Bridging the County
As you drive along Wright County, you will come upon bridges on the major highways, country blacktops, and county gravel roads. In the USA, early bridges were usually made of wood, and may have been covered. After 1850 – about the time Wright County was being settled, the use of wrought iron increased, followed by steel and then concrete.
The bridges built before 1930 were usually “truss” bridges. And a truss bridge is not the same thing everywhere! A truss bridge has many design types, but most, if not all, tend to have the “V” shaped design. To further make a difference, the roadbed itself may be above the truss, in the middle of the truss (through truss), or on top of it (deck truss). A through truss will have the top connected across, where the half through or pony truss will be open at top.
Next time you are driving around, you may wish to take a picture of one of these bridges. The iron bridges are being replaced by concrete and will soon be just another part of history. The photo above is a "pony" truss located at Heartland Museum. Below is a bridge in Goldfield, and one over the Iowa River.