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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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"Dave Sterling smsrallysport.com>" <dave@ <spamsucks> wrote in message
news:Jv2A1L.BAr@lugnet.com...
> 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
If you use a tensioned string support system underneath, you can go long
distances with few parts.
-Rob
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In lugnet.trains, Dave Sterling wrote:
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..has anyone built an unsupported truss-style bridge
that’s around a 128 stud unsupported span?
|
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..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
|
How about some anecdotal pictures?
This cable stayed bridge spans 192 studs and this arched truss bridge spans 288:
This over truss bridge spans 192 studs:
This under truss spans 192 studs and passed the 16 pound bowling ball in the
middle test with minimal deflection:
We have a new generation 192 stud long bridge in the most recent layout that’s a
combination under and over whose longest Technic brick is 8 studs. For some
reason, we didn’t post any views of them on scltc.org. I can send you some
photos if you want.
-Ted
SCLTC
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In lugnet.trains, Ted Michon wrote:
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In lugnet.trains, Dave Sterling wrote:
| |
..has anyone built an unsupported truss-style bridge
that’s around a 128 stud unsupported span?
|
| |
..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
|
How about some anecdotal pictures?
SNIP
We have a new generation 192 stud long bridge in the most recent layout
that’s a combination under and over whose longest Technic brick is 8 studs.
For some reason, we didn’t post any views of them on scltc.org. I can send
you some photos if you want.
-Ted
SCLTC
|
Ted,
Once again, you come through in spades! You always seem to have the answers I’m
looking for. Do you have a Brickshelf folder or image gallery on the web where
I can find a bunch of close-up pictures of your truss bridges? I want to get a
better idea of how you built the joints. Also, pictures of that new bridge
would be sweet. :-)
Thanks!
-Dave
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In lugnet.trains, Dave Sterling wrote:
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.. Do you have a Brickshelf folder or image gallery on the web
where I can find a bunch of close-up pictures of your truss bridges? I want
to get a better idea of how you built the joints. Also, pictures of that new
bridge would be sweet. :-)
Thanks!
-Dave
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Dave-
All our public images are posted on the SCLTC website.
This
link will take you to every photo that contains a bridge. Just click on the
ones that interest you for a larger image.
I’ll gather some photos of the newest bridge and send them your way this
evening.
-Ted
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In lugnet.trains, Dave Sterling wrote:
| |
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 built one a couple of years ago that spans 128 studs, with two tracks. It’s
pretty minimal. I used double 1x16 technic bricks to support the deck, then
combinations of technic bricks for the trusses. The deck is just strips of 2x16
plates with the track on top. The nice part is that it breaks down flat for
easy transportation.
I hunted around and found a few photos from old shows.
Side view:
Overhead:
Beneath:
Upper:
-Elroy
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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.
Here's a 288 stud bridge Bob Kojima built:
http://www.brickshelf.com/cgi-bin/gallery.cgi?i=2334461
Hit next to see a few more pictures.
Frank
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In lugnet.trains, Dave Sterling wrote:
| |
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
|
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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In lugnet.trains, Dave Sterling wrote:
> 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
Dave,
I built a 128-stud, truss style bridge for NGLTC shows that's become a staple of
the layout. I use ZNAP as structural "members" to go over the tracks. The
bridge does not use any support other than the compression between two tables.
(this is because NGLTC tables are 4x4 baseplates. We have a water table that is
situated lower than the other tables--so a bridge was needed for trains to
cross.
If you do want to make a truss bridge, I recommend using layers of plates (as
there is a greater surface adhesion (clutch power) of plates when compared to
bricks. One thing that I have found that works well to to use two layers of
plate between two technic bricks. The spacing of two plates between two technic
bricks is such that you can position a 3-stud wide technic beam upright, where
the technic bricks will match holes 1 and 3 perfectly. You will most
undoubtedly need one baseplate on either side of the span to build some
supports.
My bridge has been holding together well, and is not covered with plexiglass
sneezeguards on our layouts, so it has born the bront of many children's fingers
leaning against it.
I'm trying to remember if I've brought the bridge to a BrickFest. I can send
you some pictures if you're interested.
