Cruciform Outriggers

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An outrigger is the strut, or compression member, that braces a truss web and keeps it vertical AND is position outboard of the truss web. Typically this is only a feature of a pony truss. If it were inboard of the web, it is often called an inrigger.

Cruciform means "cross shaped". In this case, if the strut is viewed from the end, it will have an cross, or "X" profile. The purpose of this shape is because a member under compression stress is subject to buckle, and the larger the cross-section dimension the longer it can be and still not buckle. By employing the cruciform shape, the cross section dimension is longer - but without weighing as much as it would if it were solid.

Most cruciform outriggers are forged with threaded rod ends and the entire middle has the cruciform shape. It is a feature typical only on early iron bridges, (before 1900) and is usually on struts not more than about 6 ft [2 m] long.


Austin Bridge (Neosho County, Kansas)
Built 1872 near Chanute by the King Iron Bridge Co. Moved downstream ca. 1910. Relocated to Santa Fe Park in Chanute, Kansas.
Relocated Bowstring through truss bridge over Little Turkey Creek
Open to pedestrians

Branch West Branch Mill Creek Bridge (Wabaunsee County, Kansas)
Queenpost pony truss bridge over Trib West Branch Mill Creek, 2.7 mi. west of Volland
Open to traffic

Camp Branch Bridge (Cass County, Missouri)
Pratt pony truss bridge over Camp Branch on private lane
Private, limited use

Cedar Creek-King Rd. Bridge (Jefferson County, Kansas)
Abandoned pony truss bridge over Cedar Creek on King Road (Abandoned)
Derelict/abandoned

Grasshopper Creek Bridge (Atchison County, Kansas)
Built ca. 1890.
Pratt pony truss bridge over Grasshopper Creek, 2.0 mi. north and 0.6 mi. west of Muscotah
Intact but closed to all traffic

Kent Park Bowstring Arch Bridge (Johnson County, Iowa)
Built in the 1870's over a tributary of Old Man's Creek in Liberty Township on Dane Road this bridge was moved to F.W. Kent Park in the late 1990's
Bowstring pony truss bridge on a trail at F.W. Kent County Park
Open to pedestrians

Little America Rest Area Bridge (Fulton County, Illinois)
Built ca.1875
Bowstring pony truss bridge over Park on Pedestrian Trail
Open to pedestrians

Little Walnut Creek Bowstring Bridge (Crawford County, Kansas)
Bowstring Pony Truss Bridge over Little Walnut Creek
Abandoned with portion of deck missing

Mulberry Creek Bridge (Fayette County, Texas)
Built 1888 by A.J. Tullock and Company; Replacement bridge built in 2001 and 1888 bridge relocated to a park in Schulenburg
Relocated Bedstead pony truss bridge. Formerly Hermis Road (CR 424) over Mulberry Creek
Relocated from Hermis Road (CR 424) to a park in Schulenburg and open to pedestrians.

Old Military Bridge (Bourbon County, Kansas)
Built ca. 1878. Closed to vehicular traffic in 1965. Wooden deck destroyed by fire in 1974.
Abandoned bowstring through truss bridge over Marmaton River on 240th Street
Abandoned

Springfield Bridge (Faulkner County, Arkansas)
The bridge was fabricated in 1871 but not installed over Cadron Creek until 1874. Removed November 2016 for relocation and restoration.
Bowstring through truss bridge over Beaverfork Lake on Beaverfork Park Trailway
Rehab by Workin, Bridges/Bach Steel completed on 8-10-17.