Deer Creek Bridge

That was my general thoughts as well. I have typically referred to these bridges as Pratts, mostly because I have doubted that a Warren could balance its own weight in just four panels.

In the past, my argument was you can call it whichever you want, in terms of visual layout it meets the definition of both Pratt and Warren. However, I was thinking tonight about the engineering design. If memory serves, the defining feature of a Warren truss is that diagonals alternate in stress from tension to compression, a fact most visible in pin-connected Warrens where diagonals switched between tension eyebar and built-up compression boxes. However, I believe the end diagonals at each end would be expected to be in tension. In other words both diagonals on this small truss are in tension. There are not enough panels to develop the tension/compression pattern of diagonals. A truss having all diagonals in tension is more like the definition of a Pratt. So now having considered that I feel that a bridge of this design is probably best considered a Pratt.

Thanks as always for tracking these bridges down.

I still don't know if the Bridgehunter community ever did arrive at a consensus of whether this type of bridge follows the Warren or Pratt configuration.

Several bridges packed into this area just N of Atchison