Subject:
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Re: Long Span Suspension Bridge?
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Newsgroups:
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lugnet.trains
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Date:
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Wed, 23 Jan 2008 15:27:40 GMT
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Viewed:
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14230 times
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In lugnet.trains, Dave Sterling wrote:
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Stacy and I are designing a small layout for Brickworld this year and we
want/need to have a bridge in the layout. We’ve been working to design the
layout using banquet tables (so I don’t have to bring my own tables), yet we
still want an open space in the center. The way we have it designed
necessitates us to try and span 40 inches (128 studs) unsupported.
So here’s the question...has anyone built an unsupported truss-style bridge
that’s around a 128 stud unsupported span? I’m thinking if I sandwich the
deck (4x10 and 6x10 plates) between 1x8 bricks (below) and 1x16 Technic bricks
(above) and then use a standard truss structure with Technic bricks and beams,
I stand a chance of being able to support the bridge and the weight of one
train on it. However, I would love to hear some anecdotal evidence that this
works before I hit Bricklink and spend a bunch on plates, bricks, and beams to
complete this behemoth.
-Dave
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Well after reading your post one last time before I sent this I realized you
wanted info on truss designs for a suspension bridge (like the Golden Gate) not
a cable stay. But the second post threw me off due to the same problem I have
had that was fixed with tensioned string underneath bridge deck.
But for this I have a bridge I’m working on now that is 128 studs between each
support tower. I need no extra support for this besides the track getting locked
to the rest of the displays on the ends. And all the towers were connected with
Baseplates at the bottom. But I would think if this arch was above the RR track
for a suspension bridge, then you would need some downward force to keep bridge
from bouncing and warping while trains cross. I have used tensioned string
underneath bridge deck and/or adding more weight then the bridge it self with
trains to the deck (see below)
Wrong info below, but good info.
I made this version that was 10 ft long. I had to add the string on the bottom
to keep bridge level while trains went over the deck.
I then tried to double the length while giving it a pivot point so it could be
raised. You can not tell in these pictures but I have many strings holding the
deck down and keep it from bouncing while trains go over.
Total length 15ft (480 studs) , with one side of the deck over 12ft long. The
12ft length is just to long for cable stay. The bridge is too light for the use.
But if I added weight to the bridge deck, say $30+ of pennies across deck it
stabilized it. And when the very light trains went over it they did not bow any
of the deck.
My Brickshelf bridge folder
http://www.brickshelf.com/cgi-bin/gallery.cgi?f=49251
Mike Gallagher
MIKESLEGO
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Message has 2 Replies:
 | | Re: Long Span Suspension Bridge?
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| (...) Mike- The 192 stud (10 ft) cable-stayed bridged that I posted a picture of earlier in this thread has a middle open span of 96 studs (5 ft). When we originally designed it, we made the deck just 5 plates thick with the intention of having the (...) (16 years ago, 23-Jan-08, to lugnet.trains, FTX)
| | | Re: Long Span Suspension Bridge?
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| (...) Sorry wrong math the bridge were A 10ft (12 32x32 Baseplates) (384 studs) B 15 ft (18 32x32 Baseplates) (576 studs) Also forgot link to current bridge (URL) mike (16 years ago, 24-Jan-08, to lugnet.trains, FTX)
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Message is in Reply To:
| | Long Span Suspension Bridge?
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| Stacy and I are designing a small layout for Brickworld this year and we want/need to have a bridge in the layout. We've been working to design the layout using banquet tables (so I don't have to bring my own tables), yet we still want an open space (...) (16 years ago, 22-Jan-08, to lugnet.trains, lugnet.town)
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