Bridging the gap-A study on foldable tubular bridges

Abstract

Recent investigations on foldable structures and particularly foldable tubes, raise the question if they can be advantageous for the construction of bridge-like beams. Transporting a flat packed structure on site and deploying it there, instead of bringing or constructing the structure on site will have a positive impact on the grey energy. Although a straight beam shows a better performance than a folded one with identical cross-section, the energy saved in transportation might justify the effort. In order to be able to answer this complex question, many steps and investigations need to be done. This paper will answer some questions concerning foldable structures and their geometry-related structural performance. During the ongoing research on T-hedral tubes, the authors developed a strategy to generate flat-foldable tubular beams, on which this particular investigation is based. For the paper at hand a set of these beams, with different cross-sections and variable amount of folds will be compared with respect to their structural performance. The study will focus on their geometry without exact detailing of the hinges or the material thickness. With the help of a parametric model a generic solver [1] and a FEM-module [2] the authors developed a method that evaluates the beams based on their weight after optimisation, in final unfolded state as well as in different configurations during unfolding.