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DJ;

Very nice video, and excellent modeling! One weird thing though. Your model truss bridge has a supporting pier in the middle of the truss. This is not how bridges are normally built. The whole reason for using a truss is to span a wide gap between the supporting abutments, or piers. The truss is rigid enough to handle a longer span between supports than the plate girder bridge used as a shorter approach span in the rear of the prototype photo. Sometimes two successive trusses may have light frame members between the tops of the two trusses. I'm not sure of the reason for these, but they can look a bit like the bridge is one continuous truss. If there is a pier located between the ends of the two trusses, and under those light frame members, it could give the impression of a pier located "in the middle" of the "continuous truss."
I do know of one example of a prototype truss bridge that actually did have a support in the middle. In fact, I grew up near it. However, It was a swing bridge that could rotate 90 degrees, around that center support, to let ships get by. There would normally be no reason to support the middle area of a fixed truss bridge, only the two ends. Looking at the video of the prototype bridge, there are indeed several piers in the middle of the river, but each of those piers is supporting the end of a truss, or two ends of two trusses, not the middle.

Traction Fan 😊
 

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Discussion Starter #4
the original bridge was replaced, and i am having a tough time removing the pier, lol
 
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