Among all of the bridges on this site, the longest pin-connected Pratt truss I could find is actually in Montana. It has a main span of 220 ft. with 11 panels:
Yeah....that's my bad for not mentioning the approach spans on the bridge when talking about the length. I knew the through truss had to be pushing the 200 foot range however.
Wish somebody would remove the graffiti underneith this. "F- bombs" are really innappropriate.
Okay, that makes sense. This is still an incredible bridge though!
It looks like the bridge you referenced still holds the record: the 231' length includes the approaches on this one. It looks like the main span is about 190 feet.
If the 231 foot length of this bridge is indeed accurate, then it becomes the longest single-span Pratt truss of which I am personally aware. It has dethroned this one:
A discussion of unusually long Pratt trusses can be found in the comments section of this same page.
Wow! Nice pics, Matt! # 6 is definitely a "Beauty Shot". I'll have to get up there to see it.
In response to the comment regarding Photo #7, that stone abutment is supporting one of the timber approach spans, while the main truss structure is supported by very large concrete-filled steel caissons. Frost could very well become an issue for the stone abutments, but I am uncertain how much has been done with them since the bridge's construction 125 years ago. Up close and personal, the abutments appear to be sound, but hopefully there are those keeping an eye out for just such possibilities.
This is another example of a builder pushing the conventional limits of a particular truss type. Just why Morse went with a Pratt here when a Whipple would seem to be more appropriate is uncertain. The counties may have specified the more economical Pratt, which may have even been designed by a local engineer. The truss depth looks to be equal to that of a Whipple. What really amazes me is the lack of any sway bracing between the trusses, just simple struts and lateral bracing overhead. The inside clearance is impressive, but is basically moot considering the limitations of the portal bracing.
It always fascinates me to try and reason just why a particular span was built a certain way. Perhaps there are records to be found that would answer the questions, but sometimes it is fun to just ponder for a while.
The bottom line remains the same...... This is truly one of Morse Bridge Company's finest extant spans, a gem that has stood proudly for 125 years.
Re: photo # 7
It appears that the mortar on the field-stone bridge abutments could use some re-pointing. Otherwise, frost could loosen the stones and threaten the structure.
It is an incredible structure, and appears to be well taken care of. Fellow pontist Jason Smith and I went out there today and took many pictures; I'm quite sure that he will post the pictures he took of the bridge as well. I even fell through the ice and into the Crow River trying to get elevation shots! Hahahahaha!!! Only one leg, fortunately!
This is a wonderful span with extremely tall and wide panels. Would be nice to see this one rehabilitated in the near future!