This bridge is an example of an uncommon truss type, the
Camelback truss. The bridge is otherwise traditionally composed and aside
from the loss of original railings, appears unaltered and with good historic
integrity. Flooding has ripped added cable railings off parts of the bridge.
The bridge has been closed to all traffic. The bridge contains seven panels,
and is seated on stone abutments that have been supplemented with concrete.
Floorbeams are rolled i-beams, and the truss includes built-up beams which
are v-laced, and eyebars that are loop-forged.
Information and Findings From Iowa's Historic Bridge
Discussion of Bridge
in Eldorado, this medium-span truss carries an unpaved county road over
the Turkey River;. Known locally as the Eldorado Bridge, the structure
consists of a single pin-connected Camelback through truss, supported by
stone abutments. The Eldorado Bridge was constructed by contractor J.G.
Ratcliff of Waukon, Iowa, under contract with the Fayette County Board
of Supervisors. Completed in March 1899, it has functioned in place
since, in essentially unaltered condition.
through trusses were used extensively throughout Iowa for medium-span
crossings in the late 19th and early 20th centuries. For longer
crossings after the turn of the century, however, bridge companies could
develop greater efficiency with polygonal-chorded Pratt
variants--primarily Parker, Pennsylvania and Camelback trusses. With its
distinctive five-faceted upper chords, the Camelback configuration was
disdained by some engineers (including the venerable J.A.L. Waddell, who
called it "uncompromisingly ugly") for its tendency under certain
conditions to reverse compressive and tensile forces acting on their
individual members. As a result, Camelback trusses have never received
widespread acceptance. Relatively few were ever built on Iowa's roads,
and only a handful has been identified as extant by the bridge
inventory. The Eldorado Bridge is this technologically significant as a
well-preserved example of this uncommon structural type [adapted from
Original / Full Size Photos A collection of overview and detail photos. This gallery offers photos in the highest available resolution and file size in a touch-friendly popup viewer. Alternatively, Browse Without Using Viewer
Mobile Optimized Photos A collection of overview and detail photos. This gallery features data-friendly, fast-loading photos in a touch-friendly popup viewer. Alternatively, Browse Without Using Viewer