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Thread: how to build a long arch bridge?

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    Default Re:how to build a long arch bridge?

    I would take a look here http://www.blackbearcc.com/index.htm and maybe you can get some ideas.

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    Default Re:how to build a long arch bridge?

    thanks for the help ejsneonss. i checked that site before. and just found out that they sell supplies separately. before i though they just sold kits.
    the styrene seems good. i have a question though. the styrene at the black bear site is sold in sheets or strips?

    i probably wont buy it there though. theres an art store about an hour subway ride from my house that sells them. what thicknesses do you recommend?
    Those who would give up essential liberty to purchase a little temporary safety deserve neither liberty nor safety. - Benjamin Franklin.

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    Default Re:how to build a long arch bridge?

    Pooka,

    There's a Kalmbach book on Bridges, although I don't recall the exact title. You may want to take a look at it. Also, there's an engineering "project" / contest that's always ongoing for building the 'strongest' bridge out of a certain amount of material.

    Now, I'm not familiar with the Hellgate bridge, so my answer isn't going to address that aspect. Rather, I'm going to discuss the general issue of an arch bridge.

    Long span arch bridges today are made of either steel, or reinforced concrete. A steel bridge will require a substantial amount of work to model, as all the various structural elements are visible. On the other hand, you can do a concrete bridge with a lot less trouble. Simply draw out the shape you want, then cut two pieces of 6mm Baltic Birch plywood into the shape, laminate them to both sides of some foam, and paint. Voila, a very strong, fairly light bridge. You could make it even lighter, and still plenty strong, by using 3mm Baltic Birch or 1/8" luan plywood, and just use a thicker foam. You can actually get the foam up to 4" thick fairly easily, and even thicker pieces are available from theater supply houses (what do you think they make those chairs that are always busting over people's heads out of, eh?) and dock manufacturers.

    You can detail the bridge however you like down the road, but you basic bridge will be ready to go for about $10. Actual costs will be higher because you'll likely have a fair amount of material left over, but you can use the leftovers for other projects. Once you have an initial bridge in place, with a "solid arch", you can start monkeying around with pierced arches. The reasons real bridges are built with pierced arches (less bridge to hold up = more carrying capacity) really don't matter for us, but aesthetically, a bridge that looks more like a 500' long real bridge will look better.

    Check out www.bridgepix.com for some inspiration
    Heart of flame, blood of steam, sinews of steel, the iron dragon thundered across the realms, throwing down tyrants and slaughtering despots, until finally, at World's End, it paused in thought. Gazing across the void, it sounded a*triumphant blast, befor

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    Default Re:how to build a long arch bridge?

    the type i want to model has the arch going over the deck ( the bridge in sidney, australia is also a good example) i dont think concrete would be a good choice for several reasons:
    1. i like to build stuff so i dont mind all the work that a steel bridge will take
    2. im modeling the 20s-30s and i dont think concrete arch bridges were in use then.
    3. the bridge will not be in use right away since one of the shelfs will be begun after the first is pretty much completed (and thats still in the design stages) so i have plenty of time to build it
    4. i hate the look of concrete on buildings....so modern...and simple, its disgusting. :roll:

    edit:
    heres hellgate bridge i was talking about
    http://www.bridgeandtunnelclub.com/b...20hellgate.jpg

    and wow, someone even decided to make a 20 foot long model of it
    http://www.hirailers.com/modular_layouts.htm
    its the first pic down, cant see much but you can see the stone abutements and part of the arch with a Santa Fe F unit rolling across
    Those who would give up essential liberty to purchase a little temporary safety deserve neither liberty nor safety. - Benjamin Franklin.

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    Default Re:how to build a long arch bridge?

    Have you looked at Evergreen Styrene or Plastistruct Products, I know that Plastistruct makes a wide variety and sizes of steel girders. I don't think that they have a Web Site but are generally available at most hobby shops. They come in Black, Grey, and White.
    Evergreen also has some girders. Their Web Site is: http://www.evergreenscalemodels.com/

    They have a very good soft cover book out on modeling with their product, it is worth picking up as it is full of hints and tips.
    Even if these don't have the exact style that you are looking for, the wide variety of shapes will usually allow you to combine several styles/designs to create a close facsimile. It is easy to work with and many of the shapes can be bent without distortion.

    Also one of the German companies has a very modern steel arch bridge, think that it might be Kibri(?) Can't quite remember the name. I bought a double kit at a swap meet about 2 years ago for $10.00. Nice Bridge.

    Just thought of one other thing, check the local public library for books on bridge construction, steel girder brdiges, and model railroad bridges. Here in MN, I found quite a good selection of drawings and pics.

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    Default Re:how to build a long arch bridge?

    Here is another idea, if you don't mind kit bashing. Go to: www.eurorailhobbies.com/
    Then under product lines, select Faller, then over on the right there is a box that says "Other Faller Products", click on th arrows and scroll down to Tunnels & Bridges(?). They have quite selection of steel bridges. Not exactly like what you describe, but I bet that they could easily be the start of a good kit-bash. Appears that they are available in the US at decent prices.

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    Default Re:how to build a long arch bridge?

    hey tobyboy, yea i know about the faller bridges, theyre pretty cool but i would prefer to just scratch build.
    i decided to go with midwest's styrene beams and girders
    http://www2.towerhobbies.com/cgi-bin...&V=MID
    now to draw up the plans and buy the materials.
    once i start construction i will post pics and stuff in this thread
    Those who would give up essential liberty to purchase a little temporary safety deserve neither liberty nor safety. - Benjamin Franklin.

