A bright blue iron bridge

Normally old iron truss bridges are painted in shades of green. Not this one, Shelby County Bridge #117 on CR 600 S. Bridgehunter.com has a 2010 photo showing a rusty green, but a 2016 shot shows a shiny bright blue paint job.

Approaching on CR 600S

The first bridge over Conn’s Creek at this location was a 16′ tall Pratt through truss built in 1892. Ironically it got a new concrete deck in 1912. The irony comes with the historic and horrific disastrous flood of 1913 which washed this bridge away. The original concrete abutments and wingwalls survived the flood and now support the replacement 7-panel, riveted Warren pony truss bridge. This bridge was built in 1925.

Looking at Conn’s Creek through truss

Truss outriggers and abutment and wing wall

Riveted hip connection

Diagonals, side rails and deck grate

You can see all 7 truss panels and deck grate

It is quite a visual as you approach this bright blue iron bridge. Like referenced above, you usually see green iron bridges, not blue. This is, however, a very nice bridge that spans a pretty little country creek.

For those of you interested in truss design details, HistoricBridges.org describes the design and structure: Concrete abutments and wingwalls support the single-span Warren pony truss. The riveted structure extends 87’6″ in seven panels. Its all-interior verticals are manufactured from pairs of angles riveted together with stay plates and reinforced with external sway bracing. Its diagonals are made from a pair of angles (doubled in the outer panel) also riveted together with stay plates. The I floor-beams are riveted to gussets and the verticals above the lower chord and carry the concrete deck. The weight and varied size of the diagonals, the placement of the floor-beams, and the integration of knee or external sway braces into the verticals indicate a late stage in the design of all-riveted Warren pony trusses.

 

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