Geometric Constraints and Dynamic Behavior of a Deployable Footbridge

Abstract

This paper focuses on the design process of a deployable footbridge that meets the requirements of maximum compactness in its folded state, as well as minimum use of auxiliary means during the folding and unfolding process. The fundamental strategy to achieve this is to transform into cables all those elements whose tensile work is guaranteed, taking advantage of the possibility of posttensioning in order to make the whole system stiffer. The suitability of ensuring that these cables will not vary in length when folding the structure, avoiding the need for collection devices, gave rise to a series of geometric constraints that ended up conditioning the design of the prototype. On the other hand, the relationship between post-tensioning and the structure's period of vibration will be discussed, through the development of a dynamic analysis.