Scott Lyttle
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In lugnet.trains, Mike Gallagher wrote:
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,,
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.
.. Mike Gallagher
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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 “cables” support the weight. We quickly determined that it was easier to
make the cables look cosmetically correct using bungee material (to take up
slack), but this proved impractical for supporting the thin deck. So we added a
truss under the deck so that even with twin heavy trains at random locations we
don’t get much deflection. Seems to work.
My next goal is a 384 stud (20 foot) suspension bridge with a 192 stud (10 foot)
middle section using real cable. The biggest problem I see is anchoring the ends
(cable stayed bridges have their advantages!).
-Ted
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In lugnet.trains, Scott Lyttle wrote:
| |
In lugnet.trains, Dave Sterling wrote:
| |
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.
|
SNIP
If you do want to make a truss bridge, I recommend using layers of plates (as
there is a greater surface adhesion (clutch power) of plates when compared to
bricks. One thing that I have found that works well to to use two layers of
plate between two technic bricks. The spacing of two plates between two
technic bricks is such that you can position a 3-stud wide technic beam
upright, where the technic bricks will match holes 1 and 3 perfectly. You
will most undoubtedly need one baseplate on either side of the span to build
some supports.
My bridge has been holding together well, and is not covered with plexiglass
sneezeguards on our layouts, so it has born the bront of many children’s
fingers leaning against it.
I’m trying to remember if I’ve brought the bridge to a BrickFest. I can send
you some pictures if you’re interested.
Scott Lyttle
|
Wow! This has all been great information and the pictures are wonderful. I’m
really excited to get a closer look at some of these bridges at various shows
this summer. :-) I might even have to get out to somewhere where SCLTC is
displaying sometime!
So, last night I went home and quickly put together a 92-stud prototype bridge
and tested it. My design works, but needs a little reinforcement to make it
viable for the long haul. I’ll probably add plates to strengthen it and maybe
try sandwiching the plates the track sits on using the upright Technic beam
method Scott mentioned.
More Images
The next step is to do a Bricklink purchase to get the pieces for the 128-stud
bridge. The scaling from 92-studs to 128-studs shouldn’t be a big deal. This
bridge held the pictured engine and three hopper cars with no noticeable
deflection. The cars weren’t moving though, so I imagine I will have to
reinforce it more to deal with the vibration. I don’t want it crashing down in
the middle of a show. Oh the horror! The Minifig carnage! Minifig bodies
everywhere screaming for help as they are trapped inside a burning Santa Fe
dining car. Yeah...not a pretty sight.
Any thoughts on what I have so far? I’d really like to try one of those cool
cable-stayed bridges sometime, but I’ll need to get a closer look at how the
cables are held in place.
Also, I just want to thank everyone for all the great information and
enthusiasm. All of you are helping push me to do things I never dreamed I would
do with LEGO. All of your creations are an inspiration to Stacy and I and we
are so glad we’re part of such a cool group of people. In short...AFoL’s rock.
Thanks and Play Well!
-Dave
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In lugnet.trains, Ted Michon wrote:
| |
In lugnet.trains, Mike Gallagher wrote:
| |
,,
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.
.. Mike Gallagher
|
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 “cables” support the weight. We quickly determined that it was
easier to make the cables look cosmetically correct using bungee material (to
take up slack), but this proved impractical for supporting the thin deck. So
we added a truss under the deck so that even with twin heavy trains at random
locations we don’t get much deflection. Seems to work.
My next goal is a 384 stud (20 foot) suspension bridge with a 192 stud (10
foot) middle section using real cable. The biggest problem I see is anchoring
the ends (cable stayed bridges have their advantages!).
-Ted
|
Ted,
Sorry, I can not stand it anymore. A 48 stud baseplate is 15” and a fraction.
Two at 96 studs would be 30” and a fraction. Four at 192 studs would be 5 feet
and a fraction. Therefore 384 studs would be ten feet 3/4 of an inch.
Bruce
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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
|
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
mike
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In lugnet.trains, Bruce S. Chamberlain wrote:
| |
In lugnet.trains, Ted Michon wrote:
| |
In lugnet.trains, Mike Gallagher wrote:
| |
,,
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.
