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North Skunk River Bridge

Mahaska County, Iowa
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Photos 

Photo taken by Julie Bowers

Map 

Description 

"After a personal investigation had been made of the site for the bridge over North Skunk River, between the counties of Poweshiek and Mahaska, the joint meeting was called at the rooms of the New Sharon Savings Bank at New Sharon, Iowa, to further discuss the matter," reported the Mahaska County Clerk in February 1919. The bridge that the two counties were contemplating would span the North Skunk River on the county line. The Iowa State Highway Commission bridge department had drawn up a 200-foot-span rigid-connected truss for the crossing late the previous year. Using the ISHC drawings, the two counties let the project out for competitive bids that spring. The contract was let to the Iowa Bridge Company of Des Moines for a 200'x18' pin connected high truss with concrete floor, steel tubular piers, and wood approach spans, complete as per plans, for a total cost of $50,000, $40,000 of which was to be paid jointly by Poweshiek and Mahaska counties and the balance of $10,000 to be paid by citizens of New Sharon and vicinity. Iowa Bridge used a superstructure fabricated by the American Bridge Company to build the bridge, completed later in 1919. The truss carried regional traffic in this location until it was replaced by another structure on U.S. 63. The 1920 truss was later dismantled and moved south one mile to its present location, where it was re-erected on concrete abutments. It now carries county-road traffic in unaltered condition. Why the North Skunk River Bridge was built using pinned connections instead of the riveted connections as drawn by the highway commission is not known, but it probably relates to cheaper costs for the former structural type. Today the bridge is distinguished as the longest example of its type. The subsequent move has diminished its historic significance somewhat, although in truth the new locations is only a mile form the original and both cross the North Skunk River. A well-preserved, long-span example of what - through more recent attrition - has become a relatively uncommon bridge type, the North Skunk River Bridge is an important highway-related resource [adapted from Fraser 1992].

View Uglybridges.com report

Facts 

Overview
Pinned Parker through truss bridge over North Skunk River on CR G13/110th Street
Location
Mahaska County, Iowa
Status
Open to traffic
History
Built 1920
Builders
- American Bridge Co. of New York
- Iowa Bridge Co. of Des Moines, Iowa
- Iowa State Highway Commission of Ames, Iowa
Design
Pinned Parker through truss
Dimensions
Length of largest span: 200.1 ft.
Total length: 202.1 ft.
Deck width: 17.1 ft.
Vertical clearance above deck: 10.0 ft.
Recognition
Posted to the National Register of Historic Places on May 15, 1998
Approximate latitude, longitude
+41.49432, -92.63433   (decimal degrees)
41°29'40" N, 92°38'04" W   (degrees°minutes'seconds")
Approximate UTM coordinates
15/530522/4593697 (zone/easting/northing)
Land survey
T. 77 N., R. 15 W., Sec. 7
USGS topographic map
New Sharon
Inventory numbers
IA 238030 (Iowa bridge number)
NRHP 98000503 (National Register of Historic Places reference number)
BH 13986 (Bridgehunter.com ID)
Inspection (as of 01/2012)
Deck condition rating: Fair (5 out of 9)
Superstructure condition rating: Satisfactory (6 out of 9)
Substructure condition rating: Satisfactory (6 out of 9)
Appraisal: Functionally obsolete
Sufficiency rating: 45.0 (out of 100)
Average daily traffic (as of 2010)
60

Categories 

A-frame portal (246)
American Bridge Co. (463)
Built 1920 (700)
Built during 1920s (7,046)
Functionally obsolete (7,054)
Iowa (3,615)
Iowa Bridge Co. (29)
Iowa State Highway Commission (15)
Mahaska County, Iowa (17)
NR-listed (2,355)
 Open (28,454)
Owned by county (16,526)
Parker through truss (954)
Parker truss (1,273)
Pin-connected (1,568)
Skunk River (68)
Span length 175-250 feet (1,489)
Through truss (9,254)
Total length 175-250 feet (2,806)
Truss (23,615)

Update Log 

  • August 9, 2012: Updated by Luke Harden: Added other builder
  • September 8, 2011: Updated by Luke Harden: Added builder
  • August 11, 2011: Updated by Luke Harden: Corrected build date, bridge type, added descrition and photographs

Sources 

  • Julie Bowers - jbowerz1 [at] gmail [dot] com
  • Luke Harden - lukemh9 [at] gmail [dot] com
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Comments 

North Skunk River Bridge
Posted April 25, 2011, by Nathan Holth (form3 [at] historicbridges [dot] org)

It would be a ca. 1920 bridge. It looks it might be one of Iowa's standard plan bridges for the period. I saw one similar, here: http://www.historicbridges.org/iowa/crt63/index.php

North Skunk River Bridge
Posted April 24, 2011, by K. A. Erickson

Julie,

Thanks for sharing.

More likely it was moved to present location in the 1960s, if the photographs posted are indeed of the bridge in question. On the portal frame there are the remains of a builders' plaque with the date 1920. I have noticed one similar and have a likely candidate in mind. It could very well have been constructed by the American Bridge Company as their plaques from that time period differ from earlier, later, least what I have seen.

Compare to this, image number 4 >

http://bridgehunter.com/wa/pierce/bh47982/

Many counties liked to reuse bridges. As traffic grew in one area build a new, modern one and shift the old someplace else.