Long live the arch

Future-Proof: Navigate Threats, Seize Opportunities at ICNY 2018 | Jan 22-26 at the Marriott Marquis, Times Square, New York

If you've ever seen a picture of Stonehenge, the prehistoric monument near Salisbury, England, you'll recognize the structural system known as post and lintel. It consists of two upright blocks -- the posts -- with another block -- the lintel -- spanning the gap between them. This was the earliest type of structure used to span open space. The trouble was, the widest distance you could span with a post and lintel was limited to the size of the biggest stone lintel you could get your hands on -- not to mention lift into place. Hence, even the grandest ancient buildings under roof -- Egypt's vast temple at Karnak, for instance -- were little more than forests of stone columns with narrow passages left over in between. The invention that finally overcame this problem was the arch. It had humble enough beginnings. It was already known to the Babylonians, Assyrians, Greeks and others, often in the form of a roof over underground drains. Yet the Romans were the first to really ...