Structures

What holds an airplane together as it moves through the air or keeps a bridge from collapsing under the strain of cars? It’s all in the design of their structure.

A structure can be defined as a collection of materials intended to sustain loads. Our world is full of them: structures occur both in the biological and man-made world.

Biological structures, which are of course much older, transport matter and provide living things with protection. Present-day biological structures are mostly soft, like muscle tissue or flower petals. However, there are also rigid biological structural parts, like horns, bones, teeth or tree bark.

Artificial structures, on the other hand, are man-made. But in relative terms, humans haven’t been formally studying structures for very long at all.

The study of structures began in the seventeenth century, thanks largely to Galileo. Galileo had to switch disciplines after the Catholic Church threatened to persecute him for his work in the field of astronomy in 1633. He left astronomy behind and began studying the strength and character of different physical materials.

Galileo’s prestige brought greater academic attention to the subject. In the mid-1650s, scholars began researching the ways in which different materials and structures behave under heavy loads. That same century, Robert Hooke also discovered how matter behaves at an atomic level.

Hooke wrote that a structure can only resist a load by pushing back on it with an equal force. So, if a cathedral pushes down on a foundation with its weight, the foundation will either break or push back up with an equal force. This is one of the fundamental concepts of structures and their strength.