Non-Linear Structural Forms

With my background in architectural history I was intrigued by AEC Magazine’s article about non-linear structural forms which aim to span a maximum distance with minimal materials because it highlighted several unique architectural examples. If I understand the article correctly, non-linear structural forms are characterized by always being strictly in tension or compression. This includes the use of stretched membranes, flying buttresses, etc. This is in contrast to traditional structural forms like walls, columns and beams which can have a variety of forces acting upon them in combination but whose structural calculations result in linear equations.

Readers lucky enough to make it to the end of the article will have a new word for the day (at least I did): Tensegrity. It’s defined as the structural condition where elements are either in pure tension or compression with no two compression elements (theoretically) in contact. The article uses the wonderful example of Brisbane’s Kurilpa Bridge (pictured) to illustrate this point where it’s easy to see these forces in balance to create the span. Buckminster Fuller developed the theory while the above project was completed by Arup - and though I often give them a rough time on social media in jest - here again their engineering is totally on point. As an interesting side note, Arup used custom written software to integrate their calculations into Oasys’ GSA engineering software which from what I can gather specializes in non-linear statics resulting in a bridge that is truly a unique structure.