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Is a bridge this long even possible?

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  • Member since
    September 2003
  • 21,669 posts
Posted by Overmod on Tuesday, June 29, 2021 8:34 AM

Suspect a through girder bridge with 'center dump' would have transverse plate diaphragms for lateral reinforcement, basically like box construction.  Presumably there would be angled 'caps' on the top and bottom webs of the members to spill dumped material.

  • Member since
    March 2011
  • 1,950 posts
Posted by NVSRR on Tuesday, June 29, 2021 8:24 AM

Central Valley makes girder bridge lengths of 80 and 100' I do believe.    The picture looks like 100' segments based on the spacing of piers and height of the beams.  But not sure of the design. If that is a through center dump, then the design is different from a standard girder bridge,  girders have a lot of cross racing that would cause issues with a through deck dumping design.   Side dump standard girders are fine.  

most likely design is Ibeams under the rails with cross beams every 10 feet sandwiched between the tall girders on each side. Looks like a catwalk alongside  so most likely the beams are set so the rail is even with the top of the beams.

 

shane

A pessimist sees a dark tunnel

An optimist sees the light at the end of the tunnel

A realist sees a frieght train

An engineer sees three idiots standing on the tracks stairing blankly in space

  • Member since
    September 2003
  • 21,669 posts
Posted by Overmod on Tuesday, June 29, 2021 8:21 AM

One way these were made was in cast concrete -- in that part of the world Lehigh cement could be cheap.  See all the use the Lackawanna made of various forms (pun intended).

You could easily 'gin something up using a strip of something like wood molding, with wood supports, and just paint in the shuttering detail, spalling and reinforcement rust, etc. that characterize that kind of construction as it ages.   

  • Member since
    February 2012
  • From: Southington, CT
  • 106 posts
Is a bridge this long even possible?
Posted by mthobbies on Tuesday, June 29, 2021 8:07 AM

Hi everyone. As some of you know, I am making one half of my layout a zinc smelting waste dump.

As a result, I need to build a deck girder bridge for the entire length of the dump. Similar to the one shown in the picture below.

Conrail freight on the ex-CNJ passes New Jersey Zinc plant

The highline would be about 8ft long on my layout including a curve. Does anyone make girder sections in long lengths? (I'm talking longer than Atlas snap track long) I have scratchbuilt my own girder bridge before, but to build one this long from scratch would be way too time consuming and tedious. What's the most efficient and economical way to build such a long bridge?

Reccomendations for building really long bridges would be appreciated. Florida East Coast modelers speak up.

On second thought, I'm not even sure if that's actually a girder bridge. Maybe someone out there has expertise on these types of coal/highline dump bridges.

Thanks,

 

Matt

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