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Twin Bridge

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Photos 

Photo taken by Historic American Engineering Record

Map 

Description 

This long-span concrete arch spans the Volga River in Town Bridge Park, a small county park southwest of Fayette. The structure is made up of a single filled spandrel arch, with concrete substructure and guardrails. The Twin Bridge is one of several such arches built by the county under contract with Des Moines bridge contractor N.M. Stark. From about the turn of the century until 1913, Stark build virtually all of the county's concrete and steel bridges, holding a virtual monopoly on Fayette County bridge construction and even providing the designs for most of the structures. The design that Stark used for the concrete arches was the patented elliptical arch of Indianapolis engineer Daniel Luten. Stark was a licensee for Luten, building Luten arches under a patent royalty agreement. The Twin Bridge was build by Stark around 1910, under one of the multiple-bridge contracts executed between his firm and county. Since its completion, the structure has carried vehicular traffic, in unaltered condition. N.M. Stark was vigorous in his promotion of concrete for bridge construction in the early 20th century. Touting the Luten arch as an economical alternative to the steel truss, he was the state's most prolific concrete bridge builder during this time. This was due in large part to counties such as Fayette, Story and Marshall, which built numerous bridges under essentially non-competitive contracts with Stark in the years around 1910. But the Iowa State Highway Commission regarded Stark--with his patented bridges and monopolistic county contracts--as an exemplar of the worst of bridge contracting in the state. Beginning in 1913, the highway commission aggressively attacked Stark and the Luten patent, eventually getting the patent declared non-valid in court and getting Stark indicted for bid-rigging. As a result, Stark's business plummeted, and one of Iowa's most successful bridge builders soon faded into obscurity by the early 1920s. The Twin Bridge illustrates Stark's construction of the Luten arch. With its trademark profile and concrete guardrails with incised panels, it is a typically configured, example of this widespread and controversial structural type. And with its 80-foot span, the Twin Bridge is distinguished as the longest-span Luten arch remaining in Iowa [adapted from Fraser 1992].

Facts 

Overview
Concrete arch bridge over Little Volga River on 130th Street
Location
Fayette County, Iowa
Status
Open to traffic
History
Built ca. 1910 by N.M. Stark & Co.
Builder
- N.M. Stark & Co. of Des Moines, Iowa
Dimensions
Span length: 80.1 ft.
Total length: 80.1 ft.
Approximate latitude, longitude
+42.81799, -91.87735   (decimal degrees)
42°49'05" N, 91°52'38" W   (degrees°minutes'seconds")
Approximate UTM coordinates
15/591775/4741214 (zone/easting/northing)
Quadrangle map:
Maynard
Land survey
T. 92 N., R. 09 W., Sec. 02
Inventory numbers
IA 150440 (Iowa bridge number)
BH 13479 (Bridgehunter.com ID)
Inspection (as of 10/2011)
Appraisal: Structurally deficient
Sufficiency rating: 62.4 (out of 100)
Average daily traffic (as of 2009)
70

Update Log 

  • April 23, 2012: Updated by Luke Harden: Added category "HAER documented", added link to image on deviantArt
  • September 2, 2011: New photos from Jason Smith
  • June 18, 2008: Updated by Historic American Engineering Record
  • June 16, 2008: New photos from Historic American Engineering Record

Sources 

  • Historic American Engineering Record
  • HAER IA-53 - Twin Bridge
  • Jason Smith - JDSmith77 [at] gmx [dot] net
  • deviantArt - Image