Optimization of Footbridges Composed of Prismatic Tensegrity Modules

The architectural potential of tensegrity structures is proven. Yet, paradoxically, very few real construction projects have been built around the world. The main reasons are complex construction processes, lack of design and optimization guidelines, and excessive self-weight due to the prestress needed to guarantee stiffness and dynamic behavior. Hence, optimizing the stiffness and self-weight is a key aspect when designing a tensegrity footbridge. Previous research has demonstrated the validity of a design and optimization methodology, based on morphological indicators, that identifies geometry with a maximum stiffness and/or a minimum self-weight for a family of structures. In this paper, that methodology is applied to footbridges composed of tensegrity modules comprising simplex, quadruplex, pentaplex, and hexaplex types. A comparison of the stiffest and lightest structures is provided, a practical case study is developed, and the relevance and feasibility of such tensegrity footbridges are discussed. As a result, the study provides advice on optimum footbridge topologies with the following characteristics: excellent stiffness and dynamic behavior; efficient structures composed of simplex modules; and self-weight that is still rather high but similar to that of bended structures, although with potential to be reduced thanks to optimization of the prestress scenario.