3 votes

Mackey Bridge



Photo Courtesy Iowa Department of Transportation.


BH Photo #192819


Crossing Squaw Creek some seven miles northeast of Ridgeport in the northeastern corner of Boone County, this concrete fixed Marsh arch dates to 1918. The Squaw Creek Bridge features slotted concrete guardrails with paneled concrete bulkheads and is supported by concrete abutments. The county supervisors awarded a construction contract to the Marsh Engineering Company to erect the structure for an undocumented amount of money. The Des Moines-based firm used a design created by James Marsh, a civil engineer and rainbow arch patent holder. Since its construction in 1918, the Squaw Creek Bridge continues to carry vehicular traffic in essentially unaltered condition. This medium-scale arch marks a noteworthy innovation in bridge design, an achievement engineered and patented by James Marsh in 1912. Marsh's design represented the hybridization of continuous concrete and segmental steel-arch designs, a radical departure from standard engineering practice. Concrete can withstand a nominal amount of tension. For this reason, most previous concrete arches--both reinforced and mass arches in filled and open spandrel configurations--were built with the arch below the deck, where the downward force of the deck could be carried in compression by the arch ribs and spandrel wall or columns. Marsh's suspended arch reversed this. His arches, of course, act in compression; but the hangers and floor beams carry the deck in tension. Furthermore, the novel treatment of the deck over sliding steel plates on the floor beams and the use of pin-connected, articulated steel hangers for the end panel points were devices more suited to steel construction than concrete. To make the concrete thus act against its nature, Marsh inserted large amounts of structural steel. His bridges may look like concrete spans, but the arch ribs and hangers carry such heavy and complicated reinforcing that they are, in reality, steel structures encased in concrete. Marsh designed his bridges with either tied (with the arches attached to the abutments at the floor beam level) or fixed (arches extending below the floor beams to the abutments) configurations. Aside from this, all of his rainbow arches were similar, varying only in span length, arch rise and number of hangers. Marsh's invention did not foretell a new direction in reinforced concrete design. The industry would later turn to other, simpler slab and beam configurations as it developed more sophisticated reinforcing techniques in the 1930s and 1940s. The rainbow arch did, however, denote one of the more interesting early experiments in concrete engineering and represented the proliferation of concrete for road and bridge construction. It is not known how many Marsh arches were built in Iowa in the 1910s and 1920s: judging from county records perhaps not more than one hundred. The large amount of reinforcing steel sheathed within a relatively thin skin of concrete has made them particularly vulnerable to rusting and spalling. As a result, only a few are known to remain. The Squaw Creek Bridge is distinguished as a well-preserved example of an indigenous structural type [adapted from Fraser 1992].


Arch bridge over Ioway (Formerly Squaw) Creek on 120th Street
Boone County, Iowa
Demolished and replaced with a slab of concrete.
Built 1917
- Marsh Engineering Co. of Des Moines, Iowa
Concrete March Rainbow arch (aka concrete bowstring through arch)
Span length: 76.1 ft.
Total length: 76.1 ft.
Deck width: 17.1 ft.
Posted to the National Register of Historic Places on June 25, 1998
Also called
Squaw Creek Bridge
Approximate latitude, longitude
+42.18089, -93.75803   (decimal degrees)
42°10'51" N, 93°45'29" W   (degrees°minutes'seconds")
Approximate UTM coordinates
15/437399/4670138 (zone/easting/northing)
Quadrangle map:
Land survey
T. 85 N., R. 25 W., Sec. 16
Inventory numbers
IA 78170 (Iowa bridge number)
NRHP 98000763 (National Register of Historic Places reference number)
BH 12905 (Bridgehunter.com ID)

Update Log 

  • January 26, 2011: Updated by Nathan Holth: This bridge has been demolished and replaced. Added Photos.
  • February 19, 2010: Updated by J.R. Manning: Updated bridge data


  • J.R. Manning - thekitchenguy [at] sbcglobal [dot] net
  • Nathan Holth


Mackey Bridge
Posted January 26, 2011, by David Backlin (us71 [at] cox [dot] net)

One of the first bridges I ever photographed was Lightning Creek in Kansas: http://bridgehunter.com/ks/crawford/lightning-creek/

Shortly after I took photos, it was replaced by a UCEB

Mackey Bridge
Posted January 26, 2011, by Matthew Lohry (matthewlohry [at] yahoo [dot] com)

Boy, the filthy toilet was certainly well-earned on this bonehead move, wasn't it?? I almost puked all over my monitor when I saw the replacement! This is one of the ugliest bridges I have ever seen in my life! This is a sore, sorry reminder of the replacement of the Shanley Road Bridge in Elk County, Pennsylvania--one of the most strikingly beautiful historic bridges ever built, foolishly replaced with such a nasty, ugly structure that it defies description! Ish!!

Mackey Bridge
Posted January 26, 2011, by Cliff Darby (clif30 [at] hotmail [dot] com)

The National Guard threw up (get it) a UCEB near my house after an overload blew out the timber stringer originally at the location. I give them a pass since its a defense project and the stringer wasn't historic. But man did they get that thing up fast... Matter of a couple weeks tops, and that includes new abutments.

Mackey Bridge
Posted January 26, 2011, by Jake (simpspin [at] yahoo [dot] com)

The toilet has more usefulness.

Mackey Bridge
Posted January 26, 2011, by Anthony Dillon (spansaver [at] hotmail [dot] com)

I've got their award right here!!!

Mackey Bridge
Posted January 26, 2011, by Nathan Holth (form3 [at] historicbridges [dot] org)

The replacement slab of concrete is so ugly it isn't worthy of being called a bridge. It won awards for accelerated bridge construction because it was built quickly. This is probably because it is so ugly the contractors could not wait to complete the project so they wouldn't have to look at the ugly thing every day.