Air Structure Terminology: Tensegrity

Air Structure Word of the Day: Tensegrity

Tensegrity sounds like an odd-Frankenstein of a word—and it is—but it holds special relevance in the world of air supported structures. While it’s not a word that you’ll find in the vocabulary of most people, it’s likely to be known by those that work in building design, like architects and engineers.

The word was coined by the inventor and architect, R. Buckminster Fuller, the clever inventor of another type of dome structure, the geodesic dome. Tensegrity was a logical combination of the two words tension and integrity and fit his needs for a word to describe his unique engineering ideas. The word describes the principle that the structural integrity, or how strong a structure is, is related to the amount of tension placed on that structure.

A typical construction gains its structural integrity through compression. In other words, bricks and beams with a lot of weight press down into a strong foundation to help keep the whole structure together.

This isn’t the only way for buildings or structures to keep their shape, though. With tensegrity, it’s not compression of the walls or joists that hold up the structure, but outside tension. So basically, a force that’s creating tension on the structure is actually what is holding the whole thing together.

But what does this mean in the world of air domes?

Well it’s exactly this principle that gives strength and support to an air supported structure. The tensegrity maintains the shape and helps it resist the forces of gravity and the winds that push against it. It’s just an obscure way to think about it that the air pressure itself is creating the tension. Instead of cables or ropes creating the tension, it’s the pressure differential between the inside and outside.

As soon as the tension is broken (i.e., the pressure is released), the dome will begin to sag.

Interestingly, as with most words, tensegrity has been appropriated for a single purpose and is typically used to describe a different type of construction. When talking about tensegrity structures, engineers are usually talking about cable and strut types of structures. In other words, the elements that hold things up, the struts, are themselves held in place through tension on cables that are attached to them.

Some of the most high-profile tensegrity structures are the Spodek structure in Poland and the Seoul Olympic Gymnastics Arena that was designed by David Geiger. There are also a good number of art pieces that were created with the principle of tensegrity—the structures often seem to defy logic.

Now that you’re an expert on tensegrity, if ever the chance comes up in conversation to use the word, you’ll be able to pull it out in complete confidence! Just don’t try using it in Scrabble. Unfortunately, tensegrity hasn’t made its way into the Official Scrabble dictionary—of course we checked!