Dismountable steel tensegrity grids as alternate roof structures

摘要

This paper reviews the concept of tensegrity structures and proposes a new type of dismountable steel tensegrity grids for possible deployment as light-weight roof structures. It covers the fabrication of the prototype structures followed by their instrumentation, destructive testing and numerical analysis. First, a single module, measuring 1 m X 1 m in size, is fabricated based on half-cuboctahedron configuration using galvanised iron (GI) pipes as struts and high tensile stranded cables as tensile elements. Detailed instrumentation of the structure is carried out right at the fabrication stage. The structure is thereafter subjected to destructive test during which the strain and the displacement responses are carefully monitored. The structure is modelled and analyzed using finite element method (FEM) and the model generated is updated with the experimental results. The investigations are then extended to a 2 X 2 grid, measuring 2 m X 2 m in size, fabricated uniquely by the cohesive integration of four single tensegrity modules. After updating and validating on the 2 X 2 grid, the finite element model is extended to a 8 X 8 grid (consisting of 64 units and measuring 8 m X 8 m) whose behaviour is studied in detail for various load combinations expected to act on the structure. The results demonstrate that the proposed tensegrity grid structures are not only dismountable but also exhibit satisfactory behaviour from strength and serviceability point of view.