4 votes

Dietzenbach Bottom Bridge


Elevation From West

Photo by Joe Elliott, Summer 1995, for HAER

View photos at Library of Congress

BH Photo #122740


This single-span truss crosses the Turkey River at the northern edge of Fayette County, in Section 3 of Auburn Township. Known locally as the Mill Race Bridge, presumably for its proximity to a riverside mill, the structure is configured as a six-panel Warren truss with pinned connections. The existing concrete abutments are evidently replacements of an earlier substructure. Although county records are somewhat sketchy, the Mill Race Bridge appears to have been erected n 1890. In January of that year the county board of supervisors received a citizens' petition for a permanent bridge at this location. The petition was referred, along with six others, to a committee of the whole, after which a contract was awarded to build the bridge. Fayette County had dealt almost exclusively with Horace E. Horton, a brilliant civil engineer from Minneapolis, for its wagon bridges in the 1880s. When Horton moved to the Chicago Bridge and Iron Company in the late 1880s, he brought the county with him as a client, and the latter firm was largely responsible for the county's bridges in the 1890s. The Mill Race Bridge was probably fabricated and erected by Chicago B&I for the county in 1890. Other than the subsequent replacement of its substructure, it remains in essentially unaltered condition today. The Pratt and Warren truss configurations were both developed in the 1840s, but it was the Pratt that received the most widespread use in the late 19th century. The reasons for this probably relate to the versatility of the pin-connected Pratt for different span lengths and its easier erection using timber falseworks. Relatively few pinned Warren trusses were ever built in Iowa and only a handful remains in use today. The Mill Race Bridge is distinguished as a well-preserved example of this uncommon 19th century truss type [adapted from Fraser 1992].


Warren through truss bridge over Turkey River on Pheasant Road near St. Lucas
Fayette County, Iowa
Replaced by new bridge; old structure still standing
Built 1891; Relocated here 1926; Replaced 2004 but left standing
- Chicago Bridge & Iron Co. of Chicago, Illinois
- Horace E. Horton of Rochester, Minnesota (Design)
"The Dietzenbach Bottom Bridge is an excellent example of the now rare late nineteenth century pin-connected, wrought-iron Warren truss. It seems to be the work of the creative and well-known engineer Horace Horton, the founder of the Chicago Bridge & Iron Company. While the bridge has been moved from its original location, both sites show the transportation roles played by bridges in Iowa.

"The Dietzenbach Bottom Bridge stands as an important example of the pin-connected wrought-iron Warren truss."

Leslie Pitner, August 1995, for HAER

Span length: 120.0 ft.
Total length: 120.0 ft.
Deck width: 16.0 ft.
Posted to the National Register of Historic Places on June 12, 1998
Also called
Turkey River Bridge
Mill Race Bridge
Old Elgin Creamery Bridge
Approximate latitude, longitude
+43.07748, -91.88908   (decimal degrees)
43°04'39" N, 91°53'21" W   (degrees°minutes'seconds")
Approximate UTM coordinates
15/590436/4770017 (zone/easting/northing)
Quadrangle map:
Saint Lucas
Inventory numbers
NRHP 98000784 (National Register of Historic Places reference number)
IA 153120 (Iowa bridge number)
BH 37325 (Bridgehunter.com ID)

Update Log 

  • September 3, 2021: Updated by Nathan Holth: Merged NBI Data
  • September 2, 2011: Updated by Luke Harden: removed year lost as it is clearly extant
  • September 2, 2011: New photos from Jason Smith
  • June 22, 2011: Updated by Jason Smith: Bridge was made functionally obsolete by a new bridge but remains intact
  • August 28, 2008: Added by J.R. Manning



Dietzenbach Bottom Bridge
Posted June 25, 2011, by Tony Dillon (spansaver [at] hotmail [dot] com)

This one has riveted connections on the upper chord.......and pin connections on the lower chord.

How unique is that!