# Black River abandoned bridge or other skewed truss bridge



## bluenavigator (Aug 30, 2015)

My next scratch project is skewed truss bridge. I will need it for third bridge on my layout. 

I am considering this abandoned bridge but the picture is pretty difficult to figure out how it was built. 

Here is the coordinates of where the abandoned bridge being located in Poplar Bluff, MO.

36°45'40.6"N 90°23'11.1"W 

Map link

It seems that there is not many pictures of this bridge. So far, I found two... Not enough to figure the dimensions. 



















Anyone know another skewed truss bridge? I am still browsing the images on Google. The decision is not final yet.


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## bluenavigator (Aug 30, 2015)

As I am still browsing around and I came across this warren truss bridge, which seems to good project for me to start with.










As it does show where the old rail plates used to be mounted, it is clear marked as starting dimension. The question is the dimension of the plate. Anyone know the actual standard plate?

Now I just realized that it is there already. As we know that it is 4 ft 8 1⁄2 in, I would use one side of both rails. So inside dimension of the truss would be around 14' 5"?


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## J.C. (Dec 24, 2016)

try this link http://www.loc.gov/pictures/collection/hh/item/ut0117/ or this one http://www.loc.gov/pictures/collection/hh/item/mo0162/ this is one I plan on trying http://www.loc.gov/pictures/collection/hh/item/md0741/ you could also use diminutions off a highway bridge as designs were same in a lot of them.


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## Big Ed (Jun 16, 2009)

You guys ever come across this site?
http://bridgehunter.com/

Lots of Bridges and pictures there.
Maybe something in there will help you. :smokin:


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## bluenavigator (Aug 30, 2015)

Big Ed said:


> You guys ever come across this site?
> http://bridgehunter.com/
> 
> Lots of Bridges and pictures there.
> Maybe something in there will help you. :smokin:


Yea, been browsing over there, too. Actually, I went to this location when I was doing noodling in the water and saw the bridge. Never thought that I would come across this site for this specific bridge. That bridge is only 15 minutes drive from my home. Will make time to drive over there and do a bit of walking.
http://bridgehunter.com/tx/williamson/bh49565/

In fact, when I was doing noodling under the bridge, there is a part of truss in the water but I could not see since the water is murky. It does not feel like that it was rusted at all but I could tell that it is a bit long... maybe 10 feet as far as I could tell.


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## J.C. (Dec 24, 2016)

the advantage of the library of congress(LOC) over bridge hunters is the LOC has measured drawings with some of there bridges but not all.


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## Lemonhawk (Sep 24, 2013)

The CV truss  bridge can be built skewed. www.cvmw.com. Also their Plate girder bridge.


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## bluenavigator (Aug 30, 2015)

Finally, I made the trip to the active bridge. Oh boy, it is sooo HOT! I dunno how hot it was at the bridge. It was 94°F when I arrived at the parking nearby. 

I went to the one that I mentioned in previous post - San Gabriel River Bridge

The river's water level is much higher than the last time that I swam in there. I guess that was due to the previous heavy rain from last weekend. Oh boy, I wish that it is still raining. That would cool me off but it might cause the trail to be more slippery. 

I took several necessary measurements at where I could get to. The only thing that I could not do is to measure the total height. It is quite high from where I had stood at the beginning of the bridge. Also, I took enough photos. Here are some of them below. 

Under the bridge from the side









Additional girder plate bridge - after the truss bridge









Just under the bridge - able to see the rails 









Front of the brigde - you can see the winding measure tape on right side.









It is possible that I will go back there again, to take another measurements that I might need. Will wait until the rainy day, then I am good to go there.


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## CTValleyRR (Jul 26, 2014)

Measuring height in something like that is an exercise in high school math. Simply include an object of known length (like a 6' section of 2x4, which you can even mark with red lines at known intervals).

This allows you to make a pretty good guess at the length of anything at the same distance from the lens, and by using ratios, you can find the lengths of similar objects in the distance.

Say you have an upright which is 1.67x the length of your 2x4. So it's 10 feet tall. The corresponding upright at the far end of the structure is ALSO 10' high. If it appears half as big, then you can use that relationship to determine the size of everything at that end of the structure. And so on.


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## bluenavigator (Aug 30, 2015)

CTValleyRR said:


> Measuring height in something like that is an exercise in high school math. Simply include an object of known length (like a 6' section of 2x4, which you can even mark with red lines at known intervals).
> 
> This allows you to make a pretty good guess at the length of anything at the same distance from the lens, and by using ratios, you can find the lengths of similar objects in the distance.
> 
> Say you have an upright which is 1.67x the length of your 2x4. So it's 10 feet tall. The corresponding upright at the far end of the structure is ALSO 10' high. If it appears half as big, then you can use that relationship to determine the size of everything at that end of the structure. And so on.


That is true. My boy said that I should had used my smartphone to check the angle on the truss. I didn't realize that I am able to do that since I had used such application to check the degree on different task. I just forgot about that. As I said, I will go back there again and do other measurements that I had missed. Just not anytime soon since it is too hot outside. I am hoping for a good rainy day.

Also, I had been checking these old drafting sheets. Turned out that there are some measurements that are not available, making it more difficult for me to figure the actual measurement. For example, there are some 13" x 1' - 0 1/2" x 1/4" plates on the trusses but didn't show where they were to be placed on the truss. Pretty much anywhere to put them, which does not make any sense. Also, noticed the dimensions as stated recently, ( 13" x 1' - 0 1/2" x 1/4'), they were mixed. For example, they used 13" instead of 1' - 1" while they bothered to do that on the second part ( 1' - 0 1/2"). I just find it quite interesting on how they write down the measurement. Also, I noticed that they didn't bother to state measurement between rivets. It is possible that they are using standardized distance between rivets? Also, there is no known measurement end to end of the truss or specific C beam. Maybe it is there... I am seeing this strange definition of the measurement - 2 [s 9" @ 13 1/4#. The pound symbol threw me off. I am thinking that it means 13 1/4 lbs per ft, which is measurement for stress capacity. What it tells is that it is 2 of C beams, side by side and is 9" height. Nothing for width or length. Length should not be a problem at all. Only width dimension is missing. I am referring to the drawing below.









Here is the link for such drawings - link

Of course, today, everything has to be noted. Otherwise, they would not be approved for being built, right?


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## J.C. (Dec 24, 2016)

FYI almost any bridge design can be skewed 15 deg. without any design changes other than top and bottom cross members cut at that angle as per bridge engineering standards. also tichy has a assortment of rivet plates for building bridges here is link. https://www.tichytraingroup.com/Shop/tabid/91/c/ho_nbw--rivets/p/8216/Default.aspx


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