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IAIS Big Bear Creek Bridge (Marengo)

Quadrangular Through Truss Bridge over Big Bear Creek
West of Marengo, Iowa County, Iowa

Click the Photo Above to See All Photos of This Bridge!
Name IAIS Big Bear Creek Bridge (Marengo)
Built By Chicago, Rock Island & Pacific Railroad
Contractor (Truss) Unknown
Contractor (Approach) American Bridge Company of New York
Currently Owned By Iowa Interstate Railroad
Length 310 Feet Total, 113 Foot Main Span
Width 1 Track
Height Above Ground 15 Feet (Estimated)
Superstructure Type Quadrangular Through Truss, Through Plate Girder and Precast Concrete Spans
Substructure Type Concrete
Date Built 1901, Approaches Built 1926 and Ca. 2010
Traffic Count 4 Trains/Day (Estimated)
Current Status In Use
IAIS Bridge Number 2686
Significance Moderate Significance
Documentation Date August 2013 and May 2017


Located to the west of Marengo, this bridge is the final crossing of Bear Creek, a series of streams running throughout Poweshiek and Iowa Counties.
Originally built in 1901, the bridge contained a pair of trusses. At some point, the western of these two trusses was replaced with a trio of deck girders.
In 1926, the deck girder spans would be replaced with a heavy duty through girder span. In addition, modular concrete girder spans were added to the east side in approximately 2010. These spans replaced standard trestle spans.
The main span of the bridge consists of a single 112'8" Quadrangular Through Truss with riveted connections. The portals form simple X shapes, and a date of 1901 is engraved into the portal.

The author has ranked this bridge as being moderately significant, due to the unique design of the trusses and the bleak future.
Iowa Interstate has begun a crusade to replace as many of the historic trusses on their routes as possible. Unfortunately, this truss bridge will likely be replaced in the near future.
The photo above is looking from US-6.

Citations

Source Type

Source

Build Date Portal Cutout
Railroad Line History Source ICC Valuation Information, Compiled by Richard S. Steele