The effect of discrete reinforcement on the load?bearing behavior of a spindle?shaped Tensairity beam

Abstract

Tensairity is a lightweight structural concept, a synergistic combination of an air-beam, cables and struts, which is categorized as a pneumatic structure. The central idea of Tensairity is to use a low pressure of the internal air to stabilize compression elements against buckling. The basic element consists of a simple air-beam (a low pressure inflated tube), a compression element tightly connected to the air-beam and two tension cables having a spiral shape around the tube. Both the cables and the struts play the role of transferring the applied forces over the air inflated beam; the latter stabilizes then the compression element against buckling. This solution increases the load-carrying capacity compared to a traditional simple air-beam. At the same time, the pressure inside the air-tube can be lowered. Tensairity is, due to its characteristics, especially interesting for temporary and architectural applications, like roof structures, (temporary) bridges and tent structures. The applicability of the concept is not restricted to beams. It is also valid for columns or arches. The simplest Tensairity beam has a cylindrical geometry, but many other shapes are possible, too. Cigar-shaped or spindle-shaped beams still have a circular cross section, but are stiffer than the cylindrical structure.