Design of an inflatable, modular and portable footbridge

Optimization of the use of resources and adaptability of the structures to their environment are new concerns in architecture and structural engineering. At the same time, ephemeral structures are gaining relevance in the market for their uses in maintenance and repair, organization of events, rescue and emergencies and temporary works.

Inflatable structures satisfy two of the points aforementioned: they require small amounts of materials and are adequate for ephemeral structures, due to their low deflated volume and lightness. They are also adaptable in the sense that their overpressure determines their load carrying capacity. However, they are inadequate for environments where high external loads may be present.

Tensairity appears as a solution to this problem, increasing the carrying capacity of inflatable structures without renouncing to their advantages. This technology adds two extra structural elements to inflatable beams, with greater strengths, in order to redistribute stresses along it. The inflatable element serves then to couple the two stiff elements and to avoid buckling.

This work presents and explores design possibilities of Tensairity beams with special focus on their computational modelling. Then, research is carried out regarding modular Tensairity beams, thought as a solution for deployable footbridges. A prototype was built and tested in serviceability conditions to prove the fitness of the proposal to a commercial level.