Rockwell City Bridge

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Map 

Street View 

Description 

This medium-span concrete Marsh arch stands just east of Rockwell City. The bridge traces its origins to 1915. That year the county requested that the state highway commission design a structure for this crossing of a small stream on the main highway into Rockwell City from the east. ISHC engineers delineated a concrete girder structure, comprised of two 34-foot spans supported by a concrete substructure. As an alternative, the county also commissioned Des Moines engineer James B. Marsh to design a single-span concrete arch, using his patented rainbow arch configuration. Featuring a 60-foot span, a 15-foot arch rise and an 18-foot roadway, the structure employed a fixed-span design, with the arch ribs extending below the floor line to bear into the concrete abutments. Additionally, Marsh's bridge structure featured his trademark slotted guardrails with paneled concrete bulkheads. On August 10th a contract to build this bridge and six others was awarded to the Iowa Bridge Company of Des Moines for an aggregate sum of $11,690. The arched version of the bridge was chosen by the supervisors. The bridge was completed in 1915 for a cost of $4,107.65. The county road was later incorporated as part of U.S. Highway 20, and the bridge carried relatively heavy traffic until it was replaced in a highway re-alignment in 1981. Today the bridge stands unused, in unaltered condition. This medium-span structure is significant as one of the last remaining examples in the state of James Marsh's patented bridge form. As he would for other bridges in the state, he offered his design for this bridge to Calhoun County as an alternative to the standard engineering of the state highway commission. Flush from the success of the Lake City Bridge, the county built Marsh's structure instead of the more prosaic girder design of the highway commission. The bridge is thus significant as a well-preserved, typically configured example of Marsh's patented arch type - one of only a few remaining examples in Iowa of this indigenous structural type [adapted from Fraser and Crow-Dolby 1992].

Categories 

Arch (12,650) Built 1915 (1,258) Built during 1910s (9,968) Calhoun County, Iowa (48) Have street view (28,882) Hawkeye Cutoff (3) Hawkeye Highway (23) Iowa (6,790) Iowa Bridge Co. (1902-193X) (55)

James Barney Marsh (10) Marsh arch (71) NR-listed (3,013) Open to pedestrians (4,580) Rainbow arch (257) Rockwell City, Iowa (3) Span length 50-75 feet (10,415) Total length 50-75 feet (9,564) US 20 (91)

Update Log 

• August 30, 2020: Updated by Luke: Land around bridge has been cleared/rehabbed for a roadside park featuring this bridge.
• November 17, 2015: New photos from Lee Smith
• January 5, 2015: New photo from Luke
• August 24, 2013: New Street View added by Dave King
• January 23, 2012: Updated by Luke Harden: Added stream name
• December 9, 2011: New photo from Luke Harden
• July 29, 2011: New photo from Luke Harden
• July 26, 2011: Updated by Luke Harden: Added NRHP info

Sources 

• Luke
• Historic Bridges of Iowa
• Dave King - DKinghawkfan [at] hotmail [dot] com
• Lee Smith - ljsmith_32 [at] hotmail [dot] com
• News Article

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