What Was the Problem With Iron Bridges?

shankar s./CC-BY 2.0

The problem with iron bridges was that the material was not as reliable as carbon steel, so it was replaced starting in the late 1800s and was completely unavailable for bridge building by the early 1900s. Bridges in the late 1700s were made of cast iron, but, by the early 1800s, cast iron gave way to wrought iron.