2 votes

Rosedale Concrete Bowstring


Photo taken by J.P. in December 2009


BH Photo #150536



Concrete girder bridge over North Branch of Otter Creek on Rosedale Road
Parke County, Indiana
Open to traffic
Concrete curved chord through girder
Length of largest span: 49.5 ft.
Total length: 56.1 ft.
Deck width: 17.7 ft.
Eligible for the National Register of Historic Places
Approximate latitude, longitude
+39.61083, -87.13250   (decimal degrees)
39°36'39" N, 87°07'57" W   (degrees°minutes'seconds")
Approximate UTM coordinates
16/488625/4384573 (zone/easting/northing)
Quadrangle map:
Brazil West
Average daily traffic (as of 2016)
Inventory numbers
INNBI 6100017 (Indiana bridge number on the National Bridge Inventory)
BH 43723 (Bridgehunter.com ID)
Inspection report (as of April 2018)
Overall condition: Poor
Superstructure condition rating: Fair (5 out of 9)
Substructure condition rating: Poor (4 out of 9)
Deck condition rating: Satisfactory (6 out of 9)
Sufficiency rating: 50 (out of 100)
View more at BridgeReports.com

Update Log 

  • July 17, 2012: New photos from Steve Conro
  • May 12, 2010: New photos from Anthony Dillon
  • December 8, 2009: Added by J.P.



Rosedale Concrete Bowstring
Posted December 9, 2009, by Michael Goff (michael [dot] goff [at] odot [dot] state [dot] or [dot] us)

These "bowstring" girders are quite interesting structures. I would love to see a set of plans for one of these girders to see how the load is carried. It would be neat to see if the girders are designed as an enclosed tied arch or just a girder with a thickened middle section.

Whether the arched portion is an efficient use of material or an enclosed tied arch they are still great finds. The bridges have graceful designs that could have appeared very blocky had the girders been designed with out the arched portions.

Rosedale Concrete Bowstring
Posted December 9, 2009, by J.P.

I actually found these on the indiana historic bridge registry. i was amazed. theres actually a couple more we didn't get to but plan to go back and get. We were impressed when we finally got to see one.

Rosedale Concrete Bowstring
Posted December 9, 2009, by Nathan Holth (form3 [at] historicbridges [dot] org)

An amazing find! I was not aware of the presence of these bridges in Indiana. Even if not recognized in the Historic Bridge Inventory, these bridges should be considered extremely rare and historically and technologically significant.

It is deeply unfortunate that these bridges have not received the attention that Parke County's covered bridges have.

The technical structural type of the bridge is "concrete curved chord through girder" and they are typically called "concrete camelbacks" in Michigan, which is the undisputed capital of curved chord through girders. They drive the National Bridge Inventory nuts: I have seen them listed as girders, slabs, arches, and I see they are currently listed as stringers / bowstrings here. These discrepancies serve to indicate how exceedingly unusual and rare this structure type is.

By the way, in Michigan, the vast majority of our concrete girder bridges have an integral flooring system (slab) design and do not have visible floorbeams.

These Indiana girders remind me of Ohio's design for this bridge type, simple, yet graceful in shape.

Rosedale Concrete Bowstring
Posted December 8, 2009, by J.P.

Parke County has the only arched girders in Indiana. The arch was probably introduced to provide unusual girder depth at center for this extraordinarily long span and to eliminate redundant material at the ends. In addition, only a minority of concrete through girders use a slab rather than floor beams to support the roadway. The girders are also nicely decorated.

Architectural Description: The concrete through girder has a pair of large beams which flank the roadway and whose reinforcing rods are interlocked with those of either floor beams or of a slab deck. Because of its greater rigidity, the through girder can be extended beyond the T-beam's ordinary span length. In most cases, though, it has been preferred over the T-beam only when headroom is critical, i.e; where the roadway is so close to stream level that girders, which carry some of their load above the roadway, provide greater assurance against obstructing the watercourse.