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Historic Bridges in Minnesota
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Bridge L5665 in Blue Earth County.

Bridge L5665 on Township Road 167 over Le Sueur River

 

Bridge number: L5665

Year built: 1883

Contractor: Wrought Iron Bridge Company, Canton, Ohio

Overall length: 140.5 feet

Overall width: 16.8 feet

 

Adapted from National Register of Historic Places nomination written by Fredric L. Quivik, Renewable Technologies, Inc. The Kennedy Bridge was listed on the National Register of Historic Places in 1989.

 

 

Description

The Kennedy Bridge, located about 2-1/2 miles southeast of Mankato, carries unpaved Township Road 167 over the Le Sueur River about 3/4 mile east of Minnesota State Highway 22. The bridge is a 140-foot, single-span, wrought iron, pin-connected Pratt through truss bridge. The superstructure of the bridge is supported by stone abutments. The upper chords of the bridge consist of two iron channel sections riveted with a continuous iron top cover plate and batten plates along the lower flanges. The lower chords are punched iron eye-bars; the eye-bars at each end are two panels long. The hip vertical members are forged round iron rods, while the other verticals consist of two iron channel sections riveted with lacing bars. The diagonals are punched iron eye-bars. The counters are round iron turnbuckles. The wood plank deck is supported by timber stringers which sit atop variable-depth, built-up, iron girder floor beams. The floor beams at the hip verticals sit on plates supported by nuts threaded onto the lower ends of the hip verticals. The other floor beams are riveted to the vertical members above the pin-connections. Portal bracing consists of two latticed struts in combination with iron strap cross-bracing. Sway bracing consists of iron I-beam struts. The bridge retains excellent integrity.

 

 

Historic significance

The Kennedy Bridge is historically significant for its association with the late 19th century county-wide bridge building program in Blue Earth County. The bridge is also one of the few surviving wrought iron bridges in Minnesota.

 

As Minnesota's population grew early in the second half of the 19th century, a system of transportation evolved which featured railroad lines and a web a local roads leading from rural areas to shipping points along the railroads. These roads needed bridges over rivers and streams to insure year-round travel. Local township governments were responsible for building and maintaining these bridges. Recognizing the importance of reliable bridges to the welfare of its citizens, Blue Earth County embarked in the late 1860s on a program to build high-quality, permanent bridges. It is the first county in the state known to have taken over much of the responsibility for bridge building in the early 1870s. Blue Earth County was also one of the pioneering local governments in the state to shift from wood to wrought iron as the primary material for its bridge spans. Throughout the next three decades the county built numerous iron and then steel bridges at major crossings in its jurisdiction. After early experimentation with a variety of other structural configurations, the pin-connected Pratt truss became the most widely used type of wrought iron bridge.

 

On November 22, 1882, the Blue Earth County Commissioners awarded a contract to John Johnson to build abutments for a bridge at Kennedy's Ford. On January 4, 1883, the Commission awarded the Wrought Iron Bridge Company of Canton, Ohio, a contract to build the Kennedy Bridge and two other bridges for a total sum of $6,400. The Wrought Iron Bridge Company was one of the important early bridge fabricators and builders responsible for bringing the new structural material, wrought iron, to Minnesota for use in building bridges. By the end of the 19th century, Blue Earth County had built over 50 iron or steel truss bridges. Today, the Kennedy Bridge is one of only two surviving 19th century truss bridges in the county.