.. Mike Gallagher
|
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 “cables” support the weight. We quickly determined that it was
easier to make the cables look cosmetically correct using bungee material
(to take up slack), but this proved impractical for supporting the thin
deck. So we added a truss under the deck so that even with twin heavy trains
at random locations we don’t get much deflection. Seems to work.
My next goal is a 384 stud (20 foot) suspension bridge with a 192 stud (10
foot) middle section using real cable. The biggest problem I see is
anchoring the ends (cable stayed bridges have their advantages!).
-Ted
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Ted,
Sorry, I can not stand it anymore. A 48 stud baseplate is 15” and a fraction.
Two at 96 studs would be 30” and a fraction. Four at 192 studs would be 5
feet and a fraction. Therefore 384 studs would be ten feet 3/4 of an inch.
Bruce
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Aww, c’mon Bruce. All guys like to exaggerate the length of their LEGO bridges
when telling others about them. Especially when talking with the ladies. ;-)
Sorry Ted...Bruce kinda set me up for this one in a round-about way. :-)
-Dave
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In lugnet.trains, Bruce S. Chamberlain wrote:
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Sorry, I can not stand it anymore. A 48 stud baseplate is 15” and a fraction.
Two at 96 studs would be 30” and a fraction. Four at 192 studs would be 5
feet and a fraction. Therefore 384 studs would be ten feet 3/4 of an inch.
Bruce
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Bruce-
You are quite right, but my error is in studs, not feet. (I had an
in-the-back-of-my-mind-something’s-not-quite-right feeling even as I wrote the
post(s). I think the problem was that I knew that each single tower section was
192 studs long but in the picture we show two linked end to end for 384 studs. I
listed the stud length for 1 section and the foot length for 2 and it was all
downhill from there...)
Anyway:
The twin tower cable stayed bridge pictured is 384 studs (10 feet) long with a
192 stud (5 foot) middle span. We often set it on twin 60 inch tables.
The arch bridge is 288 studs long (7.5 feet).
The under and over truss bridges pictured are 192 studs (5 feet) long.
My pie in the sky suspension bridge would be 768 studs (20 feet) long with a 384
stud (10 foot) middle span.
-Ted
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In lugnet.trains, Dave Sterling wrote:
| |
..
Any thoughts on what I have so far? I’d really like to try one of those cool
cable-stayed bridges sometime, but I’ll need to get a closer look at how the
cables are held in place.
..
-Dave
|
Dave-
If you want your truss construction to actually support the bridge, you should
convert your trapezoids into triangles (i.e., break them up by adding verticals
in the middle). (Actually, the way many of us do this still makes trapezoids,
but one of the horizontal sections is so small that it’s effectively a
triangle.) The best way to make the triangles is to use length ratios 3:4:5 or
5:12:13 so they come out exactly in studs.
With regard to the “cable” in our cable stayed bridges, we just used bungee cord
(from Jo Ann Fabrics, which appears to be identical to the stuff that came with
LEGO Bungee Blasters a few years ago). In the towers, we just run through the
holes in Technic plates. At the deck, we run it through a piece of stiff LEGO
tubing, then a 1x1 cone, then a small Technic connector from the cone to an axle
hole, and wedge between the axle and axle hole and into the deck through a hole
in the side of a Technic brick.
-Ted
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|
| |
In lugnet.trains, Ted Michon wrote:
| |
In lugnet.trains, Dave Sterling wrote:
| |
..
Any thoughts on what I have so far? I’d really like to try one of those
cool cable-stayed bridges sometime, but I’ll need to get a closer look at
how the cables are held in place.
..
-Dave
|
Dave-
If you want your truss construction to actually support the bridge, you
should convert your trapezoids into triangles (i.e., break them up by adding
verticals in the middle). (Actually, the way many of us do this still makes
trapezoids, but one of the horizontal sections is so small that it’s
effectively a triangle.) The best way to make the triangles is to use length
ratios 3:4:5 or 5:12:13 so they come out exactly in studs.
