# Has anyone built big bridges before?



## CapeCodSteam (Jan 2, 2008)

Greetings,

Here are a few sketches for bridges being worked on this season for the Setucket Creek & Far Fields Railway.










If anyone has experience with concrete esp, I look forward to hearing about it. The plan for the Viaduct is to create a form that can be used three times to bridge the span. Both bridges will be double main line


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## livesteam53 (Jan 4, 2008)

I did build a concrete arched like you drew many years ago. I don't have any pictures. Bridge was at the old house. I formed in out plywood and used Foam for the arches and then poured the concrete. 

This Steel bridge I built a few years ago. 

http://1stclass.mylargescale.com/livesteam53/New%20arched%20bridge%20008.jpg  

http://1stclass.mylargescale.com/li....jpg


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## toddalin (Jan 4, 2008)

I would make the via duct of "coated styrofoam." That would be quick and easy. You could do it in the shop and just put it in place when done, possibly in sections if its to be really big. If you are not in a hurry, watch to an article in _Garden Railways Magazine_ on a quick simple process to accomplish this using hydraulic cement for a _real_ waterproof finish.

I would make the metal structure out of brass rod simply because it's easy to work with and solder.


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## Jerry Barnes (Jan 2, 2008)

i used some outdoor blue foam board. Had PT lumber for the base, then screwed it over the wood. Scored lines in it for blocks and painted it with artist's acrylic colors. You can see it on my 
web site in some of the pix. It's a gray arched bridge. I made a metal one, it is also on my web site. Look under the projects button on the left side as you scroll down.


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## toddalin (Jan 4, 2008)

...


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## xo18thfa (Jan 2, 2008)

Check out what these guys did. The detail is tremendous.

http://www.mylargescale.com/Communi...spx#141659

Google Books has some old bridge engineering books that show the details


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## Richard Weatherby (Jan 3, 2008)

For some reason the above link came across as raw code. Try this one *BOLLMAN TRUSS BRIDGE*
If you do get to the thread on the Bollman Truss Bridge, Here is a link to the Drawings available. *HISTORIC DRAWINGS* 
A truly beautiful bridge.


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## Totalwrecker (Feb 26, 2009)

Thanks Richard, 
I've got several photos of Bollmans for future projects... this link will really help if I ever get motivated! lol 

John


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## SteveC (Jan 2, 2008)

Posted By Richard Weatherby on 05 Mar 2010 07:36 PM 
For some reason the above link came across as raw code. {snip...}[/i] Just a FYI, that's Because the link that Bob provided pointed to a specific posted reply (i.e. Default.aspx#141659), within a topic that has multiple pages based on Bob's 'Items Per Page' setting. If your 'Items Per Page' setting matches Bob's then the link will work, if not the you get the raw screen that you encountered Richard.


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## StanleyAmes (Jan 3, 2008)

For concrete bridges I recommend using Non Shrinking Grout avaiilable at Home Depot. It seems to last longer for Bridge Structures and is easy to cast. 

Stan Ames


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## Pete Thornton (Jan 2, 2008)

Kent, 

One of the tricks when pouring concrete into a form is to vibrate it to get the air bubbles out. I recall one guy used his rattling power tool, (forget whether it was a saber saw or a finish sander,) on the outside to get a smooth consistency.


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## Totalwrecker (Feb 26, 2009)

For casting I like CementAll, it's concrete repair mix and is also non shrinking and light in color. Stucco tints work well in it. 
All my tools are vibration free (I wish) ... I use a stick to tamp the pour and get it into the corners. Push the stick into the mix and using a rapid up and down motion I liqufy the cement and it flows out and fills the gaps and allows bubbles to rise. I cast my engine house several years ago and it's held up well. It was tinted to an adobe color and poured over a frame filled with pebbles. Even on a flat pour I used a stick to help it spread by vibrating the stick in the mix. No pebbles fell out. 

John


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## Daniel Peck (Mar 31, 2009)

I am working on a welded arch about 20 across and 6 ft high.


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