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    Default Re:how to build a long arch bridge?

    I saw where you indicated that you prefer a bridge with the arch over the roadbed.

    However, I thought you might be interested in looking at a very picturesque under-arch bridge. This page has 44 thumbnail pics of the Perrine bridge in Twin Falls, Idaho:

    http://www.bridgepix.com/listing.php...fce18784a5458e

    I will be modeling this bridge for my layout.
    (The voices I hear in my head may not be real, but sometimes they come up with a good idea.)

    Have fun.

    Moose

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    Default Re:how to build a long arch bridge?

    very cool MooseID. I saw pictures of it before. dont you think it may be a bit big to model? how big would a proper scale model of that come out to be?

    another thing i was thinking of modeling is sort of an arch bridge exept the middle of the arch is taken out and cables are run from the two remaining parts on each side to the deck to hold it. its kind of like a suspension bridge i guess exept the columns are way on the ends of the bridge and the tops are leaning in towards the middle. it may sound impossible but i have tried it in this game called bridge construction set and it worked very well, a bit wobly but i was very limited on funds so i couldnt make too many supports in the columns. its a really cool design, perhaps a bit impractical but very nice looking and will definately attract attention.
    Those who would give up essential liberty to purchase a little temporary safety deserve neither liberty nor safety. - Benjamin Franklin.

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    Default Re:how to build a long arch bridge?

    I am not sure...

    But, I will get the dimensions.
    (The voices I hear in my head may not be real, but sometimes they come up with a good idea.)

    Have fun.

    Moose

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    Default Re:how to build a long arch bridge?

    The Perrine Bridge in Twin Falls, Idaho.

    The span is right at 1500 feet.

    The heighth above the Snake River to the top of the roadbed is 486 feet.

    If built to 1:350 scale it would be 51 inches long and 16 inches high.

    The 1:350 scale for something like this isn't too difficult.

    Most of the structure could be put together with Z-Scale styrene or brass. Some of the finer substructure could probably be done with fine wire.

    (Edited By Moose.....OOPS, sorry)
    (The voices I hear in my head may not be real, but sometimes they come up with a good idea.)

    Have fun.

    Moose

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    Default Re:how to build a long arch bridge?

    Um, Moose...you sure 'bout those numbers?
    (EDIT: Original Post corrected. My corrections removed)

    If built to N-scale, that bridge would be 9.375 feet long and 3.038 feet tall.
    Hellgate bridge in NY only has a span of 977 feet...in 1/350, thats 2.791 feet, or in N-scale, 6.106 feet.

    Cheers,
    AR
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    Default Re:how to build a long arch bridge?

    Um, Moose...you sure 'bout those numbers?

    uh oh.......
    knew that was comin'..... 8)
    one thing i learn every day is that i don't know very much......

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    Default Re:how to build a long arch bridge?

    OK, I admit it. I am not totally perfect.

    1500 / 350 = 4.2857 feet

    4.2857 X 12 = 51.428 inches

    Where did I go wrong?

    (I fixed the other post...... sorry. Thanks for calling it to my attention)
    (The voices I hear in my head may not be real, but sometimes they come up with a good idea.)

    Have fun.

    Moose

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    Default Re:how to build a long arch bridge?

    Quote Originally Posted by "kebmo"
    Um, Moose...you sure 'bout those numbers?
    uh oh.......
    knew that was comin'..... 8)
    But of course
    You wouldn't want some poor guy building a 51-foot bridge, would you? Actually, I'd like to see it too, but thats not the point :twisted:

    Moose,
    I got your PM. Since you've changed your post, I'll change mine since it no longer makes sense.

    Cheers
    AR
    Siderod (II)
    Andrew Reid
    * * *

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    Default Re:how to build a long arch bridge?

    well i made a basic sketch of the bridge and got some materials. lucky me theres an art store not far from my house that sells midwest styrene girders.
    Those who would give up essential liberty to purchase a little temporary safety deserve neither liberty nor safety. - Benjamin Franklin.

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    Default Re:how to build a long arch bridge?

    well i made a basic sketch of the bridge and got some materials. lucky me theres an art store not far from my house that sells midwest styrene girders.
    Those who would give up essential liberty to purchase a little temporary safety deserve neither liberty nor safety. - Benjamin Franklin.

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    Default Re:how to build a long arch bridge?

    hey guys

    the bridge will be put off for a while until i have both shelves up and the track leading to it set up. id rather fit the bridge into the layout than try to fit the layout around the bridge if that makes sense.

    for now ill build a smaller bridge diorama which wont be deigned for the layout, but may be put in sometime in the future. mainly im just building it to add to my school portfolio. i go to an architecture high school and we need to present like 12 or so works we did over the year.....and im reeeaaaly lacking.

    edit: forgot to say, ill post pictures of the bridge diorama here.
    Those who would give up essential liberty to purchase a little temporary safety deserve neither liberty nor safety. - Benjamin Franklin.

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    Default Long Arch Bridge

    Why not save yourself alot of scratchbuilding and use bridge made for a larger scale? An HO scale single track bridge can suffice for an N scale double track bridge. Since most models are selectively compressed anyway, using an even an O scale bridge, might result in a more prototypically-sized N scale model. See photos of the O Scale MTH Hellgate bridge model.

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    Default Re:how to build a long arch bridge?

    I'd like to see more of that 0 scale Hell Gate bridge. At 20 ft. long, thats pretty impressive.
    Jim

    As you grow older, three things happen. First thing is your memory goes, and I can't remember the other two.

    My Flickr photo stream ...https://www.flickr.com/photos/schuylkillvalleyrr/

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