2 votes

Herring Viaduct


Photo taken by Jason Smith


BH Photo #213295


Cantilevered deck truss bridge over Des Moines River and B Avenue on Kenyon Road in Ft. Dodge
Fort Dodge, Webster County, Iowa
Open to traffic
Future prospects
Built 1935; rehabilitated 1977
- Iowa State Highway Commission of Ames, Iowa (Design)
Cantilevered Warren deck truss with sub-panels
Length of largest span: 136.2 ft.
Total length: 562.0 ft.
Deck width: 32.8 ft.
Also called
Kenyon Road Bridge
Approximate latitude, longitude
+42.49393, -94.18861   (decimal degrees)
42°29'38" N, 94°11'19" W   (degrees°minutes'seconds")
Approximate UTM coordinates
15/402326/4705303 (zone/easting/northing)
Quadrangle map:
Fort Dodge South
Average daily traffic (as of 2015)
Inventory numbers
IA 52081 (Iowa bridge number)
BH 49546 (Bridgehunter.com ID)
Inspection report (as of August 2017)
Overall condition: Fair
Superstructure condition rating: Satisfactory (6 out of 9)
Substructure condition rating: Fair (5 out of 9)
Deck condition rating: Good (7 out of 9)
Sufficiency rating: 60.2 (out of 100)
View more at BridgeReports.com

Update Log 

  • April 7, 2020: Updated by Luke: Doomed
  • June 4, 2015: Updated by Luke: Edited name to local name
  • March 27, 2013: Updated by Fmiser: added "catilevered" to design description
  • March 27, 2013: New photos from John Marvig
  • September 8, 2011: Updated by Jason Smith: The bridge is on Kenyon Road which also carries business route US 20


  • Jason Smith - flensburg [dot] bridgehunter [dot] av [at] googlemail [dot] com
  • Historicbridges.org - by Nathan Holth
  • John Marvig - marvigj27 [at] gmail [dot] com
  • Fmiser - fmiser [at] gmail [dot] com
  • Luke
  • IowaHighwayEnds - Info


Herring Viaduct
Posted April 8, 2020, by Mike Kerkau (mjkerkau [at] gmail [dot] com)

Sadly that seems to be a "bloody shirt" of choice even when the bridge they're concerned about is nothing like the I-35.

Here in Bay City, with two bascules sold to UBP (yes, *that* UBP) at the end of last year, the fear-urgency behind having a solution for some kind of repair/replacement work for them, at least on the Mayor's part, was a complete fear of having a collapse happen here.

Herring Viaduct
Posted April 8, 2020, by Clark Vance (cvance [at] dogmail [dot] com)

They sure love "Waving the bloody shirt" of the I-35 bridge. No one points at concrete trucks and screams "Danger".

Herring Viaduct
Posted April 7, 2020, by Luke
Herring Viaduct
Posted June 4, 2015, by Nathan Holth (webmaster [at] historicbridges [dot] org)

I think this may be continuous vs cantilevered. Its hard to see in the photos to confirm, but the reason is typically, aside from the usual presence of suspended span in a cantilever, a cantilever deck truss would typically not "bear" on the pier at the ends in the traditional sense of the word... what we typically see with a cantilever is that this area is in tension and the end is in fact anchored (often by eyebar chain embedded in the pier)... whereas I think this looks like its just a regular bearing sole plate/masonry plate... but again I can't actually see for sure. Here is an unusually obvious example of cantilever anchorage (Deception Pass Bridge) http://historicbridges.org/washington/deceptionpass/deceptio... although other bridges its not this obvious.

Kenyon Road Bridge
Posted March 27, 2013, by Fmiser (fmiser [at] gmail [dot] com)

I agree with Robert. The clue is the end of the span. And while Jason took some good pictures, none are titled or commented so I'll refer to John Marvig's photos.

"Second pier from west" and "Span" clearly show the arc is not at the end. In other words, the high strength, wide part of the web is above the bents. This is a characteristic of a cantilvered truss.

So I'm changing the design field.

Kenyon Road Bridge
Posted March 27, 2013, by Robert Elder (robertelder1 [at] gmail [dot] com)

I would classify this one as a cantilver deck truss.