-Ted
|
Yeah, after I built this I realized that I had the technic pins at the top too
far apart and should move them each in slightly to form a triangle. Right now
the track and track bed are supporting most of the load I think. I pulled out
my old Engineering Mechanics:Statics book today and started looking at the
chapter on trusses again. Haven’t looked at that chapter in about 6 years. :-)
I’ve got a bunch of technic bricks, pins, and beams on the way from various
Bricklink stores. Once those arrive next week I am going to start again.
Thanks for the tip on triangle sizes. I’ll have to keep that in mind when
designing my new bridge.
-Dave
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|
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In lugnet.trains, Dave Sterling wrote:
| |
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.
|
This bridge had a main
span of 96 studs, and could have been more if I had more room on the end to
attach the main cables further from the base of the tower. It could also be
doubled in length by building the same from the other end. The only downside is
that it needs a stable footing to attach the main cables - mine were attached to
the module base (MDF).
ROSCO
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I’ve found the deck can be pretty insubstantial; even in minifig scale, the
truss carries the weight.
The Notre Dame Bridge is about 320 studs long and has been up for over a year
now:
At least, I have heard no news of its collapse. It can take quite a bit of
weight. Many thanks to TJ Avery’s fantastic lbridge design spreadsheet
available at texbrick.com. There are spreadsheets for
both arch and straight trusses.
The “cables” are actually sandwiches of three layers of 1x plate built off the
end of each vertical member of the truss. They tie directly into the business
part of the underside:
The beams supporting the deck consist of sandwiches of three layers of plate,
mostly 2x8. The stacks of 1x3 and 1x4 bricks were included only for show. The
deck floats on top of the support beams. I think it’s a sandwich of two layers
of plate. The deck could easily be replaced with track that would need only a
minimum of reinforcement.
Hope this helps!
-Teddy
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|
| |
In lugnet.trains, Ted Michon wrote:
| |
In lugnet.trains, Dave Sterling wrote:
| |
..
Any thoughts on what I have so far? I’d really like to try one of those
cool cable-stayed bridges sometime, but I’ll need to get a closer look at
how the cables are held in place.
..
-Dave
|
Dave-
If you want your truss construction to actually support the bridge, you
should convert your trapezoids into triangles (i.e., break them up by adding
verticals in the middle). (Actually, the way many of us do this still makes
trapezoids, but one of the horizontal sections is so small that it’s
effectively a triangle.) The best way to make the triangles is to use length
ratios 3:4:5 or 5:12:13 so they come out exactly in studs.
-Ted
|
Ted:
Here’s V2.0 of my 92-stud bridge. I added the vertical bracing and it made a
HUGE difference in both the stability of the deck and the lateral stability of
the actual truss structure.
More Pictures
Now I just have to wait for my load-o-technic parts to arrive and I’m off to the
races. :-) One other thing. How much clearance should I have track to top of
the bridge? I was thinking 20 studs at first, but maybe I need more? I know it
fits all my rolling stock, but what if someone shows up with a bigger train and
wants to run it on my layout? Is there a “standard” bridge height most clubs
use?
Thanks,
Dave
|
|
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In lugnet.trains, Dave Sterling wrote:
| |
.. • How much clearance should I have track to
top of the bridge? I was thinking 20 studs at first, but maybe I need more?
I know it fits all my rolling stock, but what if someone shows up with a
bigger train and wants to run it on my layout? Is there a “standard” bridge
height most clubs use?
Thanks,
Dave
|
At work they like to quote the statement “Standards are great. That’s why we
have so many of them.”
Standard height is whatever you and whomever you interoperate with agree on. At
SCLTC, standard height is 14 bricks, measured from the top of a baseplate placed
on the table and includes the 1 plate we use to raise the track above the
baseplate (so we can use tiles under curve tracks) plus the height of the trails
themselves.)
We rarely get in trouble over lack of vertical clearance. A much bigger problem
is clearance around curves, which can bite you in unanticipated places. For
example, your bridge may offer great clearance for rolling stock that approaches
it on straight track, but not make it if it goes direct to curve track.
-Ted
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