I’ve been watching a narrowboat channel from England and there are very many beautiful brick bridges with a nice arch over the canal. I understand how the arch holds the bridge up.
I don’t understand how they built the arch in the first place without the bricks falling. They were built a couple hundred years ago.
In: 73
Generally speaking bridges were built starting from the bottom and going up. As such the first consideration was how many foundations it would have in the water across the span. Small spans might not even require any foundations in the water, while longer spans may require several arches. With longer arch spans supporting scaffolding below the deck is crucial until the bridge is complete whereas with multiple small arches you may get away with minimal supporting scaffolding as the two halves of the arch can mostly support themselves even before being connected because they don’t stretch over a long gap.
Building bridges is hard, and it was especially hard in the older times. The Romans were able to build surprisingly long and complex bridges with single or multiple arching spans, many of which survive today. However that did not mean that it was an easy feat. My personal favorite story is the one of the Arta bridge in Greece, which is a fairly long and tall multiple arch span stone bridge that was built around 400 years ago. The bridge has some folklore surrounding it, according to which supposedly the bridge kept collapsing and the master builder had to entomb his own wife in the foundations for the bridge to remain stable. Of course that’s just floklore, and we don’t actually know how the construction went, but there’s always a hint of truth in myths and folklore which is that probably collapsing during construction or shortly after it and needing multiple revisions to get it right was probably not uncommon. This was also an issue with domes for churches and temples.
Latest Answers