (22 years ago, 4-Jul-02, to lugnet.technic)

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