Wednesday, December 21, 2011
Corbelling Arches and Bridges in Irelend
In response to a comment John Scott made on a post I wrote last week concerning Arch Chronology, Patrick McAfee went on to add some other very interesting comments.
"I'd like to mention that we love to corbel here in Ireland and had done so for about 6,000 years when eventually we began to shape the underside of lintels to look like arches. We were happy enough with this until one day quite unexpectedly we were struck by the arrival of the real arch. Although this magically worked only in compression it was a bit too far for us because we were hung up on creating tension. It took many years for us to succumb to the show-off easy ways of compression. But every so often, quite unexpectedly, there is an outbreak of corbelling, I've done it myself, even on your continent. I cant help it, it's a neolithic gene thing.
.... I'd like to add a lesser known fact (probably only of interest to myself) to do with corbelling. It is to be found on some medieval (say 15th century) stone bridges here. They are arched, (pointed or slightly pointed is common) but from the springing stone up say a quarter to one third the rise of the arch the voussoirs are corbelled and not radiated towards centre points. Above that they are are radiated. I have not come across a good reason for it yet but it's common enough and must have had a purpose. "
Does anyone have any thoughts about this?