Year constructed: 1892
Alternate name: South Skunk River Bridge
Bridge type: Pin/Rigid-Connected Warren Through Truss
National Register of Historic Places
status:
Listed
Length: 212 feet
Width: 16.1 feet
Spans: 1
FHWA: 195700
Jurisdiction: Jasper County
Location: County Road S74 over the South Skunk River, 4.5 miles northeast of Monroe, Section 23, T78N-R19W (Elk Creek Township)
Details
Called the Red Bridge locally, this medium-span truss carries a gravel-surfaced county road across the South Skunk River south of Reasoner in Fairview Township. Jasper County records indicate that the bridge was constructed at this location in 1892. Local bridge contractor H.S. Efnor held the county's annual bridge construction contract for that year, and he erected this bridge by September 1892 for $3,515.34. The bridge functioned as built until it was extensively damaged by flooding in 1947. The county then replaced one of the structure's original steel cylinder piers with concrete and added a pony truss approach span. The Red Bridge has functioned since in essentially unaltered condition.
The Pratt and Warren truss configurations were both developed in the 1840s, but it was the Pratt that received the most widespread use in the late 19th century. The reasons for this probably relate to the versatility of the pin-connected Pratt for different span lengths and its easier erection using timer falseworks. Although they later superseded the Pratt when the state highway commission developed its standard bridge designs in 1913, Warren trusses were rarely built in the 19th century; only a few pin-connected examples of this structural type were ever constructed Iowa. All but a handful of these have subsequently been razed. The Red Bridge is thus technologically significant as an intact example of this exceedingly rare structural type. Although substantially altered by the addition of the pony truss approach span, the bridge is an important and uncommon remnant of early Iowa transportation [adapted from Fraser 1990].