Nishnabotna River Bridge

T Ave. over Nishnabotna R., Manilla, Iowa

Map 

Description 

The availability of steel for domestic purposes like bridge building was severely limited during World War II. Most of the counties of Iowa, including Crawford County, turned to timber to fulfill their short-span bridge construction needs. In May of 1945, however, heavy flooding washed out 27 bridges and culverts throughout the county. It was decided to build replacement spans using steel. The Des Moines Steel Company was hired to design and fabricate the bridges. Forced to economize with material they turned to a bridge form that was popular in the 1860s and 1870s: the bowstring arch-truss. Although lacking the lateral stability of later bridge forms, the bowstring offered outstanding structural efficiency. During the period of the 1860s and 1870s thousands of bowstring arch-trusses were built throughout the nation. In a time of national crisis this once popular bridge form again supplied the solution. The Nishnabotna bridge is an excellent example of this series of bridges built during the war. -- Historic American Engineering Record (HAER IA-48)

National Register information 

Note: The following information comes from the NRHP database and has not been verified.
Status
Posted to the National Register of Historic Places on June 25, 1998
Reference number
98000801
Architectural style
Other architectural type; Bowstring pony arch truss
Area of significance
Engineering
Level of significance
State
Evaluation criteria
C - Design/Construction
Property type
Structure
Historic function
Road-related
Current function
Road-related
Period of significance
1925-1949
Significant year
ca. 1945